Women with diabetes more likely to be diagnosed with advanced stage breast cancer

Diabetes is associated with more advanced stage breast cancer, according to a new study by the Institute for Clinical Evaluative Sciences (ICES) and Women’s College Hospital.

The findings, published today in the journal Breast Cancer Research and Treatment, confirm a strong link between diabetes and later stage breast cancer at diagnosis for Canadian women.

“Our findings suggest that women with diabetes may be predisposed to more advanced stage breast cancer, which may be a contributor to their higher cancer mortality,” said Dr. Lorraine Lipscombe, a scientist at ICES and Women’s College Research Institute.

In the study, Dr. Lipscombe examined stage at diagnosis among women aged 20-105 years who were newly diagnosed with invasive breast cancer between 2007 and 2012.

From an analysis of more than 38,000 women with breast cancer, 6,115 (15.9 per cent) of the women had diabetes. Breast cancer patients with diabetes were significantly more likely to present with advanced stage breast cancer than those without diabetes. Women with diabetes were 14 per cent more likely to present with Stage II breast cancer, 21 per cent more likely to present with Stage III breast cancer, and 16 per cent more likely to present with Stage IV than to present with Stage I. The results also show lower mammogram rates in women with diabetes, which could account for later stage disease. Women with diabetes also had a higher risk of lymph node metastases (spreading of the cancer) and larger tumors than women without diabetes.

“In addition, the risk of advanced stage breast cancer was greatest in younger women and those with longer-standing diabetes,” added Lipscombe.

The study showed that the majority of diabetes patients presented with Stage II or III breast cancer, which translated into a 15 per cent decrease in five-year survival for diabetes patients at the time of cancer diagnosis.

The researchers suggest that breast cancer screening and detection practices may need to be modified in patients with diabetes to reduce the chances of later-stage detection.

The study was funded by the Canadian Institutes for Health Research and the Ontario Institute for Cancer Research.

“The association between diabetes and breast cancer stage at diagnosis: a population-based study,” was published today in Breast Cancer Research and Treatment.

Authors: Lorraine L. Lipscombe, Hadas Fischer, Peter C. Austin, Longdi Fu, R. Liisa Jaakkimainen, Ophira Ginsburg, Paula Rochon, Steven Narod, Lawrence Paszat.

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare 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.

Women’s College Hospital (www.womenscollegehospital.ca) is advancing the health of women and improving healthcare options for all by delivering innovative models of ambulatory care. Fully affiliated with the University of Toronto, the hospital is Canada’s leading academic, ambulatory hospital and a world leader in women’s health. With more than 800 physicians, nurses and health professionals, the hospital offers a range of specialized clinics and programs that are bridging the gaps in the health system. Women’s College Hospital is helping to keep people out of hospital by being at the forefront of cutting-edge research, diagnosis and treatment that will help prevent illness and enable patients to manage their health conditions. This healthcare enables Canadians to live healthier, more independent lives. At the Women’s College Research Institute, scientists combine science and patient care to develop innovative solutions to today’s greatest health challenges.

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