Study Finds Excellent Outcomes for Intermediate Risk Prostate Cancer Patients Treated with Isoray’s Cesium-131

Investigators from the University of Pittsburgh
School of Medicine have published a clinical study that demonstrates excellent outcomes for localized intermediate-risk prostate cancer patients treated with Isoray’s Cesium-131 brachytherapy, commercially known as Cesium Blu.

The published article on the study, Treatment of intermediate-risk prostate cancer with Cs-131: Long-term results from a single institution, was authored by Joshua L. Rodríguez-López, MD, Ankur K. Patel, MD, Ronald M. Benoit, MD, Sushil Beriwal, MD, Ryan P. Smith, MD, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. The peer reviewed paper was published in the January-February 2022 issue of BRACHYTHERAPY, an international multidisciplinary journal of the American Brachytherapy Society. The study analyzed the outcomes for 335 intermediate-risk prostate cancer patients treated with Cesium-131 brachytherapy.

Study patients had significant follow-up time. The median follow-up was 5.8 years, with a range of 4 to 8.9 years. The study found both the “favorable” (147 patients) and “unfavorable” (188 patients) intermediate-risk groups demonstrated excellent biochemical outcomes. Those outcomes were 97.6% and 91.4% respectively at five years. For 135 “favorable” patients treated with Cesium-131 implant alone (excluding 12 patients who were treated with external beam radiation therapy and Cesium-131 implant), the outcome was 98.1%.

Intermediate-risk prostate cancer can be classified as “favorable” (FIR) or “unfavorable” (UIR). In localized prostate cancer, risk increases as PSA (prostate-specific antigen), tumor grade, and tumor stage advance, creating higher risk of treatment failure.

Study author Dr. Ryan P. Smith, MD, said, “The biggest thing we wanted to accomplish in analyzing this data was to try to individualize treatment because the intermediate risk group is the most heterogenous. We used Cesium-131 to decrease the duration of acute toxicity as compared to other radio isotopes because of its shorter half-life. For favorable patients, it is very clear that all you need is Cesium-131 prostate brachytherapy. For unfavorable patients, the combination of external beam radiation followed by Cesium-131 prostate brachytherapy allows us to avoid hormonal therapy for most patients.”

The study adds convincing data to the more than 14 years of accumulated experience with Cesium-131 prostate brachytherapy treatment and builds on the body of literature to support the use of this isotope.

Commenting on the study, Isoray CEO Lori Woods said, “We are very excited by the results of this study. We believe the import of these findings is significant. We further believe this study provides compelling evidence that strongly suggests patients diagnosed with intermediate-risk prostate cancer should be presented with Cesium-131 as a valuable treatment opportunity by clinicians.”

Isoray is a medical technology company and innovator in seed brachytherapy. The Company is the world’s only producer of Cesium-131 brachytherapy, which is powering expanding internal radiation treatment options throughout the body for prostate cancer as well as difficult to treat head and neck, brain, lung, gynecologic, pelvic, and colorectal cancers.

About Isoray
Isoray, Inc., through its subsidiary, Isoray Medical, Inc. is the sole producer of Cesium-131 brachytherapy seeds, commercially known as Cesium Blu, which are expanding brachytherapy options throughout the body.