Research: 2018 – Okanagan

Project Title:
High Dose Rate Brachytherapy for Prostate Cancer
Investigators:
Dr. Juanita Crook, BC Cancer Foundation
 
Dr. Crook did her medical training at the University of Toronto, Residency in Radiation Oncology at the Princess Margaret Hospital and is currently a Professor of Radiation Oncology at the University of British Columbia. She is a staff Radiation Oncologist at the Center for the Southern Interior in Kelowna BC where she has developed image-guided HDR gynecologic brachytherapy, US-planned HDR prostate brachytherapy and permanent seed brachytherapy for breast cancer. Previously a Professor of Radiation Oncology at the University of Toronto/University Health Network and Associate Professor at the University of Ottawa, she has particular interest in intermittent androgen suppression, post radiation prostate biopsies and penile brachytherapy. She has written 24 book chapters, over 200 journal articles and is a frequent speaker at international meetings, in English, French and Spanish. She was Scientific Chair of the 2007 American Brachytherapy Society meeting and frequently teaches at the ABS Prostate Brachytherapy School. She is former president of the Board of the American Brachytherapy Society, recipient of the Thom Shanahan Distinguished Brachytherapy Educator Award and the ABS 2017 Henschke Award, the highest honor awarded by the American Brachytherapy Society for contributions to the field of brachytherapy.
Project Abstract:
High Dose Rate (HDR) brachytherapy is the most accurate and precise way of treating prostate cancer with radiation. Because HDR brachytherapy is delivered rapidly, patients recover more quickly and are able to return to normal living sooner. Using advanced imaging, BC Cancer experts are able to determine the exact location of the cancer within the prostate and deliver a higher dose of radiation to the site that needs it most. The HDR brachytherapy program, which began in 2011, has recently expanded to include men with earlier-stage, less aggressive cancers who may not have not been eligible for this treatment until now. We are comparing the current standard—a permanent Low Dose Rate seed implant—to HDR. These men are also eligible for genetic testing to determine the aggressiveness of the cancer and help to predict the response to brachytherapy and/or need for additional treatment.
Scientific Abstract:
The primary focus of our evolving HDR prostate brachytherapy program is to improve tumor targeting, to allow dose escalation where it is needed to potentially improve efficacy while maintaining the same very low level of side effects. We have shown that dose escalation to the dominant lesion in the prostate can be taken to 125-140% of prescription while respecting normal organ dose constraints and homogeneity. This produces a lower and earlier PSA nadir without increasing toxicity. Only HDR brachytherapy permits this precise form of dose painting in radiation delivery for prostate cancer. Identification of the site of tumor within the prostate also allows MR-directed biopsies to be performed under anesthesia, at the start of the brachytherapy procedure. In our brachytherapy monotherapy randomized trial further biopsies will be taken from the HDR patients before their second fraction of HDR brachytherapy to assess the reaction to the first fraction in terms of up-regulation of genes for vascularization, oxygenation, and immunologic response. This may help to provide answers as to the optimal fractionation for HDR brachytherapy and for other forms of hypofractionated radiation.
Impact on prostate cancer patients:
The shorter recovery time from HDR brachytherapy (3 months to return to baseline urinary function scores compared to a median of 6 months after LDR brachytherapy) is being established in our 2 randomized studies, one for boost brachytherapy patients and the other for those receiving brachytherapy as monotherapy. In addition, our biopsy program and our collaboration with the Deeley Research laboratory will help to define dose fractionation for HDR brachytherapy.