Abbey Bennett

Incidence and Pathological Features of Prostate Cancer Detected on Transperineal Template Guided Mapping Biopsy After Negative Transrectal Ultrasound Guided Biopsy

PURPOSE We determined the incidence of cancer detection by transperineal template guided mapping biopsy of the prostate in patients with at least 1 previously negative transrectal ultrasound guided biopsy. MATERIALS AND METHODS From January 2005 to January 2012 at least 1 negative transrectal ultrasound guided biopsy was done in 485 patients in our clinical database before proceeding with transperineal template guided mapping biopsy. No study patient had a previous prostate cancer diagnosis. The incidence of patients with 1, 2, or 3 or greater previous transrectal ultrasound guided biopsies was 55.3%, 25.9% and 18.8%, respectively. Transperineal template guided mapping biopsy was done in 74.8% of patients for increasing or occasionally persistently increased prostate specific antigen, in 19.4% for atypical small acinar proliferation and in 5.8% for high grade prostatic intraepithelial neoplasia. RESULTS For the entire study population a median of 59 cores was submitted at transperineal template guided mapping biopsy. Cancer was ultimately detected in 226 patients (46.6%) using the transperineal template guided method, including 196 (86.7%) with clinically significant disease according to the Epstein criteria. The most common cancer detection site on transperineal template guided mapping biopsy was the anterior apex. CONCLUSIONS Transperineal template guided mapping biopsy detected clinically significant prostate cancer in a substantial proportion of patients with negative transrectal ultrasound guided biopsy. This technique should be strongly considered in the context of increasing prostate specific antigen with failed confirmation of the tissue diagnosis.

Transperineal template-guided mapping biopsy as a staging procedure to select patients best suited for active surveillance.

Objectives:Patients with clinically insignificant prostate cancer are candidates for active surveillance. However, uncertainty regarding the true extent of disease limits enthusiasm. In this study, we report our initial findings in patients with transrectal ultrasound (TRUS)-detected clinically insignificant prostate cancer undergoing transperineal template-guided mapping biopsy (TTMB) as a staging procedure. Methods:Sixty-four patients who met the Epstein criteria for clinically insignificant prostate cancer underwent TTMB. Each biopsy core position was recorded in 3 dimensions with documentation of location of each positive biopsy core, Gleason score, percentage of involvement of each core, and presence/absence of perineural invasion. Results:Mean pre-TRUS prostate specific antigen was 4.7 ng/mL with a Gleason score of 6 involving a median of 5% of 1 TRUS core. The mean number of TTMB biopsy cores was 58.5, with 6.6 cores positive for malignancy. Ten patients had clinically insignificant prostate cancer (15.7%), 8 had no TTMB-detected cancer (12.5%), and 46 (71.9%) had clinically significant cancer. Of patients with cancer, 37 (66.1%) had bilobar involvement and 25 (44.6%) harbored a Gleason score of ≥7. In a multivariate analysis, tobacco consumption was found to be most closely related to clinically significant disease on TTMB. Conclusions:TRUS biopsy underestimates disease extent and Gleason score in some patients. TTMB provides a more accurate assessment of the presence of aggressive histology.

Diagnostic Performance of Initial Transperineal Template-guided Mapping Biopsy of the Prostate Gland.

Objectives:To evaluate the utility of transperineal template-guided mapping biopsy (TTMB) of the prostate as an initial means of establishing tissue diagnosis. Materials and Methods:A total of 191 consecutive patients underwent TTMB of the prostate using an anatomic-based technique with sampling of 24 regions. All patients had elevated prostate-specific antigen on routine screening which was followed by a confirmatory prostate-specific antigen and none had undergone previous biopsy of the prostate. The locations of cancer involvement were recorded for each patient in an effort to approximate the percentage of men whose cancer would have been missed or Gleason score underestimated on a standard 12-core biopsy. The median number of submitted biopsy cores was 54.0. Results:Of the 191 study patients, 140 (73.3%) were diagnosed with cancer on TTMB. Among these biopsy-positive patients, 124 (88.6%) had clinically significant cancer. Eighty-nine of the biopsy-positive patients (64.6%) had a Gleason score of ≥7. A total of 34 of the 140 diagnosed cancers were identified exclusively in regions that fell outside of the theoretical 12-core biopsy scheme, suggesting that 24.3% of these cancers would have gone undiagnosed in the absence of TTMB. Among the 107 cancers that would have been diagnosed using a 12-core biopsy approach, 18 (16.8%) were upgraded to a Gleason score of ≥7 with mapping biopsy. Conclusions:TTMB appears to provide more detailed information about prostate cancer grade and location compared with standard 12-core biopsy scheme. This information may serve as a baseline reference for image-guided biopsy (ie, magnetic resonance imaging) regimens, may facilitate clinical decision making and aid in the appropriate selection of patients for active surveillance.

Prognostic importance of tobacco use in men receiving definitive prostate brachytherapy.

PURPOSE Several prominent publications have identified an overall association between tobacco use and an increased risk of disease recurrence and disease-specific mortality in prostate cancer patients. The authors explored whether tobacco use adversely impacts treatment outcomes in men treated with permanent interstitial brachytherapy. METHODS AND MATERIALS From April 1995 to August 2008, 2057 patients underwent brachytherapy by a single brachytherapist. Median follow-up was 7.5 years. The role of tobacco use as a prognostic factor for biochemical progression-free survival, cause-specific survival, and overall survival was investigated. Differences in survival between smokers and nonsmokers were compared using Kaplan-Meier curves and log-rank tests. RESULTS Current smokers presented with a lower body mass index (p<0.001), smaller prostate size (p=0.003), younger age (p<0.001), higher prostate-specific antigen level (p=0.002), a trend toward higher percentage biopsy core involvement (p=0.08), higher incidence of perineural invasion (p=0.015), and higher risk disease (p<0.001) than former or nonsmokers. There was no difference in biochemical progression-free survival (p=0.30) or cause-specific survival (p=0.72) at 10 years for smokers compared with nonsmokers. On univariate and multivariate analysis, tobacco use was an adverse risk factor for overall survival (p<0.001). There was no association between smoking and any prostate cancer-specific outcome. CONCLUSIONS Smokers treated with brachytherapy have excellent outcomes and are at no higher risk of treatment failure than men who are nonsmokers.

Transperineal Template-guided Mapping Biopsy Identifies Pathologic Differences Between Very-Low-risk and Low-risk Prostate Cancer: Implications for Active Surveillance.

Objectives: Active surveillance (AS) is increasingly utilized for low-grade prostate cancer with the greatest risk being the possibility of missing a high-grade cancer. We evaluate the role of transperineal template-guided mapping biopsy (TTMB) to select patients for AS. Methods: A total of 131 consecutive, prospectively evaluated men with transrectal ultrasound-guided needle biopsy (TRUS)-diagnosed very low risk (Gleason score ⩽6, ⩽2 positive biopsies, prostate-specific antigen [PSA] density <0.15, and ⩽50% involvement on any core) and low risk (Gleason score ⩽6, clinical stage T1c, and PSA ⩽10 ng/mL) underwent TTMB as a staging procedure. Biopsies were obtained corresponding to 24 regional biopsy locations. For each patient, the location of each positive biopsy core, the number of positive cores, and the percentage involvement of each core were reported. Results: After TTMB, TRUS-detected very–low-risk prostate cancer patients were less likely to be diagnosed with higher Gleason score, were less likely to have bilateral involvement, and had statistically fewer number of positive biopsy cores on TTMB. After TTMB, no cancer, very–low-risk, or low-risk prostate cancer was detected in 60 of 72 (83.3%) and 19 of 59 (32.2%) of patients with very low and low risk, respectively. In multivariate analysis, older age and low risk predicted for higher Gleason score at the time of TTMB. Conclusions: Very–low-risk prostate cancer patients have a significantly lower incidence of Gleason score upgrading than those with low-risk disease. After TTMB, 83.3% of patients with very–low-risk and 32.2% of patients with low-risk disease appear to be outstanding candidates for AS.

Permanent prostate brachytherapy extracapsular radiation dose distributions: analysis of a multi-institutional database.

Purpose Periprostatic brachytherapy doses impact biochemical control. In this study, we evaluate extracapsular volumetric dosimetry following permanent prostate brachytherapy in patients entered in a multi-institutional community database. Material and methods In the database, 4547 patients underwent brachytherapy (3094 – 125I, 1437 – 103Pd and 16 – 131Cs). Using the originally determined prostate volume, a 5 mm, 3-dimensional peri-prostatic anulus was constructed around the prostate (except for a 2 mm posterior margin), and evaluated in its entirety and in 90° segments. Prostate dosimetric parameters consisted of a V100 and D90 while the annular dosimetry was reported as a V100. Results The intraprostatic V100 and D90 for 103Pd, and 125I were statistically comparable when stratified by isotope and/or monotherapy vs. boost. The overall mean V100 for the periprostatic annulus was 62.8%. The mean V100 at the base (51.6%) was substantially less than the apex (73.5%) and midgland (65.9%). In addition, for all patients, the anterior V100 (45.7%) was less than the lateral (68.8%) and the posterior (75.0%). The geometric V100 annular differences were consistent when evaluated by isotope. Overall, the V100 was higher in the 125I cohort. Conclusions The optimal extracapsular brachytherapy dose and radial extent remains unknown, but will prove increasingly important with reductions and/or elimination of supplemental external beam radiation therapy. The large multi-institutional community database demonstrates periprostatic annular doses that are not as robust as those in selected high volume brachytherapy centers, and may be inadequate for optimal biochemical control following monotherapeutic brachytherapy, especially in higher risk patients.

Metformin Does Not Predict for Prostate Cancer Diagnosis, Grade, or Volume of Disease After Transperineal Template-guided Mapping Biopsy

Objectives: Previous studies have evaluated whether metformin is associated with prostate cancer incidence and outcomes with conflicting conclusions. In this study, we evaluate the incidence of prostate cancer in diabetic patients treated with and without metformin compared with nondiabetic patients. Materials and Methods: One thousand thirty-four patients underwent transperineal template-guided mapping biopsy secondary to either an elevated prostate-specific antigen (PSA) or a prior biopsy finding of atypical small acinar proliferation/prostatic intraepithelial neoplasia. The cohort included 881 nondiabetic men, 65 diabetic men treated with metformin, and 88 diabetic men not receiving metformin. In metformin-treated patients, the median duration of usage was 6.0 years. Differences in prostate cancer diagnosis, histologic grade, and tumor volume were compared across the 3 cohorts. Results: There was no statistically significant differences discerned between the 3 cohorts in patient age, prebiopsy PSA, prostate volume, PSA density, PSA doubling time, PSA velocity, or the total number of prior transrectal ultrasound biopsy sessions. Five hundred eighty-four patients were diagnosed with prostate cancer. There was no difference in prostate cancer diagnosis (P=0.153), Gleason score (P=0.960), the number of positive biopsy cores (P=0.764), or risk group stratification (P=0.877) between the 3 cohorts. In multivariate analysis, only older age predicted for prostate cancer diagnosis. In terms of Gleason score ≥7, patient age, PSA velocity, and body mass index predicted for more aggressive histology. Neither diabetes, metformin use or duration was of statistical consequence. Conclusion: Metformin did not impact incidence of prostate cancer diagnosis, Gleason score distribution, or volume of disease.

Impact of small prostate size on postimplant prostate dosimetry: Analysis of a large community database

PURPOSE Achieving high-quality permanent interstitial brachytherapy in smaller prostates is thought to be more difficult than in larger glands. This study evaluates 4547 implants in a large community database to test this hypothesis. METHODS AND MATERIALS From January 2003 to October 2010, 4547 prostate brachytherapy implants from a large community database were analyzed. The cohort was divided into three groups based on size, namely smaller (<30cm(3), n=1301), medium (30-40cm(3), n=1861), and large (>40cm(3), n=1385). Postimplant dosimetry, including D90, V100, and V100 by prostate sector, was performed for each implant. Comparison of mean V100 among small, medium, and larger prostate volume cohorts was performed using a one-way analysis of variance test. RESULTS For the overall cohort, the D90 was 105% and 104% for monotherapy and boost, respectively. Mean D90 for small prostates was 106% and 104% for monotherapy and boost, respectively. Mean V100 for small prostates was 91.1% and 90.0%, respectively. Coverage for small prostates was as good or slightly better than larger glands. V100 by prostate sector revealed that there were no sectors for which smaller glands had significantly inferior coverage compared with larger glands. CONCLUSION Although smaller prostates may in some respects be more technically difficult to implant than larger glands, a review of community-based brachytherapists reveals that with current implant techniques, good quality implants are readily achievable in men with smaller glands.