Novel imaging modalities for lymph node imaging in urologic oncology

Accurate lymph node staging in genitourinary (GU) malignancies is important for planning an appropriate treatment and establishing an accurate prognosis. This article discusses the novel imaging techniques for detection of metastases in various GU malignancies, including prostate, bladder, penile, and testicular cancers. Discussion includes nuclear medicine techniques of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT), (11)C-choline and (18)F-choline PET/CT, and ProstaScint scanning, as well as sentinel lymph node mapping. Magnetic resonance (MR) techniques include lymphotropic nanoparticle-enhanced MR imaging and diffusion-weighted MR imaging.     

Diagnostic performance of 18F-DCFPyL positron emission tomography/computed tomography for biochemically recurrent prostate cancer and change-of-management analysis

IntroductionConventional imaging (CI) performs poorly to identify sites of disease in biochemically recurrent prostate cancer. ⁶⁸Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) is most studied but has a very short half-life. This study reports the diagnostic performance of the novel prostate-specific membrane antigen (PSMA) radiotracer ¹⁸F-DCFPyL using real-life data and tumor board simulation to estimate the impact of ¹⁸F-DCFPyL PET on patient management.MethodsNinety-three ¹⁸F-DCFPyL PET/CT scans performed for patients previously treated for prostate cancer with a rising prostate-specific antigen (PSA) were retrospectively compared to contemporary CI and clinical imaging and PSA followups. A chart review was performed to document prior imaging, pathology results, serial serum PSA measurements, and other pertinent clinical data. Clinical utility of ¹⁸F-DCFPyL PET was measured using a simulated tumor board formed by three physicians with extensive prostate cancer experience deciding on management with and without knowledge of PET/CT results.ResultsAt median PSA 2.27 (interquartile rage [IQR] 5.27], 82% of ¹⁸F-DCFPyL PET/CT demonstrated at least one site of disease: non-regional lymph nodes (37% of scans), regional lymph node metastases (28%), local recurrence (27%), and bone metastases (20%), with higher PET positivity at higher PSA. Compared to ¹⁸F-DCFPyL PET/CT, CI showed overall poor performance, with accuracy below 20% for all extent of disease. PET/CT changed management in 44% of cases. The most frequent scenario was a radical change from initiating androgen deprivation therapy (ADT) to stereotactic body radiotherapy (SBRT) of oligo-lesional disease. In univariate and multivariate analysis, no patient characteristic could predict change of management by PET/CT results.Conclusions¹⁸F-DCFPyL significantly outperforms CI in recurring prostate cancer and is likely to impact management.     

Comparative efficacy of positron emission tomography with FDG and computed tomographic scanning in preoperative staging of non-small cell lung cancer

OBJECTIVE: To determine the sensitivity, specificity, and accuracy of positron emission tomography with 2-fluorine-18-fluorodeoxyglucose (PET-FDG) in the preoperative staging (N and M staging) of patients with lung cancer. The authors wanted to compare the efficacy of PET scanning with currently used computed tomography (CT) scanning. MATERIALS AND METHODS: Results of whole-body PET-FDG imaging and CT scans were compared with histologic findings for the presence or absence of lymph node disease or metastatic sites. Sampling of mediastinal lymph nodes was performed using mediastinoscopy or thoracotomy. RESULTS: PET-FDG imaging was significantly more sensitive, specific, and accurate for detecting N disease than CT. PET changed N staging in 35% and M staging in 11% of patients. CT scans helped in accurate anatomic localization of 6/57 PET lymph node abnormalities. CONCLUSION: PET-FDG is a reliable method for preoperative staging of patients with lung cancer and would help to optimize management of these patients. Accurate lymph node staging of lung cancer may be ideally performed by simultaneous review of PET and CT scans.     

Dual-Time <Superscript>18</Superscript>F-FDG PET/CT Imaging in Initial Locoregional Staging of Breast Carcinoma: Comparison with Conventional Imaging and Pathological Prognostic Factors

The aims of this retrospective study were to consider the diagnostic role of dual-time ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) in detection of breast carcinoma and axillary lymph node (ALN) status and to evaluate the primary tumor ¹⁸F-FDG uptake pattern. Preoperative staging was performed by ¹⁸F-FDG PET/CT in 78 female patients with breast carcinoma. Conventional imaging results were evaluated by breast magnetic resonance imaging (MRI) of 79 lesions in 78 patients, bilateral mammography (MMG) of 40 lesions in 40 patients, and breast ultrasonography (USG) of 47 lesions in 46 patients. The primary tumor detection rate using ¹⁸F-FDG PET/CT was higher than those using MRI, USG, and MMG. The sensitivity and specificity of ¹⁸F-FDG PET/CT scans for detecting multifocality were higher than those of MRI. The specificity of ALN metastasis detection with MRI was higher than that with ¹⁸F-FDG PET/CT, but ¹⁸F-FDG PET/CT had higher sensitivity. Higher ¹⁸F-FDG uptake levels were detected in patients with ALN metastasis, histologic grade 3, estrogen–progesterone-negative receptor status, lymphatic invasion, and moderate to poor prognostic groups. There was no statistical difference for the retention index in categorical pathological parameters except for progesterone-negative status. In conclusion, ¹⁸F-FDG PET/CT scans may be a valuable imaging technique for evaluating primary tumor and axillary status in staging breast carcinoma and ¹⁸F-FDG uptake may be a prognostic factor that indicates aggressive tumor biology and poor prognosis. Dual-time imaging in breast carcinoma staging may not be used for predicting pathological criteria and the aggressiveness of primary lesions.     

Diagnosis and monitoring of urological tumors using positron emission tomography.

The purpose of this article was to critically review the diagnostic value of positron emission tomography (PET) in urological oncology. Urinary tract tumor assessment is hampered by the renal elimination of (18)F-fluorodeoxyglucose (FDG), the most commonly used PET radiopharmaceutical. PET imaging offers no significant benefits over conventional imaging modalities for renal cell and bladder carcinomas. As a result of the low metabolic activity of prostate cancer, PET does not differentiate adequately between adenoma and carcinoma, nor detect local recurrence after radical prostatectomy with sufficient sensitivity. However, lymph node staging with FDG-PET, specifically in bladder cancer, has been shown to have a potential clinical benefit. Further studies are required to determine the clinical value of retroperitoneal lymph node staging and recurrent disease detection in germ cell tumors. Finally, encouraging early results exist for the use of serial PET measurements to predict and assess therapy response to chemotherapy which may also be valuable in urological oncology.     

18F-fluorocholine PET/CT compared with extended pelvic lymph node dissection in high-risk prostate cancer

Purpose

To compare ¹⁸F-fluorocholine positron-emission tomography/computed tomography (PET/CT) with extended pelvic lymph node dissection (ePLND) for the detection of lymph node metastases in a large cohort of patients with high-risk prostate cancer.

Materials and methods

Patients with prostate-specific antigen levels between 20 and 99 ng/mL and/or Gleason score 8–10 cancers, planned for treatment with curative intent following a negative or inconclusive standard bone scan, were investigated with ¹⁸F-fluorocholine PET/CT followed by an ePLND. None of the patients received hormonal therapy prior to these staging procedures. Results for PET/CT were compared on a per-patient basis with histopathology from ePLND. Sensitivity, specificity, positive and negative predictive values were calculated.

Results

PET/CT detected a total of 76 suspected lymph node metastases and four suspected bone metastases in 33 (29 %) of the 112 included patients. Of these, 35 suspected lymph node metastases, only within the anatomical template area of an ePLND, were found in 21 of the patients. Histopathology of the ePLND specimens detected 117 lymph node metastases in 48 (43 %) of the 112 patients. Per-patient sensitivity, specificity, positive and negative predictive values for ¹⁸F-fluorocholine PET/CT for lymph node metastases within the ePLND template were 0.33, 0.92, 0.76 and 0.65, respectively. Only 11 patients had lymph nodes larger than 10 mm that would have been reported by CT alone.

Conclusions

¹⁸F-fluorocholine PET/CT detects lymph node metastases in a significant proportion of patients with high-risk prostate cancer with a high specificity, but low sensitivity.     

FDG-PET/CT for the Preoperative Lymph Node Staging of Invasive Bladder Cancer

Background

Locoregional lymph node metastasis is an important prognostic factor in patients with bladder cancer. Multimodal treatment, depending on preoperative stage, may improve survival. The standard imaging modalities for staging (computed tomography [CT] or magnetic resonance imaging [MRI]) have an accuracy range of 70–90% for lymph node staging. A more accurate preoperative diagnostic test could improve survival rates even more.

Objective

To determine whether the use of 2-deoxy-2 [F] fluoro-D-glucose (FDG) positron emission tomography (PET) in combination with CT (FDG-PET/CT) can increase the reliability of preoperative lymph node staging in patients with nonmetastatic invasive bladder cancer (T2 or higher, M0) or recurrent high-risk superficial disease (T1G3 with or without Tis, M0).

Design, setting, and participants

Fifty-one patients underwent a preoperative FDG-PET/CT between April 2004 and December 2007. Independent of the result for lymph node status, all patients underwent a radical cystectomy and an extended lymphadenectomy. The FDG-PET/CT and CT results were compared with the definitive pathologic results.

Measurements

Among the 51 patients, 13 patients had metastatically involved locoregional lymph nodes, diagnosed on histopathology. In six patients, these nodes demonstrated increased FDG uptake on PET. In seven patients, PET/CT did not diagnose the positive lymph nodes. PET/CT was false positive in one patient.

Results and limitations

For the diagnosis of node-positive disease, the accuracy, the sensitivity, and the specificity of FDG-PET/CT were 84%, 46%, and 97%, respectively. When analysing the results of CT alone, there was accuracy of 80%, sensitivity of 46%, and specificity of 92%. The use of FDG-PET/CT is hampered by technical limitations.

Conclusions

We found no advantage for combined FDG-PET/CT over CT alone for lymph node staging of invasive bladder cancer or recurrent high-risk superficial disease.     

Application of whole-body positron emission tomography in the imaging of esophageal cancer: Report of a case

We describe herein a case of esophageal cancer in which both primary and metastatic lymph node foci were successfully imaged with whole-body positron emission tomography (PET) scanning. A 75-year-old woman with biopsy-proven squamous cell carcinoma of the esophagus underwent whole-body PET scanning for staging evaluation. The patient was injected with 373.7 MBq [¹⁸F]-2-fluoro-2-d-deoxyglucose (FDG), and 60 min later, scanning was performed from the neck to the pelvis. The whole-body images showed intense FDG uptake in the primary lesion and multiple focal areas of increased FDG uptake in the mediastinum and abdomen, which corresponded to the lymph node foci confirmed by computed tomography (CT) scan. To our knowledge, this is the first report of whole-body PET scanning being applied in the imaging of esophageal cancer.     

Imaging Prostate Cancer: An Update on Positron Emission Tomography and Magnetic Resonance Imaging

Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an essential role in the clinical management of patients. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Developments in imaging technologies, specifically magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT), have improved the detection rate of prostate cancer. MRI has improved lesion detection and local staging. Furthermore, MRI allows functional assessment with techniques such as diffusion-weighted MRI, MR spectroscopy, and dynamic contrast-enhanced MRI. The most common PET radiotracer, ¹⁸F-fluorodeoxyglucose, is not very useful in prostate cancer. However, in recent years other PET tracers have improved the accuracy of PET/CT imaging of prostate cancer. Among these, choline (labeled with ¹⁸F or ¹¹C), ¹¹C-acetate, and ¹⁸F-fluoride have demonstrated promising results, and other new radiopharmaceuticals are currently under evaluation in preclinical and clinical studies.     

Prospective Analysis of Accuracy of Positron Emission Tomography,Computed Tomography,and Endoscopic Ultrasonography in Staging of Adenocarcinoma of the Esophagus and the Esophagogastric Junction

Background: Exact preoperative staging of esophageal cancer is essential for accurate prognosis and selection of appropriate treatment modalities.Methods: Forty-two patients with adenocarcinoma of the esophagus or the esophagogastric junction suitable for radical esophageal resection were staged with positron emission tomography (PET), spiral computed tomography (CT), and endoscopic ultrasonography (EUS).Results: Diagnostic sensitivity for the primary tumor was 83% for PET and 67% for CT; for local peritumoral lymph node metastasis, it was 37% for PET and 89% for EUS; and for distant metastasis, it was 47% for PET and 33% for CT. Diagnostic specificity for local lymph node metastasis was 100% with PET and 54% with EUS, and for distant metastasis, it was 89% for PET and 96% for CT. Accuracy for locoregional lymph node metastasis was 63% for PET, 66% for CT, and 75% for EUS, and for distant metastasis, it was 74% with PET and 74% with CT. Of the 10 patients who were considered inoperable during surgery, PET identified 7 and CT 4. The false-negative diagnoses of stage IV disease in PET were peritoneal carcinomatosis in two patients, abdominal para-aortic cancer growth in one, metastatic lymph nodes by the celiac artery in four, and metastases in the pancreas in one. PET showed false-positive lymph nodes at the jugulum in three patients.Conclusions: The diagnostic value of PET in the staging of adenocarcinoma of the esophagus and the esophagogastric junction is limited because of low accuracy in staging of paratumoral and distant lymph nodes. PET does, however, seem to detect organ metastases better than CT.     

Positron-emission tomography with 18F-2-fluoro-2-deoxy-D-glucose (18FDG-PET) in the diagnosis of retroperitoneal lymph-node metastases from testicular tumors

Summary In 1991, this prospectively designed study was started to assess the potentials of positron emission tomography with ¹⁸FDG in the diagnostic workup for the detection of lymph node metastases in testicular cancer, since there were no data available concerning this subject at this time. In 54 patients (27 patients with pure seminoma, 27 patients with non-seminomatous tumors) ¹⁸FDG-PET results were compared with the findings obtained with abdominal computed tomography, serum level of tumor markers (AFP, β -HCG), and the histopathological findings after primary or post-chemotherapy retroperitoneal lymph node dissection. In 21 patients with pure seminoma (clinical stage I according to the Lugano classification) ¹⁸FDG-PET results were identical with those of the abdominal computed tomography, so PET does not add relevant informations in this group of patients. In 7 patients presenting with non-seminomatous testicular cancer (stage I), PET was not able to detect the existing micrometastases in 4 patients. In 1/7 case PET examination showed a suspicious focal lesion, this lymph node had 2 micrometastases within inflammatory changes. In 1/7 patient ¹⁸FDG-PET definitely revealed metastatic lesions, while the CT scans where judged to be unobtrusive and tumor marker levels were within the normal range. In the 4 patients with pure seminomas stage II B and II C (N = 6), that have undergone retroperitoneal lymph node dissection following chemotherapy, ¹⁸FDG-PET correctly predicted absence of tumor in 3 out of these 4, and in 1/4 patient the benign nature of a persistent large tumor after two cycles of polychemotherapy was correctly identified wich eventually turned out to be a ganglioneuroma. This lesion falsely was classified as malignant tumor with abdominal computed tomography, and in 2/4 patients post-chemotherapy residual retroperitoneal lesions in the CT scans could not be assessed exactly whether or not malignant tumor was present. In 20 patients presenting with non-seminomatous testicular cancer (stage II and III) ¹⁸FDG-PET was able to demonstrate therapeutic effects of chemotherapy by showing decreasing tracer activity in those regions, that had hypermetabolic foci prior to chemotherapy. It became evident in testicular cancer that there is a single entity which is not characterized by increased glucose metabolism, the mature teratoma. In lesions detected by abdominal computed tomography which do not present increased ¹⁸FDG uptake, mature teratoma as well as scar/necrosis or rare other tumors with normal glucose metabolism can be supposed, but additional characteristics based on different ¹⁸FDG uptake were not observed. In 1/20 case post-chemotherapy PET scan detected a hypermetabolic lesion, which was suspicious for metastatic spread, but in the histopathological examination this lesion was identified as inflammatory tissue reaction. Based on the data reported here in ¹⁸FDG-PET cannot be considered a standard diagnostic tool in the staging examinations in testicular cancer. It is of clinical relevance in patients who present residual tumor after chemotherapy. In this situation ¹⁸FDG-PET is helpful in deciding whether or not a residual mass post-chemotherapy contains active tumor. ¹⁸FDG-PET can not replace retroperitoneal lymph node dissection for staging purposes.      

Evaluation of fluorodeoxyglucose positron‐emission tomography with computed tomography for staging of urothelial carcinoma

Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVE

To investigate the role of ¹⁸F‐fluorodeoxyglusose positron‐emission tomography (FDG‐PET), combined with computed tomography (CT) and forced diuresis, in the staging and follow‐up of urothelial carcinoma (UC).

PATIENTS AND METHODS

We recruited 44 patients with muscle‐invasive urothelial bladder cancer (UBC) before radical cystectomy (RC), 19 under follow‐up after RC and seven after systemic chemotherapy. For those who had RC, histopathology was used as the reference standard to compare the sensitivity and specificity of FDG‐PET/CT and standard CT in detecting UBC and pelvic lymph node metastasis. Furthermore, 36 patients with ≥6 months of follow‐up imaging were considered to describe the progression of UC and extrapelvic positive FDG‐PET/CT images.

RESULTS

For the detection of primary UBC, FDG‐PET/CT was slightly more sensitive than CT (85% vs 77%) but less specific (25% vs 50%). For the detection of pelvic node metastasis FDG‐PET/CT was more sensitive than CT (57% vs 33%) with a specificity of 100% for both imaging techniques. In 20 patients, extrapelvic FDG‐PET/CT images showed suspected disease at the first evaluation. UC progressed in nine of the 10 patients who had synchronous multiple PET‐positive retroperitoneal or mediastinal lymph nodes, and in only two of the nine with unique hyperactive lesions in the lung. FDG‐PET/CT also detected a pT1G3 UC of the renal pelvis and all bone metastases detected by bone scintigraphy.

CONCLUSIONS

FDG‐PET/CT could replace standard CT and bone scintigraphy in the presurgical staging and monitoring of patients with UC after surgery or chemotherapy.     

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.     

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.     

[18F]‐fluorocholine positron‐emission/computed tomography for lymph node staging of patients with prostate cancer: preliminary results of a prospective study

Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVES

To evaluate prospectively [¹⁸F]‐fluorocholine positron‐emission/computed tomography (FCH PET/CT) for lymph node staging of prostate cancer before intended curative therapy, and to determine whether imaging 15 or 60 min after radiotracer injection is preferable.

PATIENTS AND METHODS

In all, 25 consecutive patients with newly diagnosed prostate cancer (Gleason score >6, and/or a prostate‐specific antigen level of >10 ng/mL, and/or T3 cancer) were scanned before lymphadenectomy. Each patient was assessed twice with imaging, at 15 and 60 min after the injection with FCH. Images were compared with the results of histopathological examination of the surgically removed lymph nodes. Maximum standardized uptake values (SUV_max) at 15 and 60 min were also compared.

RESULTS

Histopathologically, metastases were present in removed lymph nodes from three patients. FCH PET/CT showed a high radiotracer uptake in four patients, the former three and a fourth. The sensitivity, specificity, positive and negative predictive value of FCH PET/CT for patient based lymph node staging of prostate cancer were 100%, 95%, 75% and 100%, respectively; the corresponding 95% confidence intervals were 29.2–100%, 77.2–99.9%, 19.4–99.4% and 83.9–100%, respectively. Values of SUV_max at early and late imaging were not significantly different.

CONCLUSIONS

This small series supports the use of FCH PET/CT as a tool for lymph node staging of patients with prostate cancer. Values of SUV_max at early and late imaging did not differ. However, larger prospective studies are needed to validate these findings.     

Preoperative lymph-node staging of invasive urothelial bladder cancer with 18F-fluorodeoxyglucose positron emission tomography/computed axial tomography and magnetic resonance imaging: correlation with histopathology

OBJECTIVE: The treatment and prognosis of bladder cancer are based on the depth of primary tumour invasion and the presence of metastases. A highly accurate preoperative tumour, node, metastasis (TNM) staging is critical to proper patient management and treatment. This study retrospectively investigated the value of 1?F-fluorodeoxyglucose (FDG) positron emission tomography/computed axial tomography (1?F-FDG PET/CT) and magnetic resonance imaging (MRI) for preoperative N staging of bladder cancer. Material and methods. From June 2006 to January 2008, 48 consecutive patients diagnosed with bladder cancer were referred to preoperative staging including MRI and 1?F-FDG PET/CT. Eighteen out of 48 patients underwent radical cystoprostatectomy including removal of lymph nodes for histology, and were included in the study. Values of 1?F-FDG PET/CT and MRI for regional N staging were compared to histopathology findings, the gold standard. Results. 1?F-FDG PET/CT and MRI were performed in 18 patients. The specificities for detection of lymph-node metastases for MRI and 1?F-FDG PET/CT were 80% (n = 15) and 93.33% (n = 15), respectively. The negative predictive values were 80% (n = 15) and 87.5% (n = 16) for MRI and 1?F-FDG PET/CT, respectively. The differences in specificity and negative predictive values were not statistically significant. Conclusions. No significant statistical difference between 1?F-FDG PET/CT and MRI for preoperative N staging of urothelial bladder cancer was found in the study. However, the trend of the data indicates an advantage of 1?F-FDG PET/CT over MRI. Larger prospective studies are needed to elucidate the role of 1?F-FDG PET/CT in N staging of bladder cancer.     

Utility of ¹⁸F-FDG PET/CT in identifying penile squamous cell carcinoma metastatic lymph nodes

ObjectivesDue to the significant potential morbidity of inguinal and pelvic lymphadenectomy, the search for an imaging modality that can accurately identify penile squamous cell carcinoma (SCCA) lymphatic metastases continues. Initial ¹⁸F-FDG PET/CT studies have reported 80% sensitivity and 100% specificity in the detection of inguinal and obturator lymph node metastasis. We review a single institutional experience of ¹⁸F-FDG PET/CT imaging of SCCA of the penis to assess for accuracy and potential impact on clinical management.MethodsThree patients diagnosed with penile SCCA at a single institution underwent staging ¹⁸F-FDG PET/CT and went on to subsequent inguinal lymph node dissection. The ¹⁸F-FDG PET machine was a Philips Gemini Time-of-Flight PET with LYSO crystals with 4.7 mm spatial resolution. The CT was a 16-slice helical CT with 5 mm slice widths. ¹⁸F-FDG PET/CT findings were compared with the histologic findings of these procedures. Decision to proceed with lymphadenectomy was based on clinical judgment of a single urologist and all fused ¹⁸F-FDG PET/CT imaging was assessed by a single experienced radiologist.ResultsNo patient received chemotherapy or radiation before the ¹⁸F-FDG PET/CT or surgery. The first patient was obese (BMI > 30), clinically node negative, and the ¹⁸F-FDG PET/CT showed inflammation. Histologic examination showed a positive 2 cm right inguinal metastatic node. The second patient's ¹⁸F-FDG PET/CT showed a suspicious 1 cm left inguinal node. Histologically, the suspicious lymph node was positive for SCCA as was a second positive 2 cm lymph node not identified on preoperative ¹⁸F-FDG PET/CT. Clinical exam of this patient was negative. The third patient was ¹⁸F-FDG PET/CT and clinically negative but subsequently developed a palpable lymph node approximately 1 month later, which was suspicious on repeat ¹⁸F-FDG PET/CT and positive for SCCA on histological examination.Conclusions¹⁸F-FDG PET/CT has shown initial promise in the staging of penile SCCA. However, our review shows that false negative studies occur at alarmingly high rates, and ¹⁸F-FDG PET/CT is poor in detection of micro-metastasis. Thus, close follow-up in these patients is imperative.     

Role of PET/CT in muscle-invasive bladder cancer

The purpose of this study covered the diagnostic accuracy and usefulness of positron emission tomography/computed tomography (PET/CT) imaging in muscle invasive bladder cancer patients through previously published literature. Through 30 September, 2019, the PubMed database was searched for eligible articles that evaluated PET/CT imaging in bladder cancer patients. In general, FDG PET/CT, the most commonly used PET/CT imaging, does not show good performance for the detection of primary lesions; however, according to the literature it could accurately assess pelvic lymph node (LN) status better than other imaging technologies and it was especially helpful in determining extra-pelvic recurrences. More recently, non-FDG PET/CT imaging, such as C-11 acetate and C-11 choline, has been introduced. Although further research is required, preliminary results show the potential of these techniques to overcome the drawbacks of FDG. This concise study will overview the role of PET/CT when treating muscle-invasive bladder cancer (MIBC).     

Final analysis of a prospective trial on functional imaging for nodal staging in patients with prostate cancer at high risk for lymph node involvement

PurposeAccurate staging modalities to diagnose lymph node involvement in patients with prostate cancer (PCa) are lacking. We wanted to prospectively assess sensitivity, specificity, and positive predictive value (PPV) and negative predictive value of ¹¹C-choline positron emission tomography (PET)-computed tomography (CT) and diffusion-weighted (DW) magnetic resonance imaging (MRI) for nodal staging in patients with PCa at high risk for lymph node involvement.Material and methodsIn total, 75 patients with a risk≥10% but<35% for lymph node (LN) metastases (Partin tables) who had N0 lesions based on the findings of contrast-enhanced CT scans were included. Patients underwent ¹¹C-choline PET-CT and DW MRI before surgery, which consisted of a superextended lymph node dissection followed by radical prostatectomy. LNs were serially sectioned and histopathologically examined after pankeratin staining. These results were used as the gold standard to compare with the imaging results.ResultsOf 1,665 resected LNs (median = 21, range: 7–49), 106 affected LNs (median = 2, range: 1–10) were found in 37 of 75 patients (49%). On a region-based analysis, we found a low sensitivity of 8.2% and 9.5% and a PPV of 50.0% and 40.0% for ¹¹C-choline PET-CT and DW MRI, respectively. The patient-based analysis showed a sensitivity of 18.9% and 36.1% for and a PPV of 63.6% and 86.7% ¹¹C-choline PET-CT and DW MRI, respectively. Even when both imaging modalities were combined, sensitivity values remained too low to be clinically useful.ConclusionsBecause of the low sensitivity, there is no indication for routine clinical use of either ¹¹C-choline PET-CT or DW MRI for LN staging in patients with PCa, in whom CT scan findings were normal.     

<Superscript>99m</Superscript>Tc-HDP bone scintigraphy and <Superscript>18</Superscript>F-sodiumfluoride PET/CT in primary staging of patients with prostate cancer

Introduction/Aim

Correct staging of patients with prostate cancer is important for treatment planning and prognosis. Although bone scintigraphy with ^99mTc-phosphonates (BS) is generally advised for staging by guidelines in high risk prostate cancer, this imaging technique is hampered by a high rate of inconclusive results and moderate accuracy. Potentially better imaging techniques for detection of bone metastases such as ¹⁸F-sodiumfluoride PET/CT (NaF PET/CT) are therefore being evaluated. In this observational cohort study we evaluate the performance and clinical impact of both BS and NaF PET/CT in primary staging of patients with prostate cancer.

Methods

The first of two cohorts consisted of patients who received a BS while the second included patients who received a NaF PET/CT for primary staging of prostate cancer. For both cohorts the number of positive, negative and equivocal findings, calculated diagnostic performance of the imaging modality in terms of sensitivity and specificity, as well as the impact on clinical management were studied. The ranges of the diagnostic performance were calculated both assuming that equivocal findings were positive and assuming that they were negative for bone metastases. For the NaF PET/CT cohort the number of patients with signs of lymph node metastases on low dose CT were also recorded, including the impact of these findings on clinical management.

Results

One-hundred-and-four patients underwent NaF PET/CT, whereas 122 patients underwent BS. Sensitivities of 97–100 and 84–95% and specificities of 98–100 and 72–100% were found on a patient basis for detection of bone metastases with NaF PET/CT and BS, respectively. Equivocal findings warranted further diagnostic procedures in 2% of the patients in the NaF cohort and in 16% in the BS cohort. In addition NaF PET/CT demonstrated lymph node metastases in 50% of the included patients, of which 25% showed evidence of lymph node metastases only.

Conclusion

Our data indicate better diagnostic performance of NaF PET/CT compared to BS for detection of bone metastases in primary staging of prostate cancer patients. Less equivocal findings are encountered with NaF PET/CT. Moreover, NaF PET/CT has additional value over BS since lymph node metastases are encountered frequently.