Isoray - Innovative Brachytherapy

Isoray’s Cesium-131 Featured in Presentations at American Brachytherapy Society’s Annual Conference

Jun 21, 2022

RICHLAND, WASHINGTON – June 21, 2022 – The growing body of information regarding Isoray, Inc.’s  (NYSE American: ISR) Cesium-131 in treating prostate cancer was highlighted in two presentations at the just concluded American Brachytherapy Society’s annual conference in Denver, Colorado.

During the conference, the Prostate Snap Oral I scientific session included two abstracts that were presented by The Cesium Advisory Group. The group is comprised of five experienced physicians with extensive experience using Cesium-131 monotherapy for permanent prostate brachytherapy who came together to form the advisory group.

Commenting on the presentations, Isoray CEO Lori Woods said, “Long-term outcomes have demonstrated the significance of Cesium-131 brachytherapy for prostate cancer treatment. These abstracts present valuable information for clinicians on achieving the best possible implant based on the recommendations of experienced Cesium-131 users. They leverage a substantial experience base built over some 15 years for the benefit of current and future prostate brachytherapists. As innovators in brachytherapy, we continue to be proud of our leading brachytherapy treatment that is at the forefront in bringing important benefits to cancer patients and the medical professionals who care for them.”

One of the presentations was entitled, Permanent LDR brachytherapy using Cesium-131 Monotherapy: Updated Recommendations from the Cesium Advisory Group, by authors Brian J. Moran, MD, Bradley Prestidge, MD, MS, Steven Kurtzman, MD, David T. Marshall, MD, MS, Bernard W. Taylor Jr., MD,  and Roksana Tech, MD.

The authors noted that Cesium-131 has a higher photon energy as well as a shorter half-life in comparison to its counterparts, Iodine-125 and Palladium-103. They stated that the optimal Cesium-131 implant will deliver a safe and effective dose with the minimum possible toxicity. A review of implant techniques examining variability and/or similarity of different sized prostates for each brachytherapist was undertaken. The data acquired was compared to the past Cesium Advisory Group’s 2008 recommendations.

The advisory group recommended “homogenous” implants capable of delivering a cancer-killing dose to the prostate gland with as few hot and cold spots as possible. Hot spots deliver more radiation than is necessary, while cold spots may undertreat cancer in the gland. Very homogenous implants are possible with Cesium-131 due to the greater energy of Cesium-131 as compared to some other isotopes. By delivering a dose with Cesium-131 that lacks hot and cold spots and that spares the bladder and rectum, an effective radiation dose may possibly be administered with minimal side effects experienced by the patient. Compared to the 2008 recommendations, they found that the amount of the urethra that receives 30% of the prescription dose (uD30) continues to be less than 140% and the amount of the entire prostate receiving 150% of the prescription dose (pV150) has decreased from <45% to ~20-40%.

The Cesium Advisory Group’s second presentation was entitled, Technique and Preferences for Permanent LDR Prostate Brachytherapy Using Cesium-131. The purpose of their study was to identify individual technique preferences for Cesium-131 prostate implantation and determine if there is a uniform method among the brachytherapists.

While Cesium-131 implants vary on several specifics with regards to technique, the brachytherapists on the panel are uniform in their practice to implant the majority of the Cesium-131 isotope in the periphery. This so-called “peripheral loading” takes dose away from the urethra where it might cause unwanted urinary symptoms. No matter how the Cesium-131 implant is planned and administered, homogeneity and sparing of the nearby sensitive anatomy is recommended and achievable.

The members of the Cesium Advisory Group (CAG) who compiled these reports have performed over 6,000 implants as a group over the years since the introduction of Cesium-131 as a treatment for prostate cancer.

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


Media and Public Relations: Sharon Schultz (302) 539-3747
Investor Relations: Mark Levin (501) 255-1910

About Isoray

Isoray, Inc. is a medical technology company pioneering advanced treatment applications and devices to deliver targeted internal radiation treatments for cancers throughout the body. Isoray, Inc., through its subsidiary, Isoray Medical, Inc., is the sole producer of Cesium-131 brachytherapy seeds. Learn more about this innovative Richland, Washington company and explore the many benefits and uses of Cesium-131 by visiting Follow us on LinkedIn and Twitter.

Safe Harbor Statement

Statements in this news release about Isoray’s future expectations, including whether the studies discussed in this news release will have favorable outcomes in commercial settings, the advantages of Cesium-131 and its delivery systems coupled with surgery, the perception by patients of quality of life outcomes compared to other treatment options, whether demand for and use of Cesium-131 will increase or continue as anticipated and all other statements in this release, other than historical facts, are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (“PSLRA”). This statement is included for the express purpose of availing Isoray, Inc. of the protections of the safe harbor provisions of the PSLRA. It is important to note that actual results and ultimate corporate actions could differ materially from those in such forward-looking statements based on such factors as whether additional studies are released that support the conclusions of the studies discussed in this news release, whether ongoing patient results are favorable and in line with the conclusions of clinical studies and initial patient results, physician acceptance, training and use of our products, whether we, our distributors and our customers will successfully obtain and maintain all required regulatory approvals and licenses to market, sell and use our products in its various forms, changes in laws and regulations applicable to our products, and other risks detailed from time to time in Isoray’s reports filed with the U.S. Securities Exchange Commission. Unless required to do so by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.