BACKGROUND

Positive surgical margin (PSM) following radical prostatectomy for pT2 prostate cancer is considered a surgical quality metric. We evaluated patient, institutional, surgical approach and cancer-specific factors associated with PSM variability.

Methods

A total of 45,426 men from 1,152 institutions with pT2 prostate cancer following radical prostatectomy were identified using the National Cancer Database (2010-2015). Patient demographics and comorbidity, socioeconomic status, and institutional information, cancer-specific variables and type of surgical approach were extracted. Multilevel hierarchical mixed effects logistic regression model was performed to determine the factors associated with a risk of PSM and their contribution to a PSM status.

Results
Median PSM rate of 8.5% (IQR: 5.2-13.0%, range: 0-100%). Robotic (OR: 0.90, 95% CI: 0.83-0.99) and laparoscopic (OR: 0.74, 95% CI: 0.64-0.90) surgical approach, academic institution (OR: 0.87, 95% CI: 0.76-1.00) and high institution surgical volume (>297 cases [OR: 0.83, 95% CI: 0.70-0.99) were independently associated with a lower PSM. Black men (OR: 1.13, 95% CI: 1.01-1.26) and adverse cancer specific features (PSA 10-20, PSA >20, cT3 stage, Gleason 7, 8, 9-10; all p>0.01) were independently associated with a higher PSM. Multilevel hierarchical logistic regression model accounted for 24.9% of PSM variation. Patient-specific, institution-specific and cancer-specific factors accounted for 2.3%, 3.9% and 15.6% of the variation.

Conclusion
Cancer-specific factors account for 15.2% of PSM variation with the remaining 84.8% of PSM variation due to patient, institution and other factors. Non cancer-specific factors represent potentially addressable factors which are important for policy makers in their efforts to improve patient outcome.