Noted medical researchers from around the country gathered at the 26th annual American Association of Physicists in Medicine (AAPM) conference in Minneapolis, MN, July 22-26, to present results from their studies focusing on Proxcelan with Cesium-131. The presenters illustrated the radiobiological characteristics and related dosimetric outcomes in treatment planning using Proxcelan with Cesium-131 - the newest isotope used in brachytherapy for the treatment of prostate cancer and the first breakthrough in more than 20 years.
These studies have added to the growing body of scientific research building for Proxcelan with Cesium-131, a proprietary product of IsoRay Medical.
"Innovations are important to the future of medical care, and I believe that Proxcelan with Cesium-131 represents one of the biggest advancements to come along in many years for prostate brachytherapy," said Dr Bradley R Prestidge, President/CEO/Medical Director of the Texas Cancer Clinic in San Antonio, Texas.
A multi-institutional trial, with Prestidge as principal investigator, concluded earlier this year that low-dose (LDR) brachytherapy treatment using Cesium-131 for prostate cancer "...has come into widespread use; and the clinical results of this trial are mature enough to be of immediate, important, practical use to practitioners."
"Several of the papers presented at AAPM confirm earlier results regarding Cesium-131's excellent dosimetric properties and applicability for prostate cancer," said Dr IsoRay Medical Director Steven Kurtzman, Director of Brachytherapy for Western Radiation Oncology in San Mateo, CA.
Proxcelan with Cesium-131 offers patients unique advantages over other medical isotopes. Increasingly, prostate cancer patients and their doctors who decide on seed brachytherapy choose Cesium-131 treatment because of its significant advantages over palladium-103 and iodine-125, two other isotopes currently in use. These advantages include:
Higher energy
Proxcelan with Cesium-131 has a higher average energy than any other commonly used prostate brachytherapy isotope on the market. Energy is a key factor in how uniformly the radiation dose can be delivered throughout the prostate. Early studies demonstrate proxcelan with Cesium-131 implants are able to deliver the required dose while maintaining good homogeneity across the gland itself and potentially reducing unnecessary dose to critical structures such as the urethra and rectum.
Shorter half-life
Cesium-131 has the shortest half-life of any prostate brachytherapy isotope at 9.7 days. Cesium-131 delivers 90% of the prescribed dose to the prostate in just 33 days compared to 58 days for palladium-103 and 204 days for iodine-125. The short half-life of Cesium-131 reduces the duration of time during which the prostate receives the irritating effects of the radiation. Early studies demonstrate Cesium-131 is well tolerated with minimal to moderate urinary symptoms that resolve relatively rapidly, within approximately 4-8 weeks.
Higher biologically effective dose
Another benefit to the short half-life of proxcelan with Cesium-131 is what is known as the 'biological effective dose' or BED. BED is a way for healthcare providers to predict how an isotope will perform against slow- versus fast-growing tumours. Studies have shown Cesium-131 is able to deliver a higher BED across a wide range of tumour types than either Iodine-125 or Palladium-103. Although prostate cancer is typically viewed as a slow-growing cancer, it can present with aggressive features. Cesium-131's higher BED may be particularly beneficial in such situations.
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