Predicting survival of patients with node-positive prostate cancer following multimodal treatment.
Background: According to the TNM staging system, patients with prostate cancer (PCa) with lymph node invasion (LNI) are considered a single-risk group. However, not all LNI patients share the same cancer control outcomes.
Objective: To develop and internally validate novel nomograms predicting cancer-specific mortality (CSM)-free rate in pN1 patients.
Methods: We evaluated 1107 patients with pN1 PCa treated with radical prostatectomy, pelvic lymph node dissection, and adjuvant therapy at two tertiary care centers between 1988 and 2010. Methods: Univariable and multivariable Cox regression models tested the relationship between CSM and patient clinical and pathologic characteristics, which consisted of prostate-specific antigen (PSA) value, pathologic Gleason score, pathologic tumor stage, status of surgical margins, number of positive lymph nodes, and status of adjuvant therapy. A Cox regression coefficient-based nomogram was developed and internally validated.
Conclusions: All 1107 patients received adjuvant hormonal therapy (aHT). Additionally, 35% of patients received adjuvant radiotherapy (aRT). The 10-yr CSM-free rate was 84% in the entire cohort and 87% in patients treated with aRT plus aHT versus 82% in patients treated with aHT alone (p=0.08). At multivariable analyses, PSA value, pathologic Gleason score, pathologic tumor stage, surgical margin status, number of positive lymph nodes, and aRT status were statistically significant predictors of CSM (all p ≤ 0.04). Based on these predictors, nomograms were developed to predict the 10-yr CSM-free rate in the overall patient population and in men with biochemical recurrence. These models showed high discrimination accuracy (79.5-83.3%) and favorable calibration characteristics. These results are limited by their retrospective nature. Conclusions: Some patients with pN1 PCa have favorable CSM-free rates at 10 yr. We developed and internally validated the first nomograms that allow an accurate prediction of the CSM-free rate in these patients at an individual level.