68Ga-prostate-specific membrane antigen positron emission tomography/computed tomography for patients with favorable intermediate-risk prostate cancer

IntroductionCurrent guidelines do not support the use of pretreatment imaging in patients with favorable intermediate-risk prostate cancer. ⁶⁸Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is more accurate than conventional imaging for preoperative staging. We aimed to evaluate whether pretreatment ⁶⁸Ga-PSMA PET/CT is beneficial for identifying pathological lymph node involvement (LNI) and adverse pathology among patients with favorable intermediate-risk prostate cancer.MethodsWe reviewed 88 patients with favorable intermediate-risk prostate cancer who underwent ⁶⁸Ga-PSMA PET/CT prior to radical prostatectomy and lymph node dissection from 2016–2020. The primary endpoint was the presence of pathological LNI. Association between pretreatment characteristics and outcomes were evaluated.ResultsPreoperative ⁶⁸Ga-PSMA PET/CT showed suspicious uptake in lymph nodes in 4/88 patients (5%), hence, 20 patients would need to be scanned to identify a patient with a positive lymph node on imaging. Two patients had pathological LNI, only one of whom showed ⁶⁸Ga-PSMA PET/CT uptake prior to surgery. The sensitivity, specificity, positive predictive value, and negative predictive values of ⁶⁸Ga-PSMA PET/CT for identifying LNI were 50%, 97%, 25%, and 99%, respectively. After surgery, four patients had evidence of prostate-specific antigen (PSA) persistence. The rate of PSA persistence was higher among patients with LNI on preoperative ⁶⁸Ga-PSMA PET/CT (2/4, 50% vs. 2/84, 2%, p=0.009).ConclusionsPreoperative imaging of favorable intermediate-risk prostate cancer patients using ⁶⁸Ga-PSMA PET/CT showed a low yield for identifying patients at higher risk. Consistent with current guidelines, our findings do not support the routine use of PET/CT in this group of patients. Future prospective studies are needed to validate our findings.     

Prostate cancer recurrence in patients with negative or equivocal conventional imaging: A role for 18F-fluciclovine-PET/CT in delineating sites of recurrence and identifying patients with oligometastatic disease

IntroductionDespite improvements in overall survival, biochemical recurrence of prostate cancer, characterized by rising prostate-specific antigen (PSA) levels after curative intent primary therapy, remains common. With the advent of highly sensitive molecular imaging, men with limited metastatic disease burden, or oligometastatic prostate cancer, are increasingly being identified. The LOCATE trial (NCT02680041) assessed the impact of positron emission tomography (PET) with ¹⁸F-fluciclovine on management of men with prostate cancer recurrence after curative intent primary therapy and negative/equivocal conventional imaging. Here, we use LOCATE data to characterize the sites of disease recurrence and explore the potential for ¹⁸F-fluciclovine-PET/CT to evaluate oligometastatic disease.MethodsEligible men (≥18 years; prior curative intent treatment of prostate cancer; recurrence based on rising PSA; negative/equivocal conventional imaging) underwent ¹⁸F-fluciclovine-PET/CT according to standard protocols. The primary outcome measure of the LOCATE trial was a revised management plan post-scan. We performed a secondary analysis of the LOCATE imaging data to characterize anatomical sites of disease recurrence and to explore the potential for ¹⁸F-fluciclovine-PET/CT to evaluate oligometastatic disease. Imaging results were stratified by baseline PSA levels and prior treatment(s) and the Fisher exact test used to analyze differences between groups. Oligometastatic disease was defined as 1–5 extraprostatic lesions (≤3 lesions in any single organ system) plus negative prostate/bed imaging (as a surrogate for primary tumor control).ResultsOf 213 enrolled patients, 164 (77%) had undergone prostatectomy as their initial treatment; their median PSA was 0.57ng/ml. For the 49 patients with an intact prostate, the median PSA was 5.5ng/ml. The overall ¹⁸F-fluciclovine-PET/CT detection rate was 57%. Detection rates were 84% in men with intact prostates and 49% in those who had undergone prostatectomy, with the difference being attributable to prostate/bed findings (71% vs. 18%, respectively). The detection rate in lymph nodes was 29% and in bone was 11%. In total, 53/213 (25%) had oligometastatic disease. Twenty (38%) oligometastatic patients had PSA ≤1.0 ng/ml. Forty-two (79%) experienced a change to their management plan following the scan, commonly to target a lesion identified by ¹⁸F-fluciclovine-PET/CT. The majority of management changes (74%) involved a new treatment modality; however, 10 patients (24%) experienced a modification of the existing plan for radiotherapy to incorporate a boost to an area guided by the ¹⁸F-fluciclovine-PET/CT results.ConclusionEven at low PSA levels, ¹⁸F-fluciclovine-PET/CT identified a diverse pattern of recurrence missed with conventional imaging. One-quarter of men had oligometastatic disease, raising the potential for ¹⁸F-fluciclovine-PET/CT to guide targeted treatment of oligometastases.     

Effect of hormonal therapy on 18F-fluciclovine PET/CT in the detection of prostate cancer recurrence,localization of metastatic disease,and correlation with prostate-specific antigen

Introduction¹⁸F-Fluciclovine, is a positron emission tomography (PET) radiotracer approved for the localization of sites of prostate cancer recurrence in men with a rising prostate-specific antigen (PSA) after definitive treatment. To explore the impact of androgen deprivation therapy (ADT) on the performance of ¹⁸F-fluciclovine, we conducted a retrospective analysis to compare the ¹⁸F-fluciclovine PET/CT positivity rate in patients receiving ADT at the time of the scan with the rate achieved in patients not receiving ADT.MethodsA retrospective review of data from patients who underwent ¹⁸F-fluciclovine PET/CT for biochemical recurrence of prostate cancer between December 2016 to March 2020 was performed. The cohort was divided into an ADT group (patient reportedly on ADT) and a non-ADT group (not currently receiving ADT). Patients with unknown ADT status or undetectable/unknown PSA were excluded. For each group, the number of positive ¹⁸F-fluciclovine PET/CT scans (positivity rate) was evaluated for the whole body, prostate/bed, and extraprostatic regions and rates were correlated with PSA. The Fisher's Exact test was applied to establish the significance between the ADT and non-ADT positivity groups. Mantel-Haenszel trend test was performed to assess linearity between the positivity rate and PSA level.ResultsIn 320 patients, the status of ADT was known. At the time of the ¹⁸F-fluciclovine scan, 68/320 (21%) patients were on ADT, while 252/320 (79%) were not. The median Gleason score was 8 (range of 6–10) in the ADT group vs. 7 (range of 6–10) in the non-ADT group (P < 0.001). Overall, positivity rates demonstrated no statistical significance between the ADT and non-ADT groups; Positivity rates (ADT vs. non-ADT) were 82% (56/68) vs. 82% (206/252) for the whole body, 57% (39/68) vs. 60% (152/252) for prostate/bed, and 60% (41/68) vs. 53% (133/252) for extraprostatic regions (P > 0.05). A positive linear correlation was noted between PSA and each group's positivity rate (P < 0.01). However, no significant difference was observed between ADT and non-ADT groups at different PSA levels (P > 0.05).ConclusionsDetection of prostate cancer recurrence with ¹⁸F-fluciclovine PET/CT is not significantly influenced by ADT, suggesting that localization of disease in patients with detectable PSA who are receiving ADT is feasible with ¹⁸F-fluciclovine.     

Gallium-68 Prostate-specific Membrane Antigen Positron Emission Tomography in Advanced Prostate Cancer—Updated Diagnostic Utility,Sensitivity, Specificity,and Distribution of Prostate-specific Membrane Antigen-avid Lesions: A Systematic Review and Meta-analysis

ContextAccurate staging of high-risk localised, advanced, and metastatic prostate cancer is becoming increasingly more important in guiding local and systemic treatment. Gallium-68 prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has increasingly been utilised globally to assess the local and metastatic burden of prostate cancer, typically in biochemically recurrent or advanced disease. Following our previous meta-analysis, a high-volume series has been reported highlighting the utility of ⁶⁸Ga-PSMA PET in this setting.ObjectiveTo perform a systematic review and meta-analysis to update reported predictors of positive ⁶⁸Ga-PSMA PET according to prior therapy and proportion of positivity in various anatomical locations with sensitivity and specificity profiles.Evidence acquisitionWe performed critical reviews of MEDLINE, EMBASE, ScienceDirect, Cochrane Libraries, and Web of Science databases in July 2018 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Quality assessment was performed using Quality Assessment if Diagnostic Accuracy Studies-2 tool. Meta-analyses of proportions were performed using a random-effect model. Summary sensitivity and specificity values were obtained by fitting bivariate hierarchical regression models.Evidence synthesisA total of 37 articles including 4790 patients were analysed. For patients with biochemical recurrence, positive ⁶⁸Ga-PSMA PET scans increased with higher pre-PET prostate-specific antigen (PSA) levels. For PSA categories 0–0.19, 0.2–0.49, 0.5–0.99, 1–1.99, and ≥2 ng/ml, the percentages of positive scans were 33%, 45%, 59%, 75%, and 95%, respectively. No significant differences in positivity were noted between Gleason sums ≤7 and ≥8. Significant differences in positivity after biochemical recurrence in the prostate bed were noted between radical prostatectomy (22%) and radiotherapy (52%) patients. On per-node analysis, high sensitivity (75%) and specificity (99%) were observed.ConclusionsGa-68-PSMA PET improves detection of metastases with biochemical recurrence, particularly at low pre-PET PSA levels of >0.2 ng/ml (33%) and 0.2–0.5 ng/ml (45%). Ga-68-PSMA-PET produces favourable sensitivity and specificity profiles on meta-analysis of pooled data. This analysis highlights different anatomic patterns of metastatic spread according to PSMA PET in the primary and biochemically recurrent settings.Patient summaryGallium-68 prostate-specific membrane antigen positron emission tomography is now an established imaging technique that has been developed in response to inadequacies in standard of care imaging modalities to improve the detection of metastatic disease in prostate cancer, particularly in the setting of disease recurrence. To date, this imaging modality in the setting of primary staging is controversial, given the paucity of data. In light of the growing body of evidence, we summarised the data to date to provide clinicians with an overview of this imaging modality.     

18F-fluciclovine PET CT detection of biochemical recurrent prostate cancer at specific PSA thresholds after definitive treatment

ObjectivesTo evaluate various Prostate-Specific Antigen (PSA) thresholds at which a ¹⁸F-fluciclovine PET scan could be considered in the setting of biochemical recurrent prostate cancer after definitive treatment.MethodsWe analyzed available records of men who underwent a ¹⁸F-fluciclovine PET scan after definitive therapy at a single academic institution between November 2016 to May 2018. The primary outcome was the rate of positive imaging findings at specific PSA thresholds. We then employed empiric strategies including a ROC curve and decision curve analysis to identify a specific threshold for which obtaining a positive result would be optimized.ResultsA total of 115 men underwent imaging with ¹⁸F-fluciclovine PET. No concerning lesions were identified in 25 (21.7%) patients, 32 (27.8%) had a solitary lesion identified, 45 (39.1%) had 2 to 5 lesions, and 13 (11.3%) had greater than 5 suspicious lesions identified. At PSA thresholds of less than 0.5, 0.5 to 2.0, and greater than 2, lesions were detected in 55.5% (12/22), 70.6% (24/34), and 91.5% (54/59) of patients respectively [P < 0.001]. Our ROC analysis yielded a PSA threshold of 2.10 while our decision curve analysis provided a PSA cutoff of 1.38.ConclusionThis study constitutes an early single institution series evaluating the use of ¹⁸F-fluciclovine PET scans in the assessment of biochemically recurrent prostate cancer after definitive treatment. The probability of having positive imaging findings and increasing numbers of suspicious lesions rises with increasing PSA. Utilization of a lower PSA threshold of 0.5 may allow earlier intervention with salvage therapies in biochemical recurrence. However, using a threshold below 1 carries a higher risk of negative scans. Employing a higher PSA threshold of 1 to 2 carries greater sensitivity and specificity and may maximize identifying individuals with early BCR who may benefit from early intervention, while minimizing negative scans.     

Salvage lymph node dissection for prostate-specific membrane antigen (PSMA) positron emission tomography (PET)-identified oligometastatic disease

IntroductionThe availability of prostate-specific membrane antigen (PSMA) positron emission tomography (PET)/computed tomography (CT) imaging, particularly in the setting of rising prostate-specific antigen (PSA) after definitive treatment, has led to oligometastatic prostate cancer being increasingly identified. Despite the enthusiasm surrounding treating oligometastatic disease, it has been relatively understudied. We sought to review our salvage lymphadenectomy experience in the PSMA PET/CT era.MethodsWe retrospectively reviewed patients undergoing lymphadenectomy following curative-intent primary therapy with rising PSA who had undergone a PSMA PET/CT identifying oligometastatic disease (defined as ≤5 PSMA-avid lesions) between January 2016 and April 2020. The primary endpoint was complete response, defined as achieving a PSA <0.2 ng/ml without concomitant androgen deprivation therapy (ADT).ResultsTwenty-two patients were included. Primary curative therapy included radical prostatectomy (86.4%) and brachytherapy (13.6%). Median PSA at salvage surgery was 1.72 ng/ml. Pelvic lymph node dissection was the most performed procedure (72.7%). Median node yield was 10.5, with a median of 1.5 positive nodes on pathology. Eight patients (36.4%) achieved PSA <0.2, with six (27.3%) remaining with PSA <0.2 after a median followup of 23.1 months. Nine (40.9%) had an initial PSA decline, but nadired ≥0.2, and in five (22.7%) the PSA rose immediately after surgery. Overall, ADT was started in seven patients (31.8%) at a median of 10.1 months post-salvage surgery.ConclusionsIn our series of salvage dissection for PSMA-PET-detected nodal oligometastases, approximately a third achieved PSA <0.2; yet, it was only durable in 27%. Prospective trials of salvage nodal radiation are ongoing, however, more prospective trials of salvage node dissection are needed.     

68Ga-PSMA-11 PET/TC en la recidiva bioquímica oculta del carcinoma de próstata,con 18F-Colina PET/TC negativa. Valoración preliminar de su uso clínico

ObjectiveTo assess the clinical usefulness of ⁶⁸Ga-PSMA PET/CT studies in patients with occult biochemical recurrence of prostate carcinoma, with negative or inconclusive radiologic and 18F-Choline PET/CT imaging studies.Material and methodsRetrospective observational and diagnostic accuracy. The first 14 patients with a history of prostate carcinoma, treated with curative intent and presenting suspicion of biochemical recurrence with low PSA values (< 3 ng/ml) were selected. Imaging studies, prostate ultrasound, pelvic CT and/or MRI were negative, and all of them had a negative or inconclusive 18F-Choline PET/CT.All patients were referred to ⁶⁸Ga-PSMA-11 PET/CT. Protocol: Dose 2.2 MBq/kg. 20 mg furosemide at start. PET/CT images from skull base to proximal third of thighs at 60 min, and late images at 3 hours if needed.ResultsThe ⁶⁸Ga-PSMA-11 PET/CT was able to localize the occult biochemical recurrence in 9 of the 14 patients (64.2%), and it affected the therapeutic attitude in all of them.Four patients (28.5%) obtained a negative or inconclusive ⁶⁸Ga-PSMA-11 PET/CT and continued under vigilant approach with PSA controls and imaging studies according to the clinical guidelines. These patients had the lowest PSA values (less than 1 ng/ml).One of the ⁶⁸Ga-PSMA-11 PET/CT studies was inconclusive, reporting the presence of a doubtful right iliac adenopathy.Conclusión⁶⁸Ga-PSMA-11 PET/CT allows an early diagnosis, with low PSA values, of occult biochemical recurrence of prostate carcinoma, even in patients with negative 18F-Choline PET/CT.     

Imaging of prostate cancer with PET/CT and radioactively labeled choline derivates

PET- and PET/CT using [¹¹C]- and [¹⁸F]-labeled choline derivates are increasingly being used for imaging of prostate cancer. The value of PET- and PET/CT with [¹¹C]- and [¹⁸F]-labeled choline derivates in biochemical recurrence of prostate cancer has been examined in many studies and demonstrates an increasing importance. PET/CT, in comparison to PET, improves especially the lesion localization as well as characterization. Primary prostate cancer can be detected with moderate sensitivity using PET and PET/CT using [¹¹C]- and [¹⁸F]-labeled choline derivates—the differentiation between benign prostatic hyperplasia, prostatitis, or high-grade intraepithelial neoplasia (HGPIN) is not always possible. At the present time, [¹¹C]-choline PET/CT is not recommended in the primary setting but may be utilized in clinically suspected prostate cancer with repeatedly negative prostate biopsies, in preparation of a focused re-biopsy. Promising results have been obtained for the use of PET and PET/CT with [¹¹C]- and [¹⁸F]-labeled choline derivates in patients with biochemical recurrence. The detection rate of choline PET and PET/CT for local, regional, and distant recurrence in patients with a biochemical recurrence shows a linear correlation with PSA value at the time of imaging and reaches about 75% in patients with PSA > 3 ng/ml. Even at PSA values below 1 ng/ml, the recurrence can be diagnosed with choline PET/CT in approximately one-third of the patients. PET and PET/CT with [¹¹C]- and [¹⁸F]-choline derivates can be helpful in the clinical setting for choosing a therapeutic strategy in the sense of an individualized treatment: an early diagnosis of recurrence is crucial to the choice of optimal treatment. Especially important for the choice of treatment is the exact localization of the site of recurrence: local recurrence, recurrence as lymph node metastasis, or systemic recurrence, as it has direct influence on individual therapy. This article reviews the use of PET and PET/CT with [¹¹C]- and [¹⁸F]-labeled choline derivates in prostate cancer imaging with special emphasis on patients with biochemical recurrence. We briefly provide an overview of PET tracers for prostate cancer imaging, the rationale of using choline derivatives for prostate cancer imaging and discuss the contribution of choline PET/CT in patients suffering from prostate cancer with an emphasis on recurrent disease. Furthermore, we provide an outlook on future prospects of choline PET/CT imaging for therapy guidance and monitoring in the framework of therapy individualization.     

Utilidad de la tomografía de emisión de positrones / tomografía computarizada con 18F-colina en el manejo terapéutico de pacientes con recidiva bioquímica de adenocarcinoma de próstata tratados con braquiterapia

ObjectiveThe objective of the study was to evaluate the usefulness of 18F-choline PET/CT in biochemically recurrent prostate cancer patients treated with brachytherapy, as well as to assess the changes in therapeutic management derived from its outcome.Material and methodsRetrospective study of 20 patients between 51 and 78 years old, with a history of prostate adenocarcinoma that had been treated with brachytherapy and presented biochemical recurrence (PSA 3.1-12  ng/ml) and staging tests (CT and bone scan) without alterations, were included. The findings visualized in the PET/CT scan with ¹⁸F-choline were correlated with the histopathology and/or the evolution of the PSA after therapy.Results¹⁸F-choline PET/CT scan only detected local recurrence in 15 patients. Local and regional recurrences were seen in 4 patients, and 1 patient presented local and bone recurrence. Local recurrence detected in PET was confirmed by anatomopathological studies in 85% of the cases. In one patient, these findings (PET scan) turned out to be prostatitis, and it could not be confirmed in another patient. Of the cases with local and regional recurrence, local recurrence was histologically confirmed in 3 out of 4 patients. ¹⁸F-choline PET/CT changed the therapeutic management in 25% of the patients, discarding the initially planned salvage surgery in 3 cases, 1 radiotherapy and 1 brachytherapy.Conclusion¹⁸F-choline PET/CT could be a useful technique in the group of patients with biochemical recurrence after brachytherapy, providing locoregional and distant involvement findings which had not been detected with conventional imaging tests, thus determining a more adequate therapeutic management.     

Is Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Imaging Cost-effective in Prostate Cancer: An Analysis Informed by the proPSMA Trial

BackgroundBefore integrating prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) into routine care, it is important to assess if the benefits justify the differences in resource use.ObjectiveTo determine the cost-effectiveness of PSMA-PET/CT when compared with conventional imaging.Design, setting, and participantsA cost-effectiveness analysis was developed using data from the proPSMA study. proPSMA included patients with high-risk prostate cancer assigned to conventional imaging or ⁶⁸Ga-PSMA-11 PET/CT with planned health economics data collected. The cost-effectiveness analysis was conducted from an Australian societal perspective.Intervention⁶⁸Ga-PSMA-11 PET/CT compared with conventional imaging (CT and bone scan).Outcome measurements and statistical analysisThe primary outcome from proPSMA was diagnostic accuracy (nodal and distant metastases). This informed a decision tree analysis of the cost per accurate diagnosis.Results and limitationsThe estimated cost per scan for PSMA PET/CT was AUD$1203, which was less than the conventional imaging cost at AUD$1412. PSMA PET/CT was thus dominant, having both better accuracy and a lower cost. This resulted in a cost of AUD$959 saved per additional accurate detection of nodal disease, and AUD$1412 saved for additional accurate detection of distant metastases. The results were most sensitive to variations in the number of men scanned for each ⁶⁸Ga-PSMA-11 production run. Subsequent research is required to assess the long-term costs and benefits of PSMA PET/CT-directed care.ConclusionsPSMA PET/CT has lower direct comparative costs and greater accuracy compared to conventional imaging for initial staging of men with high-risk prostate cancer. This provides a compelling case for adopting PSMA PET/CT into clinical practice.Patient summaryThe proPSMA study demonstrated that prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) better detects disease that has spread beyond the prostate compared with conventional imaging. Our analysis shows that PSMA PET/CT is also less costly than conventional imaging for the detection of disease spread.This research was presented at the European Association of Nuclear Medicine Scientific Meeting in October 2020.     

Fluorinated deoxyglucose positron emission tomography imaging in progressive metastatic prostate cancer

Objectives. To correlate the abnormalities on computed tomography, magnetic resonance imaging, and bone scan with fluorinated deoxyglucose positron emission tomography (FDG-PET) in patients with progressive metastatic prostate cancer, using a lesion-by-lesion analysis, and to preliminarily explore post-treatment changes in standard uptake value (SUV) with changes in prostate-specific antigen (PSA).Methods. A lesional analysis compared abnormalities on FDG-PET with those on CT/MRI or bone scan. Patients had rising PSA levels and progressive disease according to the imaging findings. Changes in the SUV were compared with the PSA changes in patients who had serial scans after treatment.Results. One hundred fifty-seven lesions in 17 patients were examined; 134 osseous lesions were evident on PET and/or bone scan, 95 lesions (71%) were evident on both, 31 (23%) were seen only on bone scan, and 8 (6%) were seen only on PET (adjusted McNemar’s chi-square = 8.32, P = 0.004). All but one of the lesions seen only on bone scan were “stable” compared with the previous bone scans. All lesions seen only on PET proved to be active disease on subsequent bone scans. Twenty-three soft-tissue lesions were present on CT/MRI or PET, or both; 9 (39%) lesions were evident on both and 14 (61%) were evident only on one imaging modality. In 9 (75%) of 12 cases in which serial PET scans were available, the SUV changed in parallel with the PSA level.Conclusions. FDG-PET can discriminate active osseous disease from scintigraphically quiescent lesions in patients with progressive metastatic prostate cancer, but it is limited in detecting soft-tissue metastases. Post-treatment changes in the SUV tend to correlate with changes in PSA.     

“Real-world” evaluation of 18F-Choline PET/CT practices in prostate cancer patients and impact on changes in therapeutic strategy

ObjectivesThe role of ¹⁸F-fluorocholine positron emission tomography/computed tomography (¹⁸F-Choline PET/CT) in different clinical situations remains controversial and current practices are very heterogeneous. The aim of this study was to evaluate the “real-world” practice of ¹⁸F-Choline PET/CT in patients with prostate cancer and its potential impacts on therapeutic strategy.Methods and materialsThis is a retrospective multicenter observational study including 265 consecutive men who underwent ¹⁸F-Choline PET/CT for prostate cancer between November 2014 and November 2015. Primary outcome was impact on therapeutic strategy. Secondary outcomes were sensitivity of the ¹⁸F-Choline PET/CT and predictive factors associated with positive scans. Statistical analyses comprised Student's t test for continuous variables or chi-squared test for qualitative variables.ResultsMedian PSA level at the time of PET/CT was 4.19 ng/ml. The decision to perform PET/CT was made after multidisciplinary discussion in 29.8% of cases; most were prescribed by urologists (50.2% of cases). Three main indications were concerned: biochemical recurrence after local treatment (61.1%), initial staging (26.0%), or at the time of progression to castration-resistance (12.9%). Upon biochemical recurrence, ¹⁸F-Choline PET/CT allowed identification of ≥1 site(s) with a sensitivity of 80.9%. In multivariate analysis, predictive factors associated with ¹⁸F-Choline PET/CT sensitivity were serum PSA level and local treatment type in cases of biochemical recurrence, and PSA doubling time and Gleason score in case of initial staging. ¹⁸F-Choline PET/CT results allowed restaging and change in therapeutic strategy in 58.1% of all combined indications.ConclusionsIndications of ¹⁸F-Choline PET/CT were varied. The detection rate of metastatic lesions was suitable, especially when PSA rate was >1 ng/mL. In most cases, ¹⁸F-Choline PET/CT led to a change in therapeutic strategy, particularly in the setting of biochemical recurrence.     

Clinical value of 18FDG PET/MRI in muscle-invasive,locally advanced,and metastatic bladder cancer

ObjectiveMetastatic bladder cancer is an aggressive disease that can often be difficult to diagnose and stage with conventional cross-sectional imaging. The primary objective of this study was to determine the clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/MRI for surveillance and restaging of patients with muscle-invasive, locally advanced, and metastatic bladder cancer compared to conventional imaging methods.Materials and MethodsThis retrospective study enrolled patients with muscle-invasive, locally advanced and metastatic bladder cancer in a single institute evaluated with ¹⁸F-FDG PET/MRI. All patients also underwent conventional imaging with CT. Additional imaging may also have included ¹⁸F-FDG PET/CT (¹⁸F-FDG PET), or sodium fluoride (NaF) PET/CT in some patients. Images were reviewed by a diagnostic radiologist/nuclear medicine physician. Number of lesions and sites of disease were captured and compared between ¹⁸F-FDG PET/MRI and conventional imaging. Lesions were confirmed by sequential imaging or lesion biopsy. All patients were followed for survival.ResultsFifteen patients (4 for surveillance; 11 for restaging) underwent 34 ¹⁸F-FDG PET/MRI scans. Each patient received a corresponding conventional CT around the time of the ¹⁸F-FDG PET/MRI (median 6 days). The 15 patients (11 male; 4 female) had a median age of 61.5 years (range 37–73) and histologies of urothelial carcinoma (n = 13) and small-cell carcinoma of the bladder (n = 2) diagnosed as stage 4 (n = 13), stage 3 (n = 1), or stage 2 (n = 1). ¹⁸F-FDG PET/MRI detected 82 metastatic malignant lesions involving lymph nodes (n = 22), liver (n = 10), lung (n = 34), soft tissue (n = 12), adrenal glands (n = 1), prostate (n = 1), and bone (n = 2) with a resultant advantage of 36% for lesion visibility in comparison with CT. Serial imaging or biopsy confirmed these lesions as malignant.Conclusion¹⁸F-FDG PET/MRI can detect metastatic lesions which cannot be identified on conventional CT, and this can allow for better treatment planning and improved disease monitoring during therapy.     

The influence of 18F-fluorodeoxyglucose positron emission tomography/computed tomography on the N- and M-staging and subsequent clinical management of intrahepatic cholangiocarcinoma

BackgroundIntrahepatic cholangiocarcinoma (ICC) is a highly metastatic cancer. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) enables sensitive tumor and metastasis detection. Our aim is to evaluate the influence of pre-treatment PET/CT on the N- and M-staging and subsequent clinical management in ICC patients.MethodsBetween August 2010 and August 2018, 660 consecutive ICC patients, without prior anti-tumor treatments nor other malignancies, were enrolled. The diagnostic performance of PET/CT on the N- and M-staging was compared with conventional imaging, and the preoperative staging accuracy and treatment re-allocation by PET/CT were retrospectively calculated. Survival difference was compared between patients receiving PET/CT or not after propensity score matching.ResultsPatients were divided into group A (n=291) and group B (n=369) according to whether PET/CT was performed. Among 291 patients with both PET/CT and conventional imaging for staging in group A, PET/CT showed significantly higher sensitivity (83.0% vs. 70.5%, P=0.001), specificity (88.3% vs. 74.9%, P<0.001) and accuracy (86.3% vs. 73.2%, P<0.001) than conventional imaging in diagnosing regional lymph node metastasis, as well as higher sensitivity (87.8% vs. 67.6%, P<0.001) and accuracy (93.5% vs. 89.3%, P=0.023) in diagnosing distant metastasis. Overall, PET/CT improved the accuracy of preoperative staging from 60.1% to 71.8% (P<0.001), and modified clinical treatment strategy in 5.8% (17/291) of ICC patients, with unique roles in different tumor-node-metastasis (TNM) stages. High tumor-to-non-tumor ratio (TNR) predicted poor overall survival [hazard ratio (HR) = 2.17; 95% confidence interval (CI): 1.49–3.15; P<0.001]. Furthermore, patients performing PET/CT had longer overall survival compared with those without PET/CT (HR =0.74; 95% CI: 0.58–0.93; P=0.011) after propensity score matching.ConclusionsPET/CT was valuable for diagnosing regional lymph node metastasis and distant metastasis in ICC patients, and facilitated accurate tumor staging and optimal treatment allocation.     

PET und PET/CT in der Rezidivdiagnostik des Prostatakarzinoms

Of patients with carcinoma of the prostate undergoing therapeutic regimes with curative intent, 15–23% will ultimately relapse and 16–35% will need some sort of salvage therapy within 5 years. Of relapsing patients, 50% will have local recurrence and 50% systemic disease with or without local recurrence. Therefore, localization of recurrent prostate cancer is critical for selecting a local or systemic therapeutic strategy. Modern fusion imaging with PET/CT and ¹¹C/¹⁸F-choline or ¹¹C-acetate has augmented the diagnostic imaging spectrum for assessment of relapsing prostate cancer. In 60–70% of patients with biochemical relapse, recurrent tumor can be detected and anatomically precisely localized. Detection sensitivity is probably negatively correlated with serum PSA concentration. Below a PSA level of 1 ng/ml, mean detection sensitivity is probably 50–66%. Fusion imaging with ¹¹C-choline PET/CT and MRI possesses a high potential for early localization of recurrent prostate carcinoma.     

Combined 18F‐fluorocholine and 18F‐fluoride positron emission tomography/computed tomography imaging for staging of high‐risk prostate cancer

Study Type – Diagnosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Positron emission tomography/computed tomography (PET/CT) with choline and fluoride for the detection of metastases in patients with prostate cancer have each been evaluated, with mixed results. Choline PET/CT has been evaluated against pelvic lymphadenectomy, generally with a low sensitivity but a high specificity; however, the study populations have been heterogenous. Fluoride PET/CT has been evaluated against other imaging methods, such as bone scan, single photon emission CT and MRI, and has been shown to have high specificity as well as sensitivity for bone metastases, but there are no studies with biopsy verification. This is the first study that evaluates the clinical use of both choline and fluoride PET/CT on the same patients in a well‐defined population of patients with high‐risk prostate cancer.

OBJECTIVE

• ? To investigate how often positron emission tomography/computed tomography (PET/CT) scans, with both ¹⁸F‐fluorocholine and ¹⁸F‐fluoride as markers, add clinically relevant information for patients with prostate cancer who have high‐risk tumours and a normal or inconclusive planar bone scan.

PATIENTS AND METHODS

• ? Patients with prostate cancer with prostate specific antigen (PSA) levels between 20 and 99 ng/mL and/or Gleason score 8–10 tumours, planned for treatment with curative intent based on routine staging with a negative or inconclusive bone scan, were further investigated with a ¹⁸F‐fluorocholine and a ¹⁸F‐fluoride PET/CT.
• ? None of the patients received hormonal therapy before the staging procedures were completed.

RESULTS

• ? For 50 of the 90 included patients (56%) one or both PET/CT scans indicated metastases.
• ? ¹⁸F‐fluorocholine PET/CT indicated lymph node metastases and/or bone metastases in 35 patients (39%).
• ? ¹⁸F‐fluoride PET/CT was suggestive for bone metastases in 37 patients (41%).
• ? In 18 patients (20%) the PET/CT scans indicated widespread metastases, leading to a change in therapy intent from curative to non‐curative.
• ? Of the patients with positive scans, 74% had Gleason score 8–10 tumours. Of the patients with Gleason score 8–10 tumours, 64% had positive scans.

CONCLUSIONS

• ? PET/CT scans with ¹⁸F‐fluorocholine and ¹⁸F‐fluoride commonly detect metastases in patients with high‐risk prostate cancer and a negative or inconclusive bone scan.
• ? For 20% of the patients the results of the PET/CT scans changed the treatment plan.

     

Safety and feasibility of image-guided robotic radiosurgery for patients with limited bone metastases of prostate cancer

ObjectiveTo determine the safety and feasibility after image-guided single fraction robotic stereotactic radiosurgery (SRS) in patients with bone metastases of prostate cancer.Materials and methodsForty patients with 64 bone metastases of prostate cancer were prospectively enrolled in a single center study and underwent 54 consecutive outpatient single session SRS procedures during a 4-year period. F-18 choline PET/CT in addition to standard CT imaging was done prior to SRS in all patients. Nineteen patients were under anti-androgen therapy, 8 patients had undergone chemotherapy before SRS. Overall survival and freedom from local tumor recurrence was analyzed with the Kaplan-Meier method.ResultsMean follow-up was 14 months (3–48 months). Seventy-five percent of patients had a single bone metastasis. The median tumor volume was 13 cc. The mean prescribed tumor dose was 20.2 Gy (16.5–22 Gy). Eight patients had died at the time point of the data analysis. The actuarial 6-months, 12-months, and 24-months local tumor control rate was 95.5% (95% CI: 83.0–98.8) as measured by MRI and PET CT imaging. The median initial PSA before SRS was 5.4 ng/dl (CI: 1.4–8.2) and dropped to 2.7 ng/dl (CI: 0.14–10) after 3 months. One case of progressive neurological deficits was documented.ConclusionsThis first report on single session, image-guided robotic SRS documents a safe, feasible, and patient-friendly treatment option in selected patients with bone metastases of prostate cancer.     

MRI/PET Imaging in elevated PSA and localized prostate cancer: a narrative review

ObjectiveTo review the recent milestones in MRI and PET based imaging and evaluate their evolving role in the setting of elevated PSA as well as localized prostate cancer.BackgroundThe importance of multiparametric MRI (mpMRI) and PET based imaging for the diagnosis and staging of prostate cancer cannot be understated. Accurate staging has become another significant milestone with the use of PET scans, particularly with prostate specific radiotracers like 68-Gallium Prostate Specific Membrane Antigen (68Ga-PSMA). Integrated PET/MRI systems are commercially available and can be modulated to evaluate the unique needs of localized as well as recurrent prostate cancer.MethodsA literature search was performed using PubMed and Google Scholar using the MeSH compliant and other keywords that included prostate cancer, PSA, mpMRI, PET CT, PET/MRI.ConclusionsmpMRI has now established itself as the gold-standard of local prostate imaging and has been incorporated into international guidelines as part of the diagnostic work-up of prostate cancer. PSMA PET/CT has shown superiority over conventional imaging even in staging of localized prostate cancer based on recent randomized control data. Imaging parameters from PET/MRI have been shown to be associated with malignancy, Gleason score and tumour volume. As mpMRI and PSMA PET/CT become more ubiquitous and established; we can anticipate more high-quality data, cost optimization and increasing availability of PET/MRI to be ready for primetime in localized prostate cancer.     

Performance characteristics of 18F-fluciclovine positron emission tomography/computed tomography prior to retroperitoneal lymph node dissection

IntroductionWe aimed to determine whether anti-1-amino-3-¹⁸F-fluorocyclobutane-1-carboxylic acid (¹⁸F-fluciclovine) positron emission tomography/computed tomography (PET/CT) can accurately detect residual non-seminomatous germ cell tumor (NSGCT) prior to retroperitoneal lymph node dissection (RPLND). There is no reliable way to differentiate between fibrosis/necrosis, teratoma, and viable germ cell tumor in patients receiving post-chemotherapy RPLND. Functional imaging, including ¹⁸F-fludeoxyglucose (18F-FDG) PET/CT, has been disappointing. Due to the need for better imaging modalities, our prospective, pilot study aims to investigate the accuracy of ¹⁸F-fluciclovine PET/CT in detecting residual tumor prior to RPLND.MethodsFrom March 2018 to May 2019, 10 eligible patients underwent preoperative ¹⁸F-fluciclovine PET/CT prior to undergoing bilateral, full-template RPLND or excision of mass (for one re-do RPLND) in a prospective, phase 2 study. Correlation between ¹⁸F-fluciclovine PET/CT and RPLND pathology were evaluated on a per-patient level.ResultsA total of 10 patients (mean age 29±7.6 years) underwent ¹⁸F-fluciclovine PET/CT prior to surgery. Nine of 10 patients received chemotherapy prior to RPLND. Correlation between ¹⁸F-fluciclovine PET/CT and RPLND pathology was seen in 3/10 (30%) patients. Five of 10 patients (50%) with negative ¹⁸F-fluciclovine PET/CT were found to have residual disease/teratoma on RPLND. Compared to the reference standard of RPLND, ¹⁸F-fluciclovine PET/CT demonstrated 29% sensitivity and 33% specificity. No patients experienced any adverse events due to ¹⁸F-fluciclovine PET/CT.ConclusionsDespite a different mechanism of action from ¹⁸F-FDG, ¹⁸F-fluciclovine has low sensitivity and specificity for residual teratoma in the retroperitoneum.