Study calls early stage breast cancer treatment into question

New research has called a common (and often disfiguring) treatment for early stage breast cancer into question.

A study published in the journal JAMA Oncology found that women with stage 0 breast cancer (also known as ductal carcinoma in situ, or DCIS) who undergo treatment have the same likelihood of dying of breast cancer within 20 years as women in the general population.

DCIS is diagnosed after abnormal cells are found in the breast’s milk ducts and is typically detected by mammogram. It now makes up about one in five new breast cancer diagnoses, according to the American Cancer Society, and nearly all women diagnosed at this stage can be cured.

For the study, researchers analysed previously analysed data from the Surveillance, Epidemiology, and End Results database of more than 108,000 women who received a diagnosis of DCIS from 1988 to 2011. Their risk of dying of breast cancer was then compared against that of women in the general population.

RELATED: Could the pill protect against cancer?

Women with the diagnoses were treated with a lumpectomy (a surgical treatment that removes a lump from the breast), lumpectomy with radiation therapy, or mastectomy (full surgical removal of the breast). But researchers discovered that the rate of dying from breast cancer within 20 years was the same for all three groups - 3.3 per cent - which is similar to that of the general population.

The findings don’t seem to be shocking to the medical community. “We’ve always had a sense that perhaps we were overtreating DCIS,” Maggie DiNome, MD, director of the Margie Petersen Breast Center at John Wayne Cancer Institute at Providence Saint John’s Health Center in Santa Monica, Calif., tells Yahoo Health.

The detection of DCIS is fairly new and doctors are “still trying to understand with the disease is about,” DiNome says. And while they’re learning more, they’re erring on the side of caution.

Susan Minton, clinical director of breast medical oncology at the Moffitt Cancer Center, tells Yahoo Health the findings are important, but they don’t mean that women should do nothing if they receive a DCIS diagnosis.

Here’s why: There are a lot of DCIS tumors that do not evolve into evasive cancers and would likely benefit from less invasive treatment. However, there are some forms of DCIS that will progress into invasive cancers - doctors just don’t yet have the technology to determine what form a patient’s DCIS will take. “That is the reasoning behind the treatment,” Minton says.

Some women may have a cancer recurrence even after undergoing a lumpectomy, lumpectomy with radiation treatment, or mastectomy, but the odds are fairly low.

GALLERY: 10 Biggest diet mistakes

Study author Steven Narod, MD, director of the Familial Breast Cancer Research Unit at the Women’s College Research Institute, tells Yahoo Health that patients have the lowest risk of cancer recurrence with a mastectomy (less than 1 per cent), followed by a lumpectomy with radiation therapy (3 per cent), and lumpectomy with no radiation (5 per cent).

Which treatment should a DCIS patient choose? Narod says he tells his patients that, if their goal is to live as long as possible, a lumpectomy is fine. However, if they’re concerned that the cancer will come back, they should have a mastectomy. “A lot of women have a mastectomy because of their fear of cancer, but for DCIS, it has no impact on whether you live or die,” he says.

Before more research is done, Minton says doctors will likely continue to recommend the usual treatments for DCIS.

“Until we determine a better way of defining who is clearly at risk and who isn’t, we need to be cautious about saying it’s OK not to treat DCIS,” she says. “The standard of care is to treat. We want to prevent those cancers from returning.”

This article originally appeared on Yahoo Health