Prostate brachytherapy: a descriptive analysis from CaPSURE

Abstract

Purpose: The purpose of this study was to describe demographic and clinical characteristics in a large disease registry of prostate cancer patients treated with prostate brachytherapy (PB) and to identify factors influencing the use of supplemental external beam (SEB) radiation therapy and choice of isotope.

Methods and materials: Data were abstracted from the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), a disease registry of 11,804 men with various stages of prostate cancer. The study population consisted of those men who were diagnosed with prostate cancer between 1990 and 2003, had no prior history of cancer and were treated with PB (alone or with SEB). The influence of patient demographics, disease characteristics, and year of diagnosis on the use of SEB and isotope choice was examined.

Results: The study population included 791 men. Six hundred nine men (77%) were treated with PB alone and 182 men (23%) were treated with PB and SEB. Patient demographics were not associated with the use of SEB. Disease characteristics were associated with the use of SEB. Patients treated with PB and SEB had higher pretreatment prostate-specific antigen (PSA), higher T-stage, higher Gleason score, and were more likely to be placed in the high-risk category (all p<0.01). The use of SEB increased over the period studied. In a multivariate analysis, patients diagnosed after 1999 were much more likely to receive SEB after controlling for disease characteristics (PSA, T-stage, Gleason). Likewise, higher clinical PSA (odds ratio [OR]=1.08; 95% confidence interval [CI]: 1.04-1.13), higher biopsy Gleason (OR=3.64; 95% CI: 2.60-5.09), and cT2 vs. cT1 (OR=2.06; 95% CI: 1.22-3.48) were more likely to have PB with SEB than PB alone. Patient demographics differed according to isotope. Compared to men treated with 125)I, men treated with (103)Pd were older, less educated, less wealthy, and less likely to have private insurance. Disease characteristics also differed according to isotope. Compared to men treated with 125I, men treated with 103Pd had higher T-stages, higher Gleason scores, and were more likely to be placed in the intermediate- or high-risk category. The choice of isotope did not change over time.

Conclusions: The use of SEB is associated with disease characteristics. SEB has increased over the period studied. Isotope choice is associated with patient demographics and disease characteristics.