• Posted April 25, 2024

Breast Cancer Survivors Face Higher Odds for Second Cancer

People lucky enough to survive a breast cancer may still face heightened risks for other cancers later, a new study shows.

The researchers stressed that the absolute risk of a secondary cancer to any one survivor is still low. However, relative to folks who've never had breast cancer, the risk is raised.

"This is the largest study to date to look at the risk in breast cancer survivors of developing a second cancer," noted study senior author Antonis Antoniou, of the department of public health and primary care at the University of Cambridge in Britain.

His team looked at data on over 580,000 female and more than 3,500 male breast cancer survivors enrolled in the U.K.'s National Cancer Registration Dataset. They had all received their initial breast cancer diagnosis between 1995 and 2019.

First off, the team looked at the odds that a breast cancer survivor would go on to to be diagnosed with cancer in the previously unaffected breast.

Female breast cancer survivors had double the odds of a tumor arising in the other breast compared to women who'd never had breast cancer before, the team reported April 24 in the journal Lancet Regional Health – Europe.

For male survivors (in whom breast cancer is a much more rare disease), the odds of developing cancer in the other breast rose 55-fold, the study found.

As for other tumor types, female breast cancer survivors were found to have an 87% higher odds of developing endometrial cancer, a 58% higher risk of myeloid leukemia and a 25% upped odds for ovarian cancer, compared to women without any history of breast cancer.

A patient's age at first diagnosis of breast cancer also mattered: Women who had been diagnosed before the age of 50 faced an 86% higher odds for a second cancer later, whereas women first diagnosed after the age of 50 were only 17% more prone to secondary tumors, the data showed.

Why did age matter? It's possible that women who develop a breast cancer when young are more likely to carry cancer-linked genes than women whose cancers emerge later in life, Antoniou's team said.

Economics may also play a role in the risk of second cancers, with breast cancer survivors from poorer backgrounds having a 35% higher odds for a secondary tumor compared to women from the most affluent areas.

“This is further evidence of the health inequalities that people from more deprived backgrounds experience," said study lead author Isaac Allen, a PhD student at Cambridge.

"We need to fully understand why they are at greater risk of second cancers so that we can intervene and reduce this risk," he said in a Cambridge news release.

More information

Find out more about the care of breast cancer survivors at the American Cancer Society.

SOURCE: University of Cambridge, news release, April 24, 2024