Shorter Therapy as Effective for DCIS Breast Cancer

TORONTO, ONTARIO--(Marketwired - Oct. 8, 2014) - In the first large, longer-term follow-up study of its kind, Sunnybrook researchers report that women with DCIS, the most common non-invasive form of breast cancer, do not have increased risk of recurrence if after surgery, they undergo shorter treatment time hypofractionated radiation therapy, instead of conventional whole breast radiation therapy.

The study is published in the International Journal of Radiation Oncology, Biology, Physics and a related abstract will be discussed/presented at the 2014 Best of ASTRO (American Society for Radiation Oncology) meeting later this month.

"Women diagnosed with ductal carcinoma in situ (DCIS) represent about 25 per cent of new patients. We hope our study findings will further inform and support the option to treat these individuals with a hyprofractionated approach with lower overall dose over a shorter time period, and with good preservation of physical appearance (cosmesis), and no added recurrence risk, with 10 years of follow-up, especially for invasive breast cancer," says Dr. Eileen Rakovitch, senior author of the study who is also a radiation oncologist and the head of the Breast Cancer Care team at the Louise Temerty Breast Cancer Centre, Sunnybrook's Odette Cancer Centre.

After breast-conserving surgery, a regimen of conventional whole breast radiation therapy is 50 Gy delivered in 25 fractions over 5 weeks. A regimen of post-surgery hypofractionated radiation therapy is 40 to 42.5 Gy delivered in 16 fractions over 3.5 weeks.

The researchers report the 10-year actuarial local recurrence-free survival rate was 86% for women treated with conventional radiation therapy and 89% for those who received hyprofractionated radiation therapy.

The retrospective study involved a cohort of 1, 609 women from the Ontario Cancer Registry from January 1, 1994 to December 31, 2003, who received treatment at multiple institutions across the province. After breast-conserving surgery, 971 received conventional regimens and 638 received hyprofractionated radiation therapy. Median follow-up time was 9.2 years.