Dr. Michael Zelefsky, a radiation oncologist, is Professor of Radiation Oncology, Chief of the Brachytherapy Service, and Co-Leader of the Genitourinary Disease Management Team at Memorial Sloan Kettering Cancer Center in New York City.
Prostatepedia recently spoke with him about how advances in imaging have impacted radiation therapy. Subscribe to read the entire conversation.
Do you think molecular imaging will be incorporated soon?
Dr. Zelefsky: There’s a lot of excitement with PET/CT imaging. PET imaging fused with MRI is also emerging now. This has been used effectively for various disease sites, not only prostate cancer. For prostate cancers specifically, newer PET tracers such as PET C-11 Choline and exciting developments in PSMA tracers will be used. These provide us unique opportunities to see where micrometastatic disease could be lodged. That information is critical for the radiation oncologist to pinpoint the disease. There are also exciting developments using some of these tracers as a form of therapy. Tracers such as PSMA are linked to lutetium-177 and tracers can be integrated with radiation planning as well. We are on the verge of seeing these new developments; these changes will soon be integrated with radiation.
Is there anything else you think patients should know about imaging’s role in radiation therapy?
Dr. Zelefsky: With new advances in imaging and by working in close collaboration with diagnostic radiology, we are getting much more accurate information concerning where microscopic disease is located and the critical zones within the prostate where tumors are lodged. We use imaging to consider re-biopsying patients where there may be a discrepancy between what looks like earlier states of disease, but the MRI shows there is greater volume of disease than what was anticipated. We need to know this information in order to plan the radiation well. We need to consider opportunities to intensify the dose to the DIL in the prostate and whether there is nodal disease and where exactly the nodal disease could be within the pelvis. Imaging plays a huge role in our follow-up with patients, allowing us to detect recurrences earlier than ever before. This is vital information for patients because earlier detection of recurrences allow for salvage therapies much sooner and treating such patients at earlier time points is often associated with more successful outcomes.
In the future, imaging will help us consider focal ablative therapies where the paradigm is shifting in earlier cancer s. Simply put, we could just focus on the DIL and spare the rest of the prostate if we can be sure that there is no significant disease in other parts of the gland. There have been a number of efforts to use focal therapy with advanced imaging to small subunits of the prostate. So new imaging possibilities are opening up new directions and opportunities in the treatment of prostate cancer.