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We really need to rethink how we diagnose and treat breast cancer

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We have more evidence that the way we deal with breast cancer is all wrong.

A new study published today in JAMA Oncology found that the radiation and mastectomy surgeries that thousands of women with early-stage breast cancer undergo may not save lives.

Women who are diagnosed with ductal carcinoma in situ, a form of cancer in the milk ducts of the breasts, and who undergo radiation and surgeries to remove their breasts don't reduce their chances of dying from the disease. Overall, the researchers found that 97 percent of the 100,000 women diagnosed with it are still alive 20 years later — rates similar to the overall population.

This study comes one month after JAMA published research that showed mass mammography screening programs lead to more diagnoses of the disease but not fewer deaths:

Extent of screening, breast cancer incidence, and mortality in women 40 years and older in 547 US counties. While diagnosis has increased with mass screening, mortality has remained stubbornly stable.

(JAMA Internal Medicine)

Taken together, these studies suggest we've gotten much better at finding breast cancers early on and telling more women they have it. (DCIS, often referred to as "stage zero," now accounts for about a quarter of all breast cancers.) But the treatments that women then receive may not be helping them lead longer and healthier lives.

We need to rethink how we view and treat early-stage breast cancer

DCIS is currently treated by removing the part of the breast with cancerous cells (a lumpectomy) and following up with radiation. Some patients worry about potential spread and choose to undergo a single or double mastectomy, which can remove the entire breast.

But overall, the surgeries that up to 60,000 women undergo each year have not been followed by a reduction of later-stage disease and death.

The implication from this study, said lead author Steven Narod, of the Women’s College Research Institute, is that women who are diagnosed early on may not need to undergo radical treatments. "Beyond (lumpectomies), further treatment doesn’t reduce death," he said.

In the study, the women who were treated for the cancer had nearly the same chances of dying from breast cancer as the general population — about 3.3 percent. So their treatments didn't alter the course of the disease or lower their risk of death.

There is a subset of women who had a different experience. As an accompanying editorial points out, when DCIS is diagnosed before the age of 35 or even 40 years, a woman's risk of dying is actually elevated — so these women might be treated differently than women who are diagnosed when they're slightly older. The risk of death was also higher among black women.

Still, the authors wrote, enough science has accumulated to suggest "aggressive treatment (radiation therapy after lumpectomy) of almost all DCIS does not lead to a reduction in breast cancer mortality."

For Dr. Gilbert Welch, author of Less Medicine, More Health, the findings suggest we need to rethink how we view and treat breast cancer. "DCIS is probably best viewed not as cancer, but as a risk factor for cancer — and not a terribly strong one. It's nothing like smoking in lung cancer or the BRCA mutation in ovarian and breast cancer," he said.

This new data should prompt discussions about how we deal with stage 0 breast cancer going forward. "In the future," Welch added, "we may treat it as [a risk factor]. But now we treat it like cancer."