PREDICTORS OF IMPROVED OUTCOME FOR PATIENTS WITH LOCALIZED PROSTATE-CANCER TREATED WITH NEOADJUVANT ANDROGEN ABLATION THERAPY AND 3-DIMENSIONAL CONFORMAL RADIOTHERAPY

Purpose: To identify prognostic variables that predict for improved bi ochemical and local control outcome in patients with localised prostat ic cancer treated with neoadjuvant androgen deprivation (NAAD) and thr ee-dimensional conformal radiotherapy (3D-CRT). Materials and Methods: Between 1989 and 1995, 213 patients with localized prostate cancer we re treated with a 3-month course of NAAD that consisted of leuprolide acetate and flutamide before 3D-CRT. The purpose of NAAD in these pati ents was to reduce the preradiotherapy target volume so as to decrease the dose delivered to adjacent normal tissues and thereby minimize th e risk of morbidity from high-dose radiotherapy. The median pretreatme nt prostate-specific antigen (PSA) level was 15.3 ng/mL (range, 1 to 5 60 ng/mL). The median 3D-CRT dose was 75.6 Gy (range, 64.8 to 81 Gy), and the median follow-up time was 3 years (range, 1 to 7 years). Resul ts: The significant predictors for improved outcome as identified in a multivariate analysis included pretreatment PSA level less than or eq ual to 10.0 ng/mL(P < .001), NAAD-induced preradiothercrpy PSA nadir l ess than or equal to 0.5 ng/mL (P < .001), and clinical stage less tha n or equal to T2c(P < .04). The 5-year PSA relapse-free survival rates were 93%, 60%, and 40% for patients with pretreatment PSA levels less than or equal to 10 ng/mL, 10 to 20 ng/mL, and greater than 20 ng/mL, respectively (P < .001). Patients with preradiotherapy nadir levels l ess than or equal to 0.5 ng/mL after 3 months of NAAD experienced a 5- year PSA relapse-free survival rate of 74%, as compared with 40% for p atients with higher nadir levels (P < .001). The incidence of a positi ve biopsy among 34 patients pretreated with androgen ablation was 12%, as compared with 39% for 117 patients treated with 3D-CRT alone who u nderwent a biopsy (P < .001). Conclusion: For patients treated with NA AD and high-dose 3D-CRT, pretreatment PSA, preradiotherapy PSA nadir r esponse, and clinical stage are important predictors of biochemical ou tcome. Patients with NAAD-induced PSA nadir levels greater than 0.5 ng /mL before radiotherapy are more likely to develop biochemical failure and may benefit from more aggressive therapies. (C) 1998 by American Society of Clinical Oncology.