New Imaging System Makes Brachytherapy More Accurate
Optimal results after treatment with brachytherapy (implantation of radioactive seeds into the prostate) “have been shown to rely heavily upon the ability of physicians to place the seeds precisely in such a way as to cover the prostate with radiation, while avoiding too much radiation to surrounding organs,” says radiation oncologist Danny Song, M.D. “This way, the cancer is cured and unnecessary side effects are avoided.”
However, he adds, “in the past this level of precision was not always achievable, even by experienced physicians. Due to a variety of factors, implanted seeds sometimes did not end up exactly in their intended positions.” Even with the help of ultrasound, which allows physicians to view the prostate during the procedure, seeds do not always show up on the ultrasound image after placement, and any misplaced seeds might not always be found and corrected in the operating room.
Song, Hopkins colleague Junghoon Lee, Ph.D., and a team of scientists may have found a better way. Supported by funding from the National Cancer Institute and working in collaboration with an Illinois-based company, Acoustic Medsystems, and scientists at Queen’s University in Ontario, Canada, Song and Lee have developed a system that allows precise visualization of seeds during brachytherapy. This system links an x-ray machine, which is capable of viewing the seeds but not the prostate, to an ultrasound, which can view the prostate but not the seeds. “Computer software identifies the seeds on the x-ray and projects their images onto the ultrasound, allowing the physician to see exactly where the seeds are in relation to the prostate,” says Song. “This means that during the procedure, the physician can adjust the placement of seeds based on the actual locations of the seeds that have already been deposited, resulting in an improved seed distribution.” The system has recently received FDA approval. Song and colleagues recently presented this research at the American Brachytherapy Society.
In other news from the Department of Radiation Oncology and Molecular Radiation Sciences:
Very-high-risk localized prostate cancer: There’s high-risk prostate cancer, and then there’s very high-risk prostate cancer. Recently, Hopkins urologists Ashley Ross, M.D., Ph.D., and Edward Schaeffer, M.D, Ph.D. defined a subgroup of “very high-risk” men as having primary Gleason pattern 5 cancer; more than 4 cores with Gleason sum 8–10 cancer; or multiple high-risk factors. In a recent study, radiation oncologists Theodore L. DeWeese, M.D., Phuoc T. Tran, M.D., Ph.D,. and Song collaborated with Brady urologists to look at the outcomes and risk factors of very high-risk men after definitive radiation therapy. The Hopkins Genitourinary Radiation Oncology patient database contained 289 patient who met the very high-risk criteria; these men were followed an average of 14 years after treatment. “Like men treated with surgery, very high-risk men treated with radiation had significantly higher rates of 10-year biochemical failure, metastases and overall survival when compared to men with standard high-risk disease,” says DeWeese. “We believe we can use these characteristics to distinguish very high-risk men to help in counseling them better about treatment and also to help select candidates for clinical trials.” This work was presented at the annual meeting of Radiation Oncologists known as ASTRO.