Knowing that mastectomy rates vary across Canada is an important first step in understanding how care can be improved. (Eric Gaillard/Reuters)

Mastectomy rates in Newfoundland and Labrador are almost double the national average and nearly triple the rate in Quebec, a new study shows.

Researchers looked at rates of breast cancer surgery, such as mastectomy and lumpectomy, based on data from nearly 58,000 women in every province and territory who had breast cancer surgery between 2007-08 and 2009-10.

They concluded the rates vary greatly across Canada, and may be tied to the distance a patient lives from a radiation treatment facility.

Breast removal rates for a first surgery for invasive breast cancer ranged from 69 per cent in Newfoundland and Labrador to 26 per cent in Quebec, with the national average at 39 per cent.

"Certainly, the distance from a radiation facility is one of the factors that seems to be driving that, in that more patients in Newfoundland are farther away," said Dr. Geoff Porter, a professor of surgery at Dalhousie University in Halifax, who co-authored the research published in Tuesday’s issue of the Canadian Medical Association Journal Open.

"However, that certainly doesn't explain it all. There is significant interprovincial variation in Canada for several aspects of surgical breast cancer care."

Key first step

Porter called the findings an important first step in understanding how care can be improved.

Women with longer travel times to a radiation facility, which are usually in major cities, were more likely to have a mastectomy. Long courses of radiation are generally recommended after lumpectomies, and travel time appeared to significantly reduce use of less-invasive surgery.

The research also showed that the most affluent women were less likely to have a mastectomy compared with the least affluent, although Porter said the reason for that was unclear.

"I think what our study shows is that surgery in Newfoundland is more aggressive than other provinces by virtue of the fact that more patients are having mastectomies."

CBC contacted Eastern Health on Monday for reaction to the research. A spokesperson said Tuesday no one was available for comment.

The study was conducted by the Canadian Institute for Health Information and the Canadian Partnership Against Cancer.