Journal of Clinical Oncology, Vol 16, 3380-3385, Copyright © 1998 by American Society of Clinical Oncology
Predictors of improved outcome for patients with localized prostate cancer treated with neoadjuvant androgen ablation therapy and three- dimensional conformal radiotherapy
MJ Zelefsky, O Lyass, Z Fuks, T Wolfe, C Burman, CC Ling and SA Leibel
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021-6007, USA. zelefskm@mskcc.org
PURPOSE: To identify prognostic variables that predict for improved
biochemical and local control outcome in patients with localized prostatic
cancer treated with neoadjuvant androgen deprivation (NAAD) and
three-dimensional conformal radiotherapy (3D-CRT). MATERIALS AND METHODS:
Between 1989 and 1995, 213 patients with localized prostate cancer were
treated with a 3-month course of NAAD that consisted of leuprolide acetate
and flutamide before 3D-CRT. The purpose of NAAD in these patients was to
reduce the preradiotherapy target volume so as to decrease the dose
delivered to adjacent normal tissues and thereby minimize the risk of
morbidity from high-dose radiotherapy. The median pretreatment
prostate-specific antigen (PSA) level was 15.3 ng/mL (range, 1 to 560
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). RESULTS: The
significant predictors for improved outcome as identified in a multivariate
analysis included pretreatment PSA level < or = 10.0 ng/mL(P < .00),
NAAD-induced preradiotherapy PSA nadir < or = 0.5 ng/mL (P < .001),
and clinical stage < or = T2c (P < .04). The 5- year PSA relapse-free
survival rates were 93%, 60%, and 40% for patients with pretreatment PSA
levels < or = 10 ng/mL, 10 to 20 ng/mL, and greater than 20 ng/mL,
respectively (P < .001). Patients with preradiotherapy nadir levels <
or = 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 patients with higher nadir
levels (P < .001). The incidence of a positive biopsy among 34 patients
pretreated with androgen ablation was 12%, as compared with 39% for 117
patients treated with 3D-CRT alone who underwent a biopsy (P < .001).
CONCLUSION: For patients treated with NAAD and high-dose 3D-CRT,
pretreatment PSA, preradiotherapy PSA nadir response, and clinical stage
are important predictors of biochemical outcome. 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.