Open Access

ARTICLE

Cesium 131 versus iodine 125 implants for prostate cancer: evaluation of early PSA response

Jeffrey J. Tomaszewski, Marc C. Smaldone, Sami Makaroun, Ryan P. Smith, Sushil Beriwal, Ronald M. Benoit

Departments of Urology and Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
Address correspondence to Dr. Jeffrey J. Tomaszewski, Department of Urology, Kaufman Building, Suite 700, 3471 Fifth Avenue, Pittsburgh, PA, 15213 USA

Canadian Journal of Urology 2010, 17(5), 5360-5364.

Abstract

Introduction: Given the shorter half-life of cesium-131 (Cs-131) compared to iodine-125 (I-125), we hypothesized that initial PSA outcomes may differ. We compare initial PSA outcomes in men undergoing Cs-131 prostate brachytherapy to men treated with I-125.
Patients and methods: The first post-treatment PSA (obtained 3-6 months after the procedure) was compared in patients undergoing I-125 prostate brachytherapy to that of patients undergoing Cs-131 prostate brachytherapy at the same institution. Comparisons included the total cohort as well as low and intermediate risk patients.
Results: Mean pre-treatment PSA was 6.9 ng/mL in the I-125 cohort, and 6.9 ng/mL in the Cs-131 cohort. Mean initial post-treatment PSA was 0.9 ng/mL (range < 0.1-4.6) in the I-125 cohort and 1.2 ng/mL (range < 0.1-23.5) in the Cs-131 patients. For low risk patients, mean pre-treatment PSA was 5.8 ng/mL in the I-125 cohort, and 5.1 ng/mL in the Cs-131 cohort. Initial mean post-treatment PSA for low risk patients was 1.2 ng/mL (range < 0.1-4.6) in the I-125 group and 1.0 ng/mL (range < 0.1-2.9) in the Cs-131 patients (p = 0.37). For intermediate risk patients, mean pre-treatment PSA was 7.3 ng/mL in the I-125 cohort, and 7.3 ng/mL in the Cs-131 cohort. Mean initial post-treatment PSA in intermediate risk patients was 1.5 ng/mL (range < 0.1-2.9) in the I-125 group and 1.2 ng/mL (range < 0.1-4.6) in the Cs-131 patients (p = 0.52).
Conclusions: Given the shorter half-life of Cs-131 compared to I-125, we hypothesized that initial post-brachytherapy PSA levels were similar between men receiving treatment with Cs-131 and I-125. The aim of the present study is not to predict long term outcome after Cs-131 prostate brachytherapy, but rather to simply compare initial PSA outcomes in men undergoing prostate brachytherapy with I-125 to Cs-131. Long term data are needed to document cancer control achieved with Cs-131.

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