Purpose: The effect of local and regional treatment on the development of distant metastases in patients with localized node negative and node positive carcinoma of the prostate is examined.
Methods and materials: Distant metastases-free survival was evaluated in 1078 patients with Stage B-C node negative (733 patients) or node positive (345 patients) carcinoma of the prostate, staged with pelvic lymph node dissection and treated with retropublic 125I implantation at the Memorial Sloan-Kettering Cancer Center between 1970 and 1985.
Results: The 15-year actuarial distant metastases-free survival rate for the entire group of patients was 27%. Lymph node involvement was the most significant covariate affecting distant metastases-free survival, although local failure, stage, and grade were also independent variables. Distant metastases-free survival varied with the extent of lymph node involvement (N0 vs. N1, p < 0.0001; N1 vs. N2, p < 0.0001). However, the difference between N1 and N2 patients was due to a faster rate of development of distant metastases in N2 patients. The ultimate 10-year distant metastases-free survival rate was similar for the two patient groups (11% for N1 and 9% for N2). Local failure correlated with the metastatic outcome in patients with B-C/N0 disease (p < 0.00001), but not in N1 or N2 patients. Although distant metastases-free survival in locally controlled N1 patients was improved compared to N2 patients (p = 0.004), when stratified by primary tumor stage and grade, the differences were no longer significant.
Conclusion: Essentially all node positive patients with carcinoma of the prostate will develop distant metastatic disease if followed for sufficiently long periods of time. This is consistent with the hypothesis that in such patients distant micrometastatic dissemination already exists at the time of initial diagnosis. The data suggest that clinical trials designed to test whether improvements in local therapy impact on survival should be restricted to node negative patients. The data also raise concerns regarding the therapeutic value of elective whole pelvic irradiation.