Biochemical outcome after radical prostatectomy, external beam radiation therapy, or interstitial radiation therapy for clinically localized prostate cancer

Context. - Interstitial radiation (implant) therapy is used to treat clinically localized adenocarcinoma of the prostate, but how it compares with other treatments is not known. Objective. - To estimate control of prostate- specific antigen (PSA) after radical prostatectomy (RP), external beam radiation (RT), or implant with or without neo-adjuvant androgen deprivation therapy in patients with clinically localized prostate cancer. Design. - Retrospective cohort study of outcome data compared using Cox regression multivariable analyses. Setting and Patients. - A total of 1872 men treated between January 1989 and October 1997 with an RP (n = 888) or implant with or without neoadjuvant androgen deprivation therapy (n = 218) at the Hospital of the University of Pennsylvania, Philadelphia, or RT (n = 766) at the Joint Center for Radiation Therapy, Boston, Mass, were enrolled. Main Outcome Measure. - Actuarial freedom from PSA failure (defined as PSA outcome). Results. - The relative risk (RR) of PSA failure in low-risk (stage T1c, T2a and PSA level ≤ 10 ng/mL and Gleason score ≤ 6) treated using RT, implant plus androgen deprivation therapy, or implant therapy was 1.1 (95% confidence interval [Cl], 0.5-2.7), 0.5 (95% Cl, 0.1-1.9), and 1.1 (95% Cl, 0.3-3.6), respectively, compared with those patients treated with RP. The RRs of PSA failure in the intermediate-risk patients (stage T2b Gleason score of 7 or PSA level > 10 and ≤ 20 ng/mL) and high-risk patients (stage T2c or PSA level > 20 ng/mL or Gleason score ≤ 8) treated with implant compared with RP were 3.1 (95% Cl, 1.5-6.1) and 3.0 (95% Cl, 1.8-5.0), respectively. The addition of androgen deprivation to implant therapy did not improve PSA outcome in high-risk patients but resulted in a PSA outcome that was not statistically different compared with the results obtained using RP or RT in intermediate-risk patients. These results were unchanged when patients were stratified using the traditional rankings of biopsy Gleason scores of 2 through 4 vs 5 through 6 vs 7 vs 8 through 10. Conclusions. - Low-risk patients had estimates of 5-year PSA outcome after treatment with RP, RT, or implant with or without neoadjuvant androgen deprivation that were not statistically different, whereas intermediate- and high-risk patients treated with RP or RT did better then those treated by implant. Prospective randomized trials are needed to verify these findings.