Twenty-Four-Month Postradiation Prostate Biopsies Are Strongly Predictive of 7-Year Disease-free Survival : Results From a Canadian Randomized Trial

• Published in: Cancer 2009-02, Vol.115 (3), p.673-679
• Main Authors: CROOK, Juanita M, MALONE, Shawn, PERRY, Gad, EAPEN, Libni, OWEN, Julie, ROBERTSON, Susan, LUDGATE, Charles, FUNG, Sharon, LOCKWOOD, Gina
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Biopsy; Canada; Disease-Free Survival; Flutamide - therapeutic use; Goserelin - therapeutic use; Humans; Male; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Predictive Value of Tests; Prognosis; Prostatic Neoplasms - pathology; Prostatic Neoplasms - radiotherapy; Radiotherapy Dosage; Treatment Outcome; Tumors; Tumors of the urinary system; Urinary tract. Prostate gland
• ISSN: 0008-543X; 1097-0142
• DOI: 10.1002/cncr.24020

The objective of this study was to evaluate the predictive value of prostate biopsies that were obtained 24 months after the completion of radiotherapy (RT) with respect to disease-free survival (DFS) in a randomized trial that compared 3 months versus 8 months of neoadjuvant hormone therapy before conventional dose external RT. From February 1995 to June 2001, 378 men were randomized to receive either 3 months or 8 months of combined flutamide and goserelin before they received 66 Gray of RT at 4 participating centers. By risk group, 26% of patients were categorized as low risk, 43% were categorized as intermediate risk, and 31% were categorized as high risk. The 2 treatment arms were balanced in terms of age, Gleason score, clinical tumor classification, risk group, and presenting prostate-specific antigen level. The median follow-up for the patients who remained alive was 6.6 years (range, 1.6-10.1 years). Of 361 evaluable patients, 290 patients remained alive. Post-RT prostate biopsies were performed between 24 and 30 months after the completion of RT in 3 of the 4 centers. Biopsies that had residual tumor with severe treatment effect were considered indeterminate, and biopsies that had minimal or no treatment effect were considered positive. The 5-year rate of actuarial freedom from any failure for the 3-month arm versus the 8-month arm was 72% versus 75% (P = .18). The DFS for patients who had negative and indeterminate biopsies was similar. Two-year post-treatment biopsy status was a strong predictor of 5-year DFS rate (82% and 83% for negative and indeterminate biopsies, respectively, vs 27% for positive biopsies; P < .0001). Multivariate analysis indicated that biopsy status (P < .0001) and Gleason score (P < .0001) were the strongest determinates of biochemical DFS. Two-year post-RT prostate biopsies were strongly predictive of subsequent DFS. Biopsies with severe treatment effect were considered negative.