Tumor control in definitive irradiation of localized carcinoma of the prostate

Abstract

At the Mallinckrodt Institute of Radiology, Washington University, 343 patients with carcinoma of the prostate were treated with definitive radiotherapy. All patients are available for minimal 3 year follow-up; the median period of observation is 5.2 years. The incidence of pelvic recurrence with or without distant metastases was 0% in 10 patients with Stage A 2,11% in 113 patients with Stage B, 34% in 204 patients with Stage C, and 40% in 16 patients with Stage D1. There was no significant difference in pelvic tumor control when correlated with the degree of differentiation of the tumors in each stage. In Stage B, patients who exhibited complete regression 3 months after completion of therapy had a pelvic failure rate of 5%, those with 50–75% regression-8% and less than 50% regression—18%. In Stage C, patients with more than 50% tumor regression had a pelvic failure rate of 25%, in contrast to 37% when less than 50% regression was noted at 3 months after completion of irradiation. However, there was no correlation between tumor regression and NED survival. In patients with Stage B, there was no significant correlation between doses of irradiation ranging from 6000 to 7000 cGy and pelvic tumor control. In Stage C, patients receiving doses higher than 6500 cGy had a probability of failure rate in the pelvis of 25% ( 40 173 ), in comparison with 44% with doses between 6000–6500 cGy (15/32). The 10 year NED survival for Stage A 2 was 100%, Stage B-70%, and Stage C-40%. In Stage B, there was no correlation between local tumor control and 5 year overall survival. However, at 10 years 88 patients without evidence of local failure or distant metastases had a survival rate of 70% in contrast to only 25% if they recurred. In Stage C, 110 patients without local recurrence or distant metastases had a 40% 10 year survival in contrast to 20% in 55 patients who had pelvic recurrence (with or without distant metastases) and 39 patients with distant metastases only. In 105 patients with Stage B tumor controlled in the pelvis, the incidence of distant metastases was 16%, in contrast to 50% in eight patients with pelvic failure. In Stage C, only 26% of 149 patients with pelvic tumor controlled developed distant disease, versus 60% in 55 patients failing in the pelvis. Ninety-five percent of the pelvic failures and 80% of the distant metastases appeared within 5 years after therapy. The administration of hormones did not significantly influence either the probability of pelvic tumor control or the appearance of distant metastases.