Grant: Project Grant

Prostate and breast cancer are the most common cancers for Canadians, at 20.7% and 25.5% of men's and women's cancers, respectively. Radiation therapy (RT) is a preferred treatment modality, either alone or combined, for 50% of cancer patients. In recent years, technological developments have enabled RT to accomplish significant advances in the local control of various cancer sites; 40% of cancers are cured by RT, compared to 49% by surgery and 11% by chemotherapy (2010 IAEA report). As such, RT remains a formidable, and very affordable, weapon in the fight against cancer. One RT approach is low-dose-rate brachytherapy that using permanently implanted mm-size sources. These radioactive sources are implanted directly in the tumour, enabling higher local dose and greater protection to organs-at-risk. These procedures are usually performed as a 1-day outpatient procedures. It provides a well-tolerated treatment with a good therapeutic ratio. Accurate knowledge of dose-outcome relationships is critical to success in radiation therapy. Despite the overall good results clinically, a critical barrier to progress in further advancing brachytherapy treatments is the inaccuracy of dose evaluations which lead to a major disconnect between clinically-measured outcomes and "accurate" dose distributions. The assembled team comprised of world-experts in state-of-the-art dose calculations as well as world-leading brachytherapy physicians from all major programs across Canada comes together to tackle this problem. The proposed research will provide more accurate knowledge of prescription doses needed for relapse-free survival as well as a better understanding of radiation toxicity thresholds. It has the potential to further improve tumour control while reducing the incidence and severity of complications, thus enhancing patient quality of life and reducing healthcare costs: simply put improving the therapeutic ratio of BT treatments of prostate and breast cancer.