Retrospective comparison of radical retropubic prostatectomy and 125iodine brachytherapy for localized prostate cancer

Purpose: Favorable results with (125)iodine (I) brachytherapy have been reported in select patients with localized prostate cancer. We evaluate the results of radical prostatectomy in patients matched for similar pretreatment clinicopathological characteristics. Materials and Methods: From May 1983 to April 1998, 1 surgeon (W. J. C.) performed radical retropubic prostatectomy in 1,952 men (mean age plus or minus standard deviation 63 +/- 7 years), of whom 1,364 had Gleason score 6 or less on preoperative needle biopsy, a preoperative serum prostate specific antigen (PSA) value available and clinical stage T1 or T2 disease. We categorized all patients by preoperative Gleason score, preoperative PSA and clinical stage. For each Gleason score-by-PSA stratum we randomly selected by computer the number of men necessary to achieve the same overall distribution of clinical characteristics as in a series of patients treated with brachytherapy. All men were followed with semiannual PSA measurements and annual digital rectal examinations. Serum PSA greater than 0.3 ng./ml. was considered evidence of cancer recurrence. Simple univariate statistics were used to compare clinical characteristics between series, and 7-year recurrence-free survival was estimated using Kaplan-Meier product limit estimates. To avoid a possible chance extreme result from 1 random sample we estimated 7-year recurrence-free survival in 5 computer selected random samples of our population. Results: Mean 7-year recurrence-free survival was 84% (95% confidence intervals 78 to 89) for the radical prostatectomy series compared to 79% (confidence intervals not provided) for the I-125 brachytherapy series. Conclusions: Radical prostatectomy yielded a proportionately but not statistically significant higher 7-year probability of nonprogression than I-125 brachytherapy in patients with favorable clinicopathological characteristics. Comparisons are confounded by residual differences in clinicopathological features of tumors between groups and different treatment end points to determine outcomes. Further prospective, randomized clinical trials are required for valid comparisons.