MRT-navigierte stereotaktische Prostatabiopsie

Background

A key challenge for prostate cancer (PC) therapy is to exactly diagnose tumor lesions. In this context we describe a new stereotactic prostate biopsy system, which integrates pre-interventional MRI with peri-interventional ultrasound for targeted perineal prostate biopsies. Furthermore, the novel system allows exact documentation of biopsies in three dimensions.

Patients and methods

Stereotactic biopsy was performed in 50 consecutive men with suspicion of PC [median age 67?years (42?C77), mean PSA 8.9±6.8?ng/ml, and mean prostate volume 51±23.7?ml]. Twenty-five of these patients (50%) had already had a negative transrectal ultrasound (TRUS)-guided biopsy. All men underwent multiparametric, contrast-enhanced 3T MRI without endorectal coil. Suspicious lesions were marked before the obtained data were transferred to a novel stereotactic biopsy system. Using a custom-made biplane TRUS probe mounted on a stepper, 3-D ultrasound data were generated and fused with the MRI. As a result, suspicious MRI lesions were superimposed onto the TRUS data. Next, 3-D biopsy planning was performed including systematic biopsies from the peripheral zone of the prostate. According to local standards patients were treated with perioperative quinolone antibiotics and applied a rectal enema the evening before the procedure. Perineal biopsies were taken under live US imaging, and the location of each biopsy was documented in an individual 3-D model. Feasibility, safety, target registration error, and cancer detection were evaluated.

Results

The median number of biopsies taken per patient was 24 (12?C36). In 27 men of the initial cohort of 50 consecutive patients presented here, biopsy samples showed PC (54%). In patients undergoing their first biopsy, cancerous lesions were diagnosed in 13 of 19 patients (68%). The result was positive in 36% of men undergoing a re-biopsy without previous cancer diagnosis (9/25). A positive correlation between MRI findings and histopathology was found in 72%. In MRI lesions marked as highly suspicious, the tumor detection rate was 100% (13/13). Looking at single cores from highly suspicious lesions, 40 of 75 (53%) biopsies were positive. The target registration error of the first 1,159 biopsy cores was 1.7?mm. Regarding adverse effects, one patient experienced urinary retention and one patient a perineal hematoma. Urinary tract infections did not occur.

Conclusion

Perineal stereotactic prostate biopsies guided by the combination of MRI and ultrasound allow effective examination of suspicious MRI lesions. Each biopsy core taken is documented accurately for its location in 3-D enabling MRI validation and tailored treatment planning. The morbidity of the procedure was minimal.     

Innovations in diagnostic imaging of localized prostate cancer

Purpose

In recent years, various imaging modalities have been developed to improve diagnosis, staging, and localization of early-stage prostate cancer (PCa).

Methods

A MEDLINE literature search of the time frame between 01/2007 and 06/2013 was performed on imaging of localized PCa.

Results

Conventional transrectal ultrasound (TRUS) is mainly used to guide prostate biopsy. Contrast-enhanced ultrasound is based on the assumption that PCa tissue is hypervascularized and might be better identified after intravenous injection of a microbubble contrast agent. However, results on its additional value for cancer detection are controversial. Computer-based analysis of the transrectal ultrasound signal (C-TRUS) appears to detect cancer in a high rate of patients with previous biopsies. Real-time elastography seems to have higher sensitivity, specificity, and positive predictive value than conventional TRUS. However, the method still awaits prospective validation. The same is true for prostate histoscanning, an ultrasound-based method for tissue characterization. Currently, multiparametric MRI provides improved tissue visualization of the prostate, which may be helpful in the diagnosis and targeting of prostate lesions. However, most published series are small and suffer from variations in indication, methodology, quality, interpretation, and reporting.

Conclusions

Among ultrasound-based techniques, real-time elastography and C-TRUS seem the most promising techniques. Multiparametric MRI appears to have advantages over conventional T2-weighted MRI in the detection of PCa. Despite these promising results, currently, no recommendation for the routine use of these novel imaging techniques can be made. Prospective studies defining the value of various imaging modalities are urgently needed.     

Standardisierung des multiparametrischen 3-T-MRT zur zielgerichteten Biopsie der Prostata

Background

The use of multi-parametric MRI and MRI-guided biopsy for the detection of prostate cancer is rapidly increasing. This is a pilot study to evaluate the consensus-based international MRI scoring system as decision criterion for targeted MRI-guided prostate biopsy.

Material and methods

After a multi-parametric 3-T MRI (T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced MRI) in 23 consecutive patients a total of 47 lesions were scored according to a 5-point scale for each MRI sequence. A total score of ≥10 points was considered to be suspicious for prostate cancer. All 47 lesions were histologically assessed after MRI-guided biopsy.

Results

At the cut-off score of 10 points, sensitivity, specificity, negative predictive value and positive predictive value of multi-parametric MRI were 94.1, 43.3, 92.9 and 48.5%, respectively.

Conclusions

A standardised scoring of lesions on multi-parametric MRI is feasible. The cut-off value leads to excellent values for sensitivity and negative predictive value. The values for specificity and positive predictive value are modest. Lesions with a total score <10 points are very unlikely to be malignant.     

Endorectal magnetic resonance imaging and spectroscopy for the detection of tumor foci in men with prior negative transrectal ultrasound prostate biopsy

Purpose

We determined the ability of combined endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) to detect prostate cancer foci prospectively in men with prior negative transrectal ultrasound (TRUS) prostate biopsy.

Materials and Methods

Endorectal MRI with spectroscopy was performed in 24 consecutive patients with 1 or more prior negative TRUS prostatic biopsies for persistently increased prostate specific antigen and/or abnormal digital rectal examination. All studies were interpreted by a dedicated radiologist who reported areas of interest in the peripheral zone as normal, equivocal or suspicious on MRI and MRSI separately. Equivocal and suspicious areas were then correlated with a 3-dimensional prostate model. All patients underwent a standard TRUS 10-core peripheral zone biopsy with up to 4 additional biopsies targeted at the equivocal or suspected sites.

Results

Prostate cancer was detected in 7 of 24 subjects (29.2%). Considering the equivocal category as test negative the sensitivity, specificity, positive and negative predictive values, and the accuracy of MRI, MRSI and combined MRI/MRSI for the detection of prostate cancer were 57.1%, 57.1% and 100.0%, 88.2%, 82.4% and 70.6%, 66.7%, 57.1% and 58.3%, 83.3%, 82.1% and 100%, and 79.2%, 75.0% and 79.2%, respectively. The site of positive biopsy correlated correctly in 50% and 28.6% of MRI and MRSI labeled suspicious cores, respectively.

Conclusions

MRI and MRSI have the potential to identify cancer foci and direct TRUS in patients with a previous negative TRUS biopsy. Further, larger studies are required to quantify the amount of benefit.     

Prostate cancer detected after Holmium laser enucleation of prostate (HoLEP): significance of transrectal ultrasonography

Purpose

To identify predictors of incidental prostate cancer following Holmium laser enucleation of the prostate (HoLEP).

Methods

We retrospectively analyzed 458 consecutive patients who underwent HoLEP. Patients were classified into two groups: patients who received prostate biopsy prior to HoLEP (biopsy group, n = 174) and patients who did not (non-biopsy group, n = 284). The two groups were compared. Logistic regression analysis was performed to determine the predictive factors.

Results

A total of 27 patients (5.9 %) were incidentally diagnosed with prostate cancer. The incidence of prostate cancer was not significantly different between the two groups (biopsy group vs. non-biopsy group: 6.9 vs. 5.3 %, p = 0.48). Using multivariate analysis, a hypoechoic lesion identified by transrectal ultrasonography (TRUS) was the only predictor of incidental prostate cancer (odds ratio 2.829; 95 % confidence interval 1.061–7.539; p = 0.038). In the biopsy group, there were no significant differences in baseline characteristics including prostate size, prostate-specific antigen (PSA), PSA density, digital rectal examination (DRE) findings, and TRUS findings, between patients with and without prostate cancer. However, in the non-biopsy group, a hypoechoic lesion was found more frequently in patients with prostate cancer (prostate cancer vs. benign prostatic hyperplasia: 20.0 vs. 3.3 %, p = 0.02).

Conclusions

Prior negative prostate biopsy does not rule out the possibility of prostate cancer after HoLEP. The presence of a hypoechoic lesion on TRUS might be helpful to predict incidental prostate cancer after HoLEP in patients with normal PSA and negative DRE. Prostate biopsy prior to HoLEP should be considered in these patients.     

Evolution of repeat prostate biopsy strategies incorporating transperineal and MRI–TRUS fusion techniques

Purpose

To test the hypothesis that MRI–TRUS fusion technique can increase the detection rate of prostate cancer (PC) in patients with previously negative biopsy.

Methods

Patient records of men with persisting suspicion for PC after previous negative biopsy having undergone either extensive transrectal prostate biopsies (MD Anderson protocol; MDA), transperineal saturation (STP) or magnetic resonance imaging (MRI)/transrectal ultrasound (TRUS) fusion transperineal biopsies (MTTP) in three consecutive time intervals were reviewed retrospectively. The respective approach was the standard for the above indication at these episodes. In Cambridge, 70 patients underwent MDA biopsies, 75 STP underwent biopsies and 74 patients underwent MTTP biopsies. In total, 164 MTTP patients with the same indication from Heidelberg were analysed as reference standard. In total, 383 men were included into analysis. Low-grade PC was defined as Gleason score 7 (3 + 4) or lower.

Results

Even though MTTP patients had significantly larger prostates, the overall cancer detection rate for PC was the highest in MTTP (24.2 % MDA, 41.3 % STP, 44.5 % MTTP, p = 0.027, Kruskal–Wallis test). The detection rate for clinically relevant high-grade PC was highest in MTTP; however, this did not reach statistical significance compared with MDA (23.5 % MDA, 12.9 % STP, 27.2 % MTTP, p = 0.25, Fischer’s exact test). Comparing MTTP between Cambridge and Heidelberg, detection rates did not differ significantly (44.5 vs. 48 %, p = 0.58). There was a higher detection rate of high-grade cancer in Heidelberg. (36.3 vs. 27.2 %, p = 0.04).

Conclusion

Patients whom are considered for repeat biopsies may benefit from undergoing MRI-targeted TRUS fusion technique due to higher cancer detection rate of significant PC.     

Does periprostatic local anesthesia for prostate biopsy affect the operative difficulty of open radical prostatectomy? A prospective randomized trial

Objectives

Periprostatic local anesthesia for transrectal ultrasound (TRUS)-guided prostate biopsy requires additional needle punctures and injection of local anesthetics into the periprostatic area. This study sought to determine the influence of periprostatic local anesthesia on the surgical difficulty of open radical prostatectomy (RP).

Patients and methods

A total of 241 consecutive patients who underwent TRUS-guided prostate needle biopsy were randomized to receive either periprostatic nerve block (Anesthesia group; n?=?120) or no anesthesia (Control group; n?=?121). After diagnosing localized prostate cancer, patients who underwent open RP without neoadjuvant androgen deprivation therapy were evaluated as to whether perioperative nerve block affected operative duration, estimated blood loss (EBL), positive margin rate or complications.

Results

Twenty-one patients in the Anesthesia group and 19 patients in the Control group were investigated in the current study. In assessing the patients who underwent open RP with or without periprostatic nerve block, no significant differences in operative duration, EBL, positive margin rate or complications were seen between groups.

Conclusion

Periprostatic nerve block does not appear to affect perioperative outcomes after open RP.     

3D Navigo™ versus TRUS-guided prostate biopsy in prostate cancer detection

Introduction

To overcome the limitations regarding transrectal ultrasound (TRUS)-guided biopsies in prostate cancer (PCa) detection, there is a focus on new imaging technologies. The Navigo? system (UC-care, Israel) uses regular TRUS images and electrospatial monitoring to generate a 3D model of the prostate. The aim of this study was to compare cancer detection rates between the Navigo? system and conventional TRUS, in patients without a history of PCa.

Methods

We performed a retrospective study by collecting data from all patients who underwent 12-core prostate biopsies from lateral peripheral zones between September 2013 and February 2015 at the Jeroen Bosch Hospital in ‘s-Hertogenbosch (Netherlands).

Results

A total of 325 patients met our inclusion criteria. 77.8 % of biopsy sessions were performed using the Navigo? system. There was no statistically significant difference in PCa detection (39.9 vs 46.2 % with Navigo? system and TRUS, respectively). Using the Navigo? system for taking prostate biopsies proved not to be associated with the presence of PCa at biopsy, likewise for clinically significant PCa and for both subgroups.

Limitations

The limitations of the study include its retrospective design, the limited number of patients in the conventional TRUS group, the statistically significant different number of biopsy sessions and the ones performed by an advanced physician in both groups.

Conclusion

In our study, there is no added value of 3D TRUS using Navigo? system compared to conventional 2D TRUS regarding PCa detection in biopsy-naive men and men with prior negative biopsy.

     

Transperineal template prostate biopsies in men with raised PSA despite two previous sets of negative TRUS-guided prostate biopsies

Background

The possibility of prostate cancer as a cause for steadily rising PSA despite previously negative transrectal ultrasound (TRUS)-guided prostate biopsies is a major concern. An initial negative TRUS-guided prostate biopsy does not necessarily exclude the presence of clinically significant prostate cancer. We determined the role of transperineal template prostate biopsy (TPTPB) in prostate cancer detection in men with raised PSA despite two previous sets of negative TRUS biopsies.

Methods

Between January 2008 and August 2012, a total of 122 men’s records were reviewed after having 36-core TPTPB following two previous sets of negative TRUS biopsies despite raised PSA. A retrospective record of PSA levels, clinicopathological parameters and histological outcomes was made.

Results

Mean age was 63 years (range 49–77), and mean PSA was 18.0 (range 2.0–119.0). A total of 71/122 (58 %) men were diagnosed with prostate cancer on TPTPB. Of these, 28 (39 %), 34 (48 %), 5 (7 %), and 4 (6 %) had Gleason score 6, 7 (3 + 4), 7 (4 + 3), and 9 (4 + 5), respectively. The mean number of positive cores was 7 (range 1–22). Of these, only 15 (21 %) had ≤2 cores positive and Gleason score of 6. Of the 51 (42 %) men with a negative histology on TPTPB, 11 (22 %), 10 (19 %), and 30 (59 %) had atypical small acinar proliferation, high-grade prostatic intraepithelial neoplasia, or benign pathology.

Conclusion

TPTPB is associated with a high rate of clinically significant prostate cancer diagnosis (58 %) in men with raised PSA despite two previous sets of negative TRUS biopsies.     

Comparison of image-guided targeted biopsies versus systematic randomized biopsies in the detection of prostate cancer: a systematic literature review of well-designed studies

Objective

The clinical utility of image-targeted biopsies can only be judged by a comparison of the current standard of systematic 10–12 core biopsy schemes. The aim of this review was to gather the current evidence in favor of or against targeted biopsies in the detection of prostate cancer based on well-designed, controlled studies, in order to draw clinical relevant conclusions.

Subjects/patients and methods

A systematic literature review was performed addressing studies that compared the prostate cancer detection rates of targeted and systematic biopsy schemes using the imaging techniques of elastography, contrast-enhanced ultrasound, histoscanning and multiparametric MRI. Only well-designed, controlled studies were included and the results summarized.

Results

All imaging techniques are associated with varying results regarding better or poorer detection rates relative to systematic biopsies. No technique provides a clear trend in favor of or against image-targeted biopsies. In almost all studies, the combination of targeted and systematic biopsies provided sometimes a substantial, increase in the detection rate relative to systematic biopsies alone. MRI-targeted biopsies show no advantage in the initial biopsy setting, whereas in the repeat biopsy setting improvements in the detection rates are often observed relative to systemic biopsies.

Conclusion

Based on well-designed, controlled studies no clear advantage of targeted biopsies over the current standard of systematic biopsies can be observed. Therefore, targeted biopsies cannot replace systematic biopsies in the diagnosis of prostate cancer. In all indications, the combination of systematic and targeted biopsy schemes provides the highest detection rate.     

Current beliefs and practice patterns among urologists regarding prostate magnetic resonance imaging and magnetic resonance–targeted biopsy

Introduction and objective

Multiparametric magnetic resonance imaging (MRI) and magnetic resonance (MR) -targeted biopsy have a growing role in the screening and evaluation of prostate cancer. We aim to evaluate the current knowledge, attitude, and practice patterns of urologists regarding this new technique.

Patient selection determines the prostate cancer yield of dynamic contrast-enhanced magnetic resonance imaging-guided transrectal biopsies in a closed 3-Tesla scanner

OBJECTIVE

To evaluate the cancer yield of transrectal prostate biopsies in a 3‐T magnetic resonance imaging (MRI) scanner in patients with elevated prostate specific antigen (PSA) levels and recent negative transrectal ultrasonography (TRUS)‐guided prostate biopsies.

PATIENTS AND METHODS

Between July 2004 and November 2005, patients with at least one previous negative prostate biopsy within the previous 12 months had MRI‐guided biopsy of the prostate in a 3‐T MRI scanner. Patients with previous positive biopsies for cancer were excluded. Target selection was based on T2‐weighted imaging and dynamic contrast‐enhanced (DCE) imaging studies.

RESULTS

Thirteen patients were eligible; their median (range) age was 61 (47–74) years and PSA value 4.90 (1.3–12.3) ng/mL. Most patients had one previous negative biopsy (range 1–4). Four patients had a family history of prostate cancer. There were 37 distinct targets based on T2‐weighted imaging. Fifteen of 16 distinct DCE abnormalities were co‐localized with a target based on T2‐weighted imaging. Despite this correlation, only one of 13 patients had a directed biopsy positive for cancer. Including systematic biopsies, two of 13 patients had a biopsy positive for prostate cancer. One patient had prostate intraepithelial neoplasia and one had atypical glands in the specimen.

CONCLUSION

The prostate‐cancer yield of transrectal biopsies in a 3‐T MRI scanner, among patients with recent negative TRUS‐guided prostate biopsies, is similar to repeat systematic TRUS‐guided biopsy. DCE correlates with T2‐imaging but does not appear to improve prostate cancer yield in this population.     

Importance of prostate volume in the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculators: results from the prostate biopsy collaborative group

Objectives

To compare the predictive performance and potential clinical usefulness of risk calculators of the European Randomized Study of Screening for Prostate Cancer (ERSPC RC) with and without information on prostate volume.

Methods

We studied 6 cohorts (5 European and 1 US) with a total of 15,300 men, all biopsied and with pre-biopsy TRUS measurements of prostate volume. Volume was categorized into 3 categories (25, 40, and 60?cc), to reflect use of digital rectal examination (DRE) for volume assessment. Risks of prostate cancer were calculated according to a ERSPC DRE-based RC (including PSA, DRE, prior biopsy, and prostate volume) and a PSA?+?DRE model (including PSA, DRE, and prior biopsy). Missing data on prostate volume were completed by single imputation. Risk predictions were evaluated with respect to calibration (graphically), discrimination (AUC curve), and clinical usefulness (net benefit, graphically assessed in decision curves).

Results

The AUCs of the ERSPC DRE-based RC ranged from 0.61 to 0.77 and were substantially larger than the AUCs of a model based on only PSA?+?DRE (ranging from 0.56 to 0.72) in each of the 6 cohorts. The ERSPC DRE-based RC provided net benefit over performing a prostate biopsy on the basis of PSA and DRE outcome in five of the six cohorts.

Conclusions

Identifying men at increased risk for having a biopsy detectable prostate cancer should consider multiple factors, including an estimate of prostate volume.     

Validation and comparison of the two Kattan nomograms in patients with prostate cancer treated with (125) iodine brachytherapy

Study Type – Clinical (prospective trial) Level of Evidence 2b What's known on the subject? and What does the study add? In clinical practice, we know that it is necessary to identify new biomarkers that can better detect prostate cancer (PC), at the same time as reducing the number of unnecessary biopsies. Recently, studies have suggested that the most relevant clinical scenario in which the prostate cancer antigen 3 (PCA3) score could be used comprises patients with a previous negative prostate biopsy and persistently elevated PSA levels. At the same time, although multiparametric MRI is not currently used as a first approach for diagnosing PC, it can be useful for directing targeted biopsies, especially in those patients with elevated PSA levels and a previous negative TRUS‐guided biopsy. Considering all of these aspects, the present study aimed to evaluate the role of multiparametric MRI as an additional diagnostic tool for improving the accuracy of the urinary PCA3 test in patients with increased PSA levels and a previous negative prostate biopsy. Our hypothesis is that the potential value of the PCA3 test as a biomarker for PC diagnosis could be improved by the use of multiparametric MRI in directing prostate biopsy. In the present study, we show that, in cases with a previous negative biopsy and persistently elevated PSA levels submitted to multiparametric MRI to direct biopsies, the sensitivity of the PCA3 test significantly improved (79% vs 68%). However, further larger randomized studies on this combination using a new biomarker and a new imaging modality for PC diagnosis are expected.

OBJECTIVE

• ? To evaluate the role of multiparametric magnetic resonance imaging (MRI) as an additional diagnostic tool for improving the accuracy of the urinary prostate cancer antigen 3 (PCA3) test in patients with an increase in prostate‐specific antigen (PSA) levels and a previous negative prostate biopsy.

PATIENTS AND METHODS

• ? The present study comprised a prospective randomized study on patients with a previous negative transrectal ultrasonography (TRUS)‐guided prostate biopsy and elevated PSA levels.
• ? In total, 180 cases were analyzed, and all were submitted to PCA3 assay.
• ? Patients in group A were submitted to a second random TRUS‐guided prostate biopsy, whereas patients in group B were submitted to a multiparametric MRI examination and then to a second TRUS‐guided prostate biopsy.

RESULTS

• ? At the second biopsy, a histological diagnosis of prostate cancer was found in 26 of 84 cases (30.9%) in group A and in 29 of 84 cases (34.5%) in group B.
• ? In group A, the sensitivity and specificity of the PCA3 score were 68.0% and 74.5% respectively (positive predictive value of 53.1%, negative predictive value of 84.6% and accuracy of 72.6%).
• ? In group B, the sensitivity and specificity of the PCA3 score were 79.3% and 72.7%, respectively (positive predictive value of 60.5%, negative predictive value of 86.9% and accuracy of 75.0%).
• ? For the PCA3 score, the area under the receiver‐operator characteristic curve was 0.825 (95% confidence interval, 0.726–0.899) in group A and 0.857 (95% confidence interval, 0.763–0.924) in group B (P < 0.001).

CONCLUSION

• ? In patients with a previous negative biopsy and persistently elevated PSA levels, the use of multiparametric MRI for indicating sites suitable for rebiopsy can significantly improve the sensitivity of the PCA3 test in the diagnosis of prostate cancer.

     

Predictors of Gleason score upgrading in a large African-American population

Purpose

Gleason score from biopsy specimens is important for prostate cancer (PCa) risk stratification and influences treatment decisions. Gleason score upgrading (GSU) between biopsy and surgical pathology specimens has been reported as high as 50 % and presents a challenge in counseling low-risk patients. While recent studies have investigated predictors of GSU, populations in these studies have been largely Caucasian. We report our analysis of predictors of GSU in a large urban African-American population.

Methods

A total of 959 patients with D’Amico low-risk prostate cancer underwent radical prostatectomy at Georgetown University or Washington Hospital Center between January 2005 and July 2012. Race, age, PSA, body mass index (BMI), cancer of the prostate risk assessment (CAPRA) score, and transrectal ultrasound (TRUS) biopsy characteristics (percent of biopsy cores showing adenocarcinoma, highest percent of biopsy core involved with cancer, and measured TRUS prostate volume) were analyzed with both univariate and multivariate analyses to identify significant predictors of GSU while controlling for clinical parameters.

Results

Of the 959 cases, 288 (30.0 %) were upgraded on final pathologic specimen with approximately 38 % (133/355) of African-American patients experiencing GSU. BMI (P = 0.02), percent positive biopsy cores (P < 0.01) and percent of core involved with cancer (P < 0.01), increasing CAPRA score, and serum PSA were independent predictors of GSU on both uni- and multivariate regression analyses. African Americans had a 73 % increase in the incidence of GSU over other races.

Conclusion

More than a quarter of low-risk prostate cancer patients were upgraded on final pathology in our series. Higher BMI, serum PSA, CAPRA score, percent of cores positive, and percent of cores involved were independent predictors of GSU. Individuals with those clinical parameters may harbor occult high-grade disease and should be carefully counseled on treatment decisions.     

Molekulare Bildgebung in der onkologischen Chirurgie

Background

Diagnostic imaging with positron emission tomography (PET) is becoming increasingly more involved in oncological therapy management.

Objectives

How can PET be helpful in oncological surgery?

Methods

After a short introduction into the basic principles of PET the current state of imaging as well as indications and limitations of the method are described.

Results

The PET is a functional and quantitative imaging technique, enabling detection and characterization of tumors. It is applied in pretherapeutic staging as well as in follow-up and therapy assessment. The use of PET changes the therapy management in about one third of all oncology patients. New radiopharmaceuticals and novel technologies expand the diagnostic potential.

Discussion

Hybrid imaging with PET computed tomography (CT) and PET magnetic resonance imaging (MRI) further improves diagnostic imaging and increases the acceptance of PET further.     

Lesions Originating Within the Retrorectal Space: A Diverse Group Requiring Individualized Evaluation and Surgery

Background

Tumors occurring within the retrorectal space are rare and their low incidence has led to a paucity of literature regarding them.

Methods

Adult patients with retrorectal tumors managed at this institution from 1981–2011 were identified. A retrospective chart review was conducted to obtain relevant data.

Results

Retrorectal tumors were identified in 87 patients (67 female) with median age at diagnosis of 44 years (19–88), and median follow-up 8 months (0.1–225). Of the 25 different histologic tumors diagnosed, hamartomas were most common (32 %; n?=?28) followed by epidermal cysts (11 %; n?=?10), and teratomas (10 %; n?=?9). Twenty-six percent (23/87) of all tumors were malignant. CT scans were obtained in 84 % (73/87) of patients, MRI in 59 % (51/87), and TRUS in 16 % (14/87). While 74 % (64/87) of tumors were at or below the S4 level, operative approach was strictly posterior in 73 % (46/63) of these tumors. Twenty-eight percent (24/87) of patients underwent diagnostic biopsy with no reported biopsy site recurrence. Thirty percent (7/23) of resected malignant (all recurrences: distant) and eleven percent (7/64) of benign tumors (all recurrences: local) recurred. Survival was 70 % (16/23) for malignant tumors and 98 % (63/64) for benign tumors.

Conclusions

Retrorectal tumors remain heterogeneous and a diagnostic challenge. Pre-operative imaging may help guide surgeons; however, malignancy portends worse outcomes. Despite preoperative biopsy site recurrence concerns, no patient in this study had biopsy site recurrence. As their natural history remains unclear, more studies are necessary to further characterize their behavior.     

Improved performance of SPECT-CT In-111 capromab pendetide by correlation with diffusion-weighted magnetic resonance imaging for identifying metastatic pelvic lymphadenopathy in prostate cancer

Purpose

To preliminarily evaluate the potential for an improvement in diagnostic performance by a combined interpretation of In-111 capromab pendetide single photon emission computed tomography (SPECT) including computed tomography (CT) image fusion with magnetic resonance diffusion-weighted imaging (MR-DWI) for identifying prostate cancer in pelvic lymph nodes thru correlation with histopathology.

Materials and methods

This institutional approved, retrospective study identified patients with available histopathology of lymph nodes removed at the time of radical prostatectomy and who had undergone staging with In-111 capromab pendetide SPECT-CT and/or pelvic MRI (including DWI). The performance of In-111 capromab pendetide SPECT for identifying malignant lymph nodes was assessed. Subsequently, a combined reading of In-111 capromab pendetide SPECT and prostate MRI with DWI was performed and the performance assessed.

Results

18 patients underwent In-111 capromab pendetide SPECT-CT. Of these, 12 patients had also undergone imaging with MR-DWI. In-111 capromab pendetide SPECT-CT had a sensitivity of 40.0 % and specificity of 96.7 % for identification of malignant lymph nodes. However, In-111 capromab pendetide SPECT-CT combined with MRI with DWI had a sensitivity of 88.9 % and specificity of 98.5 %.

Conclusions

The addition of MR-DWI to the interpretation of In-111 capromab pendetide SPECT-CT may increase the sensitivity for detecting malignant lymph nodes in prostate cancer. Future prospective evaluation of combined In-111 capromab pendetide SPECT-CT and MR-DWI is indicated and may improve clinical evaluation of nodal disease in prostate cancer.