CONFORMAL EXTERNAL-BEAM TREATMENT OF PROSTATE-CANCER

Objectives. This study reports the 5-year outcomes of treatment for pa tients with prostate cancer treated largely with conformal three-dimen sional radiation therapy. Methods. Results are presented for 456 conse cutive patients treated prior to December 31, 1993 whose pretreatment prostate-specific antigen (PSA) levels are known. Biochemical failure was defined as two consecutive rises in the PSA that equals or exceeds 1.5 ng/mL. Kaplan-Meier product limit methods, the log-rank test, and Cox regression models were used in evaluating the data. No patient wa s lost to follow-up. Results. The 5-year biochemically free of failure (bNED) rate for all patients was 61% and 57% at 7 years. In the group with pretreatment PSA less than 10 ng/mL, the 5-year bNED rate for pa tients with localized disease (T1,2AB disease, Gleason sum of 6 or les s) was 85% and for those with locally advanced disease (T2C,3), 70%. I n the group with pretreatment PSA of 10 to 19.9 ng/mL, the 5-year bNED rate for patients with localized disease was 66% and for those with l ocally advanced disease, 44%. in the group with pretreatment PSA of 20 ng/mL or above, the patients with localized: or locally advanced dise ase had 5-year bNED rates of 31% and 21%, respectively. Conclusions. T he results of largely conformal three-dimensional external beam treatm ent of localized prostate cancer produced 5-year bNED results that are comparable to recent reports of nerve-sparing prostatectomy. Prelimin ary 7-year bNED results in all patients and in patients with localized tumors indicated a modest decrease in the cancer-free rate from that observed at 5 years, suggesting the results are durable. (C) 1997, Els evier Science Inc. All rights reserved.