Purpose: Long-term outcomes reveal equivalent biochemical outcomes with low-dose-rate (LDR) brachytherapy (BT) compared with radical prostatectomy and external-beam radiotherapy for the management of prostate cancer. Iodine-125, the most commonly used isotope, may be associated with long-term urinary consequences. Cesium-131 (131Cs) has a higher dose rate and shorter dose delivery time, predicting a shorter duration of urinary morbidity. We report our institution's high-volume experience and the most mature data to date on outcomes with 131Cs prostate BT.
Methods and materials: 571 men (median age: 65.38 years) with low (55%)-, intermediate (36%)-, and high-risk disease (9%) received monobrachytherapy, dual-modality, or trimodality using 131Cs at a single institution. Risk groups were defined according to the National Comprehensive Cancer Network definition. Median prescription dose for definitive LDR-BT and LDR-BT boost was 115 Gy and 70 Gy, respectively. Median initial PSA was 6.1 ng/mL (IQR: 4.6-8.7).
Results: Median followup time was 5 years. 5/7-year overall survival for low-, intermediate-, and high-risk patients was 96.9%/96/9%, 92.8%/89.7%, and 95.8%/87.1%, respectively (p = 0.02). 5/7-year freedom from biochemical failure for low-, intermediate-, and high-risk patients was 98.5%/96.3%, 94.1%/86.4%, and 93.2%/74.5%, respectively (p < 0.01). 5/7-year prostate cancer -specific survival was 100%/100%, 99.3%/99.3%, and 98.0%/98.0% for low-, intermediate-, and high-risk patients, respectively (p < 0.01).
Conclusions: 131Cs is a viable alternative isotope for prostate brachytherapy for organ-confined disease. Long-term biochemical control and survival outcomes are excellent and on par with those attained with the use of 125I or 103Pd. This report therefore supports the continued use of 131Cs as an effective and comparable alternative isotope.
Keywords: Biochemical; Brachytherapy; Cesium; Low dose rate; Outcomes; Prostate.
Published by Elsevier Inc.