AN ANALYSIS OF CLINICAL AND TREATMENT RELATED PROGNOSTIC FACTORS ON OUTCOME USING BIOCHEMICAL CONTROL AS AN END-POINT IN PATIENTS WITH PROSTATE-CANCER TREATED WITH EXTERNAL-BEAM IRRADIATION

Purpose: We reviewed our institution's experience in treating patients with clinically localized prostate cancer with external beam irradiat ion (RT) to determine if previously analyzed clinical and treatment re lated prognostic factors affected outcome when biochemical control was used as an end-point to evaluate results. Materials and methods: Betw een 1 January 1987 and 31 December 1991, 470 patients with clinically localized prostate cancer were treated with external beam RT using loc alized prostate fields at William Beaumont Hospital. Biochemical contr ol was defined as PSA nadir less than or equal to 1.5 ng/ml within 1 y ear of treatment. After achieving nadir, if two consecutive increases of PSA were noted, the patient was scored a failure at the time of the first increase. Prognostic factors, including the total number of day s in treatment, the method of diagnosis, a history of any pretreatment transurethral resection of the prostate (TURF) and the type of boost were analyzed. Results: Median follow-up was 48 months. No statistical ly significant difference in rates of biochemical control were noted f or treatment time, overall time (date of biopsy to completion of RT), history of any pretreatment TURP, history of diagnosis by TURF, or boo st techniques. patients diagnosed by TURF had a significant improvemen t in the overall rate of biochemical control (P < 0.03) compared to tr ansrectal/transperineal biopsy. The 5-year actuarial rates were 58 ver sus 39%, respectively. This improvement was not evident when pretreatm ent PSA, T stage, or Gleason score were controlled for. On multivariat e analysis, no variable was associated with outcome. When analysis was limited to a more favorable group of patients (T1/T2 tumors, pretreat ment PSA less than or equal to 20 ng/ml and Gleason score <7), none of these variables were significantly predictive of biochemical control when controlling for pretreatment PSA, T stage and Gleason score. Conc lusions: No significant effect of treatment time, overall time, pretre atment TURF, or boost technique was noted on outcome in patients treat ed with conventional external beam irradiation when biochemical contro l was used as the end-point to evaluate results. (C) 1997 Elsevier Sci ence ireland Ltd.