One of the most promising advances in cancer treatment is the use of biological markers or biomarkers to identify the therapies a particular cancer may or may not respond to. A new study undertaken by the Canadian Cancer Trials Group (CCTG) will look at whether additional radiation therapy is beneficial for patients with a specific subtype of breast cancer called luminal A.
“Studies have shown that radiotherapy to the chest wall and lymph-nodes following mastectomy, and radiotherapy to regional nodes after breast-conserving surgery, reduces the risk of recurrence and breast cancer mortality in women with node-positive breast cancer,” explained Dr Wendy R. Parulekar, Senior Investigator at CCTG.
While these benefits are important, there is a large group of breast cancer patients who will likely not see cancer come back and therefore would not benefit from regional radiotherapy. Biomarkers are increasingly used to identify breast cancers that are likely to recur, or not respond to treatment. It is understood that the luminal A breast cancer subtype has a low risk of recurrence and is less likely to respond to chemotherapy and radiotherapy. This suggests that regional radiotherapy may not be necessary for these patients.
To answer this question, the MA.39 international multicentre randomized trial is underway to determine if regional radiotherapy could be safely omitted in women with 1 to 3 positive axillary lymph- nodes and luminal A breast cancer subtype.
The Principal Investigator of this clinical trial is Dr Tim Whelan, a radiation oncologist at the McMaster University Faculty of Health Sciences in Hamilton, Ontario. The rationale for the trial is based on observations arising from the CCTG’s MA.20 study of regional radiation therapy in early breast cancer (NCTNCT00005957).
The MA.39 trial will be supported by the Canadian Institute of Health Research, the Canadian Cancer Society Research Institute and the US National Cancer Institute. Recruitment into the study is anticipated to commence in Q3 or Q4 2017.
“The study concept has also been presented to the Breast International Group (BIG), which has expressed enthusiasm for this trial. BIG member groups will be surveyed for their interest and ability to participate in the trial,” said Dr Parulekar. Assuming that this initial interest is confirmed through the survey, the trial will be run by CCTG under the BIG umbrella. The luminal A subtype of breast cancer accounts for up to 40% of patients with node-positive breast cancer. If regional radiotherapy could be avoided in this group of patients, it would have substantial benefits, not only for women with breast cancer and their families but also for the healthcare system at large.