Predictors of the use of supplemental androgen suppression therapy and external beam radiation in men with high-risk prostate cancer undergoing brachytherapy in community practice.

Purpose: We assessed clinical- and practice-related variables associated with the use of trimodality treatment (androgen suppression therapy, external beam radiation therapy, and brachytherapy) in a community-based cohort of men with high-risk prostate cancer.

Methods And Materials: The study cohort was composed of 1342 men with a prostate-specific antigen level >20ng/mL, clinical tumor stage T3 or T4, and/or Gleason score 8-10 disease at two community radiation facilities, Chicago Prostate Cancer Center (Chicago PCC) and 21st Century Oncology (21C). Logistic regression multivariable analysis was performed to identify factors associated with trimodality treatment.

Results: Of 1342 men treated from 1991 to 2005, 650 (48%) received trimodality therapy. Factors associated with trimodality use include younger age (adjusted odds ratio [AOR] 0.95, p<0.0001), increasing prostate-specific antigen (AOR 1.54, p<0.0001), Gleason score 7 (AOR 2.88, p<0.0001), Gleason score 8-10 (AOR 4.28, p<0.0001), clinical category T2 (AOR 1.40, p=0.012), clinical category T3 (AOR 4.84, p<0.0001), and year of brachytherapy (AOR 1.13, p<0.0001). Patients treated at 21C were 4.6 times more likely to receive trimodality therapy (p<0.0001) than Chicago PCC. There was a significant interaction between cardiovascular comorbidity status and site (comorbidity×21C, AOR 1.74, p=0.025), indicating that less healthy patients were more likely to receive trimodality treatment at 21C than healthy patients and vice versa at Chicago PCC.

Conclusions: Younger men and those with more aggressive pretreatment clinical factors were more likely to receive trimodality treatment in this community cohort of men with high-risk prostate cancer. Selection for trimodality use varied significantly by site indicating a need for treatment standardization in the community.