The first multi-institutional study to assess a new form of radiation treatment for prostate cancer along with sophisticated real-time tumor tracking is being conducted by Michigan Principal Investigator Daniel A. Hamstra, Ph.D., M.D., assistant professor of the Department of Radiation Oncology and 10 co-researchers at the University of Michigan Health System in Ann Arbor.
The safety of shortened (hypfractionated) stereotactic body radiation therapy (SBRT) is being evaluated with Calypso Medical’s GPS for the body technology, which is employed during prostate radiotherapy for real-time tracking of cancerous tumors. The results thus obtained will be compared with those obtained from conventional radiation treatment.
During radiation treatment, SBRT allows for accurate, precise, and real-time tracking of prostate motion, say Dr. Hamstra and his co-investigators. The administration of large, concentrated radiation doses is a matter of concern because the surrounding healthy tissue is also subjected to the same high doses resulting in potential for side effects, such as rectal injury, impotence and difficulty urinating.
The prostate can be accurately located using the Calypso Medical’s real-time tracking technology allowing doctors to be more confident about administering larger SRBT doses and decreasing the entire amount of treatments.
Prof. Hamstra states: “To a large extent, identification of prostate location has only been performed prior to the start of treatment without taking into account the motion of the prostate during treatment, yet precise targeting of the prostate gland during radiation is critically important in order to avoid delivering unintended radiation to healthy tissue.
This is the first multi-institutional study to incorporate use of the Calypso real-time tumor tracking technology, which allows us to significantly reduce the margin of healthy tissue around the prostate to prevent the development of unwelcome side effects. We are optimistic that use of the Calypso System in concert with a small number of dose-intensified treatment sessions may be a way to optimize SBRT.”
The multi-site study is aimed at evaluating the safety and efficacy of a short-term treatment plan with continuous real-time prostate motion evaluation as compared with conventional treatment in patients.
Over a period of 39 months, the Phase II study will be conducted in 66 patients wherein each patient will be subjected to five treatment sessions (fractions) of 30-minute each with a resting interval of at least two days between each fraction. A total dosage of 37 Gray (unit of absorbed radiation dose) will be administered with each fraction size comprising 7.4 Gray. Compared to a conventional treatment of 40-45 daily sessions spread over 8 to 9 weeks, the five-fraction treatment period is expected to last between 15-19 calendar days.