Urinary Morbidity Following Cs-131 Brachytherapy for Localized Prostate Cancer

Abstract

Cesium-131 (Cs-131) has recently become available for the treatment of early stage prostate cancer using permanent interstitial prostate brachytherapy. This report describes post-treament urinary morbidity as estimated by repeat International Prostate Symptom Score (IPSS) surveys following Cs-131 monotherapy. Between 11/2004 and 4/2007, 171 consecutive patients underwent Cs-131 brachytherapy by a single physician at a single out-patient center. A prospective data collection effort was undertaken, including the collection of sequential IPSS and IIEF scores and RTOG toxicity surveys at fixed intervals following treatment. A sub-set of 127 patients for whom baseline IPSS and more than one post-treatment IPSS were available was utilized. For this report, summary data were compiled and plotted for all IPSS scores tabulated. The acute retention rate requiring catheterization in this sub-set was 2.4% (3/127). A total of 404 post-treatment IPSS scores were available for analysis. Mean IPSS scores and 95% confidence intervals are plotted in Figure 1. The mean group scores peaked at two weeks to one month, and largely resolved to baseline by four months. Baseline IPSS was the only significant predictor of peak (one month) post-treatment IPSS (by General Linear Model SPSS, Inc., p < 0.0005). Published reports detailing IPSS scores following Iodine-125 brachytherapy suggest that recovery of population baseline IPSS occurs at approximately one year. Based on this data, the resolution of urinary symptoms as measured by group IPSS scores may occur more rapidly with Cs-131. The peak mean IPSS observed was similar to that reported in the published Iodine-125 series. This topic is the subject of an ongoing prospective, randomized protocol at our facility.