Grant: Travel Awards - Institute Community Support

In Canada, an estimated 196,900 people will be diagnosed with cancer in 2015 and 78,000 cancer-related deaths will occur. 26% of the cases will be breast cancer, making it the leading diagnosed cancer and second leading cause of cancer-related deaths in Canadian women. Radiation therapy is an effective treatment for multiple types of localized primary tumours and a keystone treatment following breast-conserving surgery. Ideally, X-ray treatment after surgery will destroy any remaining cancer cells. However some patients redevelop a tumour mass after treatment, suggesting that some tumour cells can survive radiation therapy. These surviving cells may cause local reoccurrence or migrate to other locations in the body (metastasis). Metastasis is responsible for most breast cancer related mortalities. My research is focused on the tumour cells that survive radiation therapy and to test whether radiation increases metastasis of these cells. I have found that breast cancer cells that survive low doses of radiation treatment, similar to what is used in the clinic, can migrate faster and further from their site of origin as compared to untreated cells. These surviving cells also possess an enhanced invasive ability and are able to breakdown surrounding structures that confine them, allowing for further dissemination compared to untreated cells. Proteins produced by irradiated tumour cells are able to cause other tumour cells to migrate. Systemic chemotherapy or novel inhibitors of tumour cell invasion/migration are viable options to prevent potentially metastatic tumour cells from leaving the primary tumour during radiotherapy. Findings from our research may potentially reveal new methods to determine patients who may be at risk of recurrence after radiotherapy. Our findings will help alert clinicians to the potential risk of using radiation treatment alone to treat cancer patients and to consider combination therapies to reduce or eliminate the possibility of metastasis.