Chemotherapy May Accelerate Biological Aging in Breast Cancer Survivors, Modeling Study Finds

A study published November 10, 2026, in JAMA Open Network raises an uncomfortable question about one of medicine's clearest success stories: whether the chemotherapy that helps women survive breast cancer also makes their bodies age faster than the calendar says they should.

The work comes from researchers at Georgetown University's Lombardi Comprehensive Cancer Center and colleagues. Its senior author is Jeanne Mandelblatt, MD, MPH, director of Lombardi's Institute for Cancer and Aging Research, known as I-CARE. Its lead author is Swarnavo Sarkar, PhD, a member of I-CARE. The team says it is the first to use population-based simulation modeling to estimate the lifetime balance between the benefit of curing breast cancer and the possible cost of accelerated biological aging.

The scale of the group involved is large. Female breast cancer survivors make up the single largest segment of the 18.6 million cancer survivors in the United States. The researchers argue that some chemotherapy regimens that extend survival have also set off a secondary problem: molecular damage to cells and organs that pushes biological age ahead of chronological age. That acceleration can persist for years, and its effects may not become visible for many years after treatment. Mandelblatt says it can mean fewer healthy years, through earlier onset of age-related conditions such as frailty and cognitive problems.

Sarkar explained the mechanism the model is built on. Chemotherapy improves survival, but it can also damage normal tissue, including by increasing the number of senescent cells. These are damaged cells that have stopped dividing and resist cell death. They secrete molecules that drive several age-related diseases through added tissue damage and inflammation.

To put numbers on this, the investigators drew on published data linking chemotherapy to blood levels of p16, a common biomarker of senescence. They used it to estimate survivors' biological age across the rest of their lives. They chose p16 because good published data exist for it, and because laboratory evidence suggests that clearing p16-rich cells could extend lifespan. Other aging markers are under study and could be used in later work.

The simulation covered women aged 30 to 79. It compared chemotherapy types that cause more cellular damage, described as more cytotoxic, with those that cause less, along with their differing effects on biological age. Women who received the most cytotoxic regimens were estimated to lose an average of 9.4 remaining life years, because aging-related diseases arrive earlier.

Mandelblatt stresses that treatment decisions will continue to be driven by the chance of cure. What she hopes is that the model will guide future studies of testing biological age once treatment ends, with the aim of personalized survivorship care that limits the aging effects of therapy and improves health over a survivor's lifetime. She notes that physical activity and medications used for other purposes show promise in slowing accelerated aging in breast and other cancer survivors, which could recover some of the life years the study estimates are lost.

The analysis was possible because Mandelblatt and Sarkar belong to CISNET, the Cancer Intervention and Surveillance Modeling Network. It is a 25-year-old consortium of National Cancer Institute-sponsored investigators who use simulation modeling to study cancer prevention, screening and treatment and their effects on population incidence and mortality.

Sarkar says the team has two next steps. One is extending the method to other breast cancer treatments, including radiotherapy, immunotherapies, targeted therapies and hormonal treatments, which also appear to speed aging, with effects that may last for years. The other is adding survivor characteristics to the model, to inform future conversations about individual outcomes.