Overdiagnosis of Breast Cancer in Older Women—and Unnecessary Treatment—Is Widespread: Study

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More than 240,000 women in the United States will be diagnosed with breast cancer this year, and most will likely start treatment immediately. But according to new research, that may be a mistake.

Breast cancer in women ages 70 to 85 is often overdiagnosed, which may lead to unwarranted worry and unnecessary and intensive treatments such as surgery and chemotherapy that don’t improve quality of life.

“Overdiagnosis refers to a phenomenon where we find breast cancers through screening that never would have caused symptoms,” said Dr. Ilana Richman, the paper’s lead author and an assistant professor of medicine at the Yale School of Medicine. “Overdiagnosis can occur when cancers grow very slowly or if a person’s life expectancy is short.”

Reevaluating Screening Practices for Older Patients

Published in the Annals of Internal Medicine, the research underscores the importance of reevaluating screening practices and engaging in informed discussions with patients.

Although mammography is a standard screening method for breast cancer, the study highlights a gap in research for older women. Individuals over 74 have frequently been excluded from large randomized screening trials, leaving uncertainty regarding the full spectrum of screening benefits and potential drawbacks.

The study, involving 54,635 women aged 70 and above, analyzed breast cancer diagnoses and related fatalities over a 15-year follow-up period.

The results indicate a significant likelihood of overdiagnosis among older women. Specifically, an estimated 31 percent of women aged 70 to 74 were overdiagnosed, as well as 47 percent of those aged 75 to 84 and 54 percent of those aged 85 and older.

“That finding points to a real need for better tools to identify which women may benefit from screening and which breast cancers are unlikely to be progressive so that we can avoid overtreatment,” Dr. Richman said.

The Challenge of Overdiagnosis: Risks Versus Benefits

There are two primary challenges to putting the study findings into clinical practice.

First, balancing the risks of overdiagnosis against potential screening benefits is difficult on an individual basis, given the current uncertainties in the data, according to Dr. Richman.

Second, discussing the concept of overdiagnosis with patients presents communication difficulties, she added. As an abstract, unfamiliar idea that can’t be directly observed, it doesn’t fit neatly into busy clinic visits.

To address these issues, tools are needed to support patient–provider conversations and provide personalized information to women, Dr. Richman said.

“[This] can help ensure that decisions about screening are concordant with our patients’ values.”

Breast cancer rates peak among women aged 70 to 74, according to the American Cancer Society. The risk decreases as women age into their 80s, partly because women tend to die from other causes instead, such as heart disease or other cancers.

Improved Detection Comes at a Cost of Surging Overdiagnosis Rates

Recent technological advancements—such as three-dimensional mammography, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PT) scans—have increased detection rates.

However, the sensitivity of these advanced images leads them to detect a wide range of abnormalities, including noncancerous lesions, slow-growing tumors, and lesions that may spontaneously regress.

The introduction of screening programs has led to sharp rises in invasive breast cancer diagnoses—even for abnormalities that typically naturally regress.

In the present paradigm, once cancer is detected, it’s typically treated aggressively with surgery, radiation, or chemotherapy. However, this amplified volume of treatment increases the risks of complications and financial burden, especially for older patients. It also unnecessarily exposes women to repeated radiation from mammograms.

A mammogram is essentially an X-ray, a form of ionizing radiation that has raised concerns due to its risk of causing radiation-induced breast cancer.

The central dilemma is that increased detection doesn’t equate to improved outcomes. More research is needed to determine appropriate screening guidelines, especially for women over 75. The goal is to identify cancers destined to progress while avoiding overtreatment of regressive or indolent lesions.

In May, the U.S. Preventive Services Task Force, an independent panel of experts that provides screening guidelines for clinicians, issued new recommendations. The experts advised starting routine breast cancer screening at age 40 instead of 50. However, they also acknowledged the need for further research on screening benefits and harms to determine appropriate guidelines for women over 75.