Practice-changing cancer trial shows additional radiation decreases cancer recurrence

04 June 2011

Toronto -

A Canadian-led clinical trial has found that additional radiation treatment improves disease-free survival in women with early breast cancer and reduces the risk of cancer recurrence, a finding that could change the standard treatment for this group of patients. The trial was led by the NCIC Clinical Trials Group, which is funded by the Canadian Cancer Society.

The study enrolled more than 1,800 women who had been treated with breast-conserving surgery (lumpectomy) and adjuvant chemotherapy or endocrine therapy. In the trial, the women received either whole breast radiation alone or whole breast radiation plus additional radiation to the surrounding lymph nodes, called regional lymph node irradiation.

After a five-year follow-up, interim analysis of the data showed a greater than 30 per cent improvement in disease-free survival for those receiving additional radiation therapy. This included a 41 per cent lower rate of cancer recurrence in the breast and lymph nodes and a 36 per cent lower rate of cancer recurrence in other parts of the body.

The results were presented today at the annual meeting of the American Society of Clinical Oncology.

“For women with node positive breast cancer who face a risk of recurrence, these findings provide an important new treatment option,” says Dr Christine Williams, Director of Research, Canadian Cancer Society. “We expect this research to change clinical practice so that more women survive and thrive after cancer.”

Current treatment for women with node-positive breast cancer has been breast-conserving surgery plus removal of the lymph nodes, followed by radiation to the breast. If a woman’s cancer is considered high-risk, such as a tumour larger than five cm or more than three positive axillary (in the armpit) nodes, she often receives regional nodal irradiation (RNI). Until now, however, the benefit of adding RNI for women with one to three positive nodes has been unclear.

This trial is just one of three conducted by the NCIC CTG and funded by the Canadian Cancer Society which this year has been selected as “Best of ASCO”. The other two studies include a landmark breast cancer prevention trial and one which found a more effective way to treat prostate cancer. Studies featured in Best of ASCO have the potential to change clinical practice around the world.

Breast cancer is the most common cancer among Canadian women (excluding non-melanoma skin cancer). In 2011, an estimated 23,400 women will be diagnosed with breast cancer and 5,100 will die of it.

The NCIC Clinical Trials Group is a national research program of the Canadian Cancer Society and receives programmatic funding, including for this trial, from the Canadian Cancer Society Research Institute. Additional support for the trial was provided by the US National Cancer Institute/Cancer Therapy Evaluation Program and the Canadian Breast Cancer Research Alliance.

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For more information, please contact:

Anthony Fuchs

Director, Communications

Canadian Cancer Society

Phone: 416 934-5339