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Researchers validate recurrence risk test for DCIS

December 12, 2014 Toronto

Researchers at Sunnybrook Health Sciences Centre and the Institute for Clinical Evaluative Sciences (ICES) working with a team of investigators from across Ontario have validated a multi-gene biomarker panel shown to predict the risk of recurrence among patients diagnosed with ductal carcinoma in situ (DCIS) who had breast-conserving surgery alone. The study findings are being presented today at the 2014 San Antonio Breast Cancer Symposium.

DCIS means that cells that line the milk ducts in the breast have developed cancer features. DCIS is considered non-invasive which means it has not spread through the walls of the milk ducts to surrounding breast tissue, but some DCIS can go on to become invasive cancer. To date, there is no definitive way to know which cases will recur as DCIS or will go on to invasive disease.

Goals of treatment for newly diagnosed women are to reduce the risk of local recurrence and invasive breast cancer, while preserving as much of the breast as possible. Most women will be treated with breast conserving surgery (removes the DCIS part of the breast tissue), usually followed by radiation therapy.

The researchers, who are leading work in DCIS, have validated Oncotype DX DCIS Score. The Oncotype DX DCIS score uses a molecular biomarker panel to formulate individualized estimates of 10-year risk of local recurrence in individuals with DCIS treated with breast conserving surgery alone.

“Currently clinical and pathological features do not reliably help identify individuals at low risk of recurrence after breast-conserving surgery. There is a great need to improve individualized treatment decisions to minimize both under and over treatment for these women,” says Dr. Eileen Rakovitch, lead investigator, radiation oncologist at Sunnybrook Health Sciences Centre and scientist at Sunnybrook Research Institute.

The researchers looked at 571 individuals diagnosed with pure DCIS who were treated with breast conserving surgery alone and had negative margins (no cancer cells are seen at the outer edge of the tissue that was removed). With a median follow-up of 9.6 years, the researchers’ report that the DCIS score was associated with local recurrence, regardless of estrogen receptor (ER) status, and provided independent information on local recurrence risk, beyond current clinical and pathologic variables.

Findings show that patients in the low risk DCIS score group had a significantly lower risk of developing a recurrence compared to individuals in the intermediate or high risk DCIS score groups. Every 50 point increase in DCIS was associated with a two-fold increase in the risk of developing recurrence.

DCIS comprises up to 25 per cent of mammographically-detected breast cancers. “It is our hope that this test will provide additional information to physicians and patients, and help guide them in more personalized treatment decisions,” says Dr. Rakovitch, also an adjunct scientist with ICES.

The study was done in collaboration with ICES. The study was supported by research grants from the Canadian Cancer Society Research Institute, and Genomic Health, Inc.

Sunnybrook Health Sciences Centre is inventing the future of health care for the 1.2 million patients the hospital cares for each year through the dedication of its more than 10,000 staff and volunteers. An internationally recognized leader in research and education and a full affiliation with the University of Toronto distinguishes Sunnybrook as one of Canada’s premier academic health sciences centres. Sunnybrook specializes in caring for high-risk pregnancies, critically-ill newborns and adults, offering specialized rehabilitation and treating and preventing cancer, cardiovascular disease, neurological and psychiatric disorders, orthopaedic and arthritic conditions and traumatic injuries. The Hospital also has a unique and national leading program for the care of Canada’s war veterans. For more information about how Sunnybrook is inventing the future of health care please visit us online at www.sunnybrook.ca About ICES

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.

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