The influence of percentage of preradiation needle biopsies with adenocarcinoma and total radiation dose on the pathologic response of unfavorable prostate adenocarcinoma.

We studied relationships among clinicopathologic factors in 78 patients with unfavorable prostate adenocarcinoma treated in a dose-escalation radiation therapy (RT) study using pre- and 18-month protocol post-RT biopsy specimens. Pre-RT factors analyzed were serum prostate-specific antigen (PSA) level, Gleason score, and percentage of needle cores with adenocarcinoma; post-RT factors were percentage of needle cores with adenocarcinoma and amount of radiation effect on the adenocarcinoma. Of 78 patients, 42 (54%) had residual adenocarcinoma in the post-RT biopsy specimen. Lower total RT dose and dose per implant and greater serum PSA level were associated with an increasing percentage of needle cores with residual post-RT adenocarcinoma. Lower RT dose, an increasing percentage of pre-RT needle cores with adenocarcinoma, and a greater serum PSA level were associated with an increasing percentage of post-RT needle cores with no to moderate RT effect scores in adenocarcinoma. The mean percentage of pre-RT and post-RT needle cores with adenocarcinoma was greater in patients with post-RT biopsy specimens with no to moderate RT effect. The percentage of pre-RT needle cores with adenocarcinoma (a surrogate marker of adenocarcinoma volume), serum PSA level, and RT dose are the key components in the dose-response relationship. Gleason score and gland volume did not contribute significantly to this relationship.