Increasing rate of positive margins in men with high-risk prostate cancer undergoing radical prostatectomy

Abstract

Purpose/Objective(s): The optimal management of men with high-risk prostate cancer (HRPC) is controversial. Currently, the National Comprehensive Cancer Network (NCCN) recommends external beam radiation therapy (EBRT) with androgen deprivation therapy (ADT) or radical prostatectomy (RP). Men with HRPC who undergo RP have an increased risk for positive margins and/or pT3 disease. This may lead to higher rates of adjuvant or salvage RT, which has been shown to have negative influences on urinary function, potency, and quality-of-life. We therefore sought to identify trends and predictors of positive margins in men with HRPC undergoing RP. Materials/Methods: We performed a retrospective analysis of the National Cancer Data Base from 2010 to 2014. We included men with non-metastatic HRPC (T3a or Gleason 8-10 on preoperative needle biopsy or PSA 20) who underwent RP. Information on preoperative Gleason score is only available from 2010 and onward. We performed univariable and multivariable logistic regression to evaluate temporal trends in rates of positive margins over the study period. Two-level hierarchical logistic regression was used to identify covariates associated with positive margins. Patients were clustered within treatment facilities to account for individual facility practice patterns. Results: We identified 58,084 men with HRPC who underwent RP between 2010 and 2014. During this study period, the use of robotic prostatectomy increased from 65% to 78% (P < 0.001). The rate of positive margins increased from 21% to 25% (P < 0.001). On hierarchical multivariable logistic regression, Gleason 9 vs. Gleason 6 (OR Z 2.97, P < 0.001) and Gleason 10 vs. Gleason 6 (OR Z 3.91, P < 0.001) were most strongly associated with positive margins. The proportion of men with Gleason 9 -10 disease who underwent RP increased from 16% to 25% over the study period. Other significant covariates associated with increased odds of positive margins included PSA >10-20 (OR Z 1.61, P < 0.001) or >20 (OR Z 2.04, P < 0.001) vs. PSA 10 and T3-T4 vs. T2 disease (OR Z 1.81, P < 0.001). Academic facility vs. community facility (OR Z 0.78, P Z 0.005) and robotic (OR Z 0.88, P Z 0.007) or laparoscopic (OR Z 0.67, P < 0.001) vs. open prostatectomy were associated with decreased offs of positive margins. Nineteen percent of the total variance was explained by inter-facility variation. Conclusion: From 2010 to 2014, the proportion of men with HRPC undergoing RP with positive margins increased by 19%, and the proportion of men with Gleason 9-10 disease undergoing RP increased by 56%. Significant practice variation was observed. Given that adjuvant EBRT is often recommended for positive margins, men with HRPC choosing RP upfront should be counseled on the potential need for additional treatment that may negatively impact quality-of-life.

MRI validation of Post-Prostatectomy Radiotherapy Contouring

“…External beam radiation is often prescribed after surgery, as either adjuvant or salvage, to improve outcome in patients with positive margins and/or pT3 disease. From 2010 to 2014, the proportion of men with Gleason 9-10 disease undergoing RP has increased by 56% and the incidence of positive margins has increased by 19% [3], thus increasing the need for effective adjuvant/salvage radiotherapy.…”