A comparison of external beam radiation therapy versus radical prostatectomy for patients with low risk prostate carcinoma diagnosed, staged, and treated at a single institution

BACKGROUND, The authors retrospectively reviewed their institution's long t erm experience treating a group of comparably staged low risk prostate carc inoma patients with either radical prostatectomy or external beam radiation therapy (RT) to determine whether the method of treatment resulted in sign ificant differences in biochemical control and/or survival. METHODS. From January of 1987 through December of 1994, 382 patients (157 w ho underwent radical prostatectomy and 225 who received external beam RT) w ere treated with curative intent for localized prostate carcinoma at Willia m Beaumont Hospital. All patients had a pretreatment serum prostate specifi c antigen (PSA) level less than or equal to 10.0 ng/mL and a biopsy Gleason score less than or equal to 6. Patients treated with RT received a median dose of 66.6 gray (Gy) (range, 59.2-70.2 Gy) to the prostate. Patients trea ted surgically underwent radical retropubic prostatectomy with a pelvic lym ph node dissection. For surgical patients, biochemical failure was defined as a detectable PSA level greater than or equal to 0.2 ng/mL at any time af ter prostatectomy For RT patients, biochemical failure was defined accordin g to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition. Pretreatment PSA levels and Gleason scores were not signi ficantly different between patients treated with radical prostatectomy or R T. The median follow-up in each treatment group was 5.5 years. RESULTS. The 7-year actuarial rates of biochemical control and cause specif ic survival were not significantly different between patients treated eithe r with radical prostatectomy or RT (67% vs. 69% for biochemical control and 99% vs. 97% for cause specific survival, respectively). A number of clinic al, pathologic, and treatment-related factors were analyzed for an associat ion with biochemical failure (i.e., age, pretreatment PSA, Gleason score, a nd treatment modality). Only pretreatment PSA and Gleason score were signif icantly related to outcome in both univariate and multivariate analyses. CONCLUSIONS. Low risk prostate carcinoma patients with similar pretreatment PSA levels and biopsy Gleason scores treated at the same institution with either radical prostatectomy or RT achieved similar 7-year rates of biochem ical control and cause specific survival, regardless of treatment technique . These findings suggest that for patients with pretreatment PSA levels les s than or equal to 10 ng/mL and Gleason scores less than or equal to 6, con ventional doses of external beam RT and radical retropubic prostatectomy ca n be expected to produce comparable treatment results unaffected by age at diagnosis. (C) 2000 American Cancer Society.