Survival Outcomes of Men with Lymph Node-positive Prostate Cancer After Radical Prostatectomy: A Comparative Analysis of Different Postoperative Management Strategies.

Background: Optimal management of patients with lymph node metastasis (LNM) after radical prostatectomy (RP) remains undefined.

Objective: We evaluated the association between three different management strategies and survival in prostate cancer with LNM after RP.

Design, Setting, And Participants: We analyzed data of 1338 patients with LNM after RP from three tertiary care centers. Three hundred and eighty-seven patients (28%) were observed, 676 (49%) received lifelong adjuvant androgen deprivation therapy (ADT), and 325 (23%) received adjuvant external beam radiation therapy (EBRT) and ADT. Three hundred and sixty-eight men were followed for more than 10 yr.

Outcome Measurements And Statistical Analysis: Primary outcome measure was overall survival (OS). Secondary outcomes were cancer-specific survival (CSS) and other-cause mortality. Kaplan-Meier methods were used to visualize OS for the three treatment groups. Cox proportional hazards regression was utilized to compare OS and CSS among the three groups.

Results And Limitations: ADT+EBRT was associated with better OS than ADT alone (hazard ratio [HR]: 0.46, 95% confidence interval [CI]: 0.32-0.66, p<0.0001) or observation (HR: 0.41, 95% CI: 0.27-0.64, p<0.0001). Higher-risk patients benefited more from ADT+EBRT than lower-risk patients. Ten-year mortality risk difference between ADT+EBRT, observation, or ADT alone ranged from 5% in low-risk patients to 40% in high-risk patients. Adjuvant ADT+EBRT was also associated with better CSS than observation or ADT alone (p<0.0001), ADT had better CSS compared to observation (HR: 0.64, 95% CI: 0.43-0.95, p=0.027). However, ADT was associated with an increased risk of other-cause mortality (HR: 3.05, 95% CI: 1.45-6.40, p=0.003) compared with observation, resulting in similar OS between ADT and observation (HR: 0.90, 95% CI: 0.65-1.25, p=0.5). While selection bias might remain, its effect would operate in the opposite direction to our findings.

Conclusions: In men with LNM after RP, ADT+EBRT improved survival over either observation or adjuvant ADT alone. This survival benefit increases with higher-risk disease.

Patient Summary: Lymph node metastasis following radical prostatectomy is associated with poor survival outcomes. However, we found that adjuvant androgen deprivation therapy with external beam radiation therapy improved survival in these patients.