Utilization and expense of adjuvant cancer therapies following radical prostatectomy

We sought to identify the costs of adjuvant therapies following radical prostatectomy (RP) and factors associated with their receipt.

We used SEER-Medicare data from 2004-2006 to identify 4247 men who underwent RP, of whom 600 subsequently received adjuvant therapies. We used Cox regression to identify factors associated with receipt of adjuvant therapies. Health care expenditures within 12 months of diagnosis were compared for RP alone versus RP with adjuvant therapies.

Biopsy Gleason score, prostate-specific antigen, risk group, and SEER region were significantly associated with receipt of adjuvant treatments (all P<.001). Higher surgeon volume was associated with lower odds of receiving adjuvant therapies (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.78 [P<.001]). Factors associated with increased receipt of adjuvant therapies were positive surgical margins (HR, 3.02; 95% CI, 2.55-3.57 [P<.001]), high-risk group versus low-risk group (HR, 7.65; 95% CI, 5.64-10.37 [P<.001]), lymph node-positive disease (HR, 5.36; 95% CI, 3.71-7.75 [P<.001]), and treatment in Iowa (HR, 1.93; 95% CI, 1.12-3.32 [P = .019]) and New Mexico/Georgia/Hawaii (HR, 1.92; 95% CI, 1.09-3.39 [P = .025]) versus San Francisco SEER regions (baseline). Age, race, comorbidities, and surgical approach were not associated with use of adjuvant therapies. The median expenditures attributable to postprostatectomy hormonal therapy, radiation therapy, and radiation with hormonal therapy versus were $1361, $12,040, and $23,487.

Men treated by high-volume surgeons were less likely to receive adjuvant therapies. Regional variation and high-risk disease characteristics were associated with increased receipt of adjuvant therapies, which increased health care expenditures by 2- to 3-fold when radiotherapy was administered.