The debate about overdiagnosis illustrates the limits of medical technology, Brawley said.

Although researchers can estimate the statistical rate of overdiagnosis, doctors treating actual patients can’t definitively tell which breast tumors need treatment and which might be safely ignored, Brawley said. So doctors tend to err on the side of caution and treat all breast cancers with surgery and, in many cases, radiation and chemotherapy.


An estimated 253,000 new cases of breast cancer will be diagnosed in U.S. women this year, with nearly 41,000 deaths, according to the American Cancer Society.

An additional 63,000 women will be diagnosed with ductal carcinoma in situ, also known as DCIS, which has some, but not all, of the typical traits of cancer. Although DCIS cells have changed to appear malignant under the microscope, they haven’t invaded surrounding tissue.

The American Cancer Society defines DCIS as the earliest stage of breast cancer, and women with the condition typically undergo the same treatment given to women with early invasive cancers. Although DCIS isn’t life-threatening, doctors recommend treating it to prevent it from becoming invasive.

Other experts note that DCIS carries such low risk that it should be considered merely a risk factor for cancer. Researchers are conducting studies to measure whether it’s safe to scale back treatment of DCIS.

KHN’s coverage related to aging and improving care of older adults is supported by The John A. Hartford Foundation.

Kaiser Health News, a nonprofit health newsroom whose stories appear in news outlets nationwide, is an editorially independent part of the Kaiser Family Foundation.

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