Chemotherapy helps many women survive breast cancer, but new research suggests the treatment may also accelerate biological aging and raise the risk of earlier death from other causes.
Patients receiving the most intensive chemotherapy regimens could lose more than nine years of healthy life due to this accelerated aging, according to population-based simulation modeling published November 10, 2026, in JAMA Network Open. The study, conducted by researchers at Georgetown University’s Lombardi Comprehensive Cancer Center and colleagues, marks the first time investigators have estimated the lifetime balance between curing breast cancer and the subsequent acceleration of biological age.
Cellular Damage and Life Year Losses
Female breast cancer survivors make up the single largest segment of the 18.6 million cancer survivors in the United States. While certain chemotherapy drugs successfully extend survival, they trigger a secondary crisis of treatment-induced molecular damage to cells and organs.
“However, some forms of chemotherapy that extend survival have triggered a secondary crisis: treatment-induced molecular damage to the body’s cells and organs, causing acceleration of biological age,” Jeanne Mandelblatt, senior author and director of the Georgetown Lombardi’s Institute for Cancer and Aging Research, said.
Mandelblatt noted that this biological aging results in a loss of healthy life years from the earlier onset of conditions like frailty and cognitive problems. The risk of dying from non-cancer causes was estimated to overtake breast cancer mortality about 16 years earlier than expected based on chronological age alone.
The computer simulation modeled 400 million U.S. women diagnosed with breast cancer between ages 30 and 79. The Georgetown researchers compared cytotoxic chemotherapy regimens that caused heavier cellular damage against less intensive options. Women treated with anthracyclines were estimated to lose a median of 7.6 additional life years from aging-related diseases.
Senescent Cells Drive Long-Term Risks
The accelerated aging stems directly from how chemotherapy damages normal tissues outside the tumor. The treatment increases the accumulation of senescent cells, which are damaged cells that stop dividing but resist cell death.
“The key to our methodology is accounting for the fact that while chemotherapy improves breast cancer survival, treatment can also increase damage to normal tissues.
This affects many aging systems, including increasing the number of senescent cells, which are damaged cells that have stopped dividing and are also resistant to cell death,” Swarnavo Sarkar, lead author and a member of I-CARE at Lombardi, explained. “Senescent cells secrete biological molecules that cause several aging-related diseases through added tissue damage and inflammation.”
The research team tracked biological age by analyzing blood levels of the p16 protein, a common biomarker of senescence. Investigators selected p16 because published research and laboratory evidence indicate that clearing p16-rich cells can increase lifespan. The analysis was conducted through the Cancer Intervention and Surveillance Modeling Network, a 25-year-old consortium of National Cancer Institute-sponsored investigators.
Personalized care may mitigate accelerated aging effects
Study authors emphasize that patients should not avoid chemotherapy, as the treatments remain vital for curing cancer and saving lives. Instead, the findings point toward personalized survivorship care designed to mitigate aging effects.
“This is particularly salient now, since physical activity and medications being used for other purposes show promise in slowing accelerated aging in breast and other cancer survivors, which may recoup the loss of life years estimated in this study,” Mandelblatt stated. Future clinical work will evaluate testing biological age after treatment ends to guide lifestyle changes or therapeutic interventions.
Researchers are also expanding their computer models beyond chemotherapy. Sarkar said that upcoming studies will investigate how radiotherapy, immunotherapies, targeted therapies, and hormonal treatments impact biological aging over long periods.
U.S. breast cancer survivor population continues to expand
The population of female breast cancer survivors in the United States continues to expand alongside advances in early detection and treatment. The American Cancer Society projects that the total count of female breast cancer survivors could reach 5.3 million by January 2035, representing an increase of 1 million from 2025 figures. The American Cancer Society also estimated 382,640 new breast cancer cases and 42,140 deaths in the U.S. for the year.
Frequently Asked Questions
Does the study suggest patients should skip chemotherapy?
No. Researchers emphasize that treatment choices must remain focused on curing cancer, as intensive regimens successfully improve overall survival rates despite their long-term cellular costs.
How did researchers calculate biological age acceleration?
Investigators used a population simulation model incorporating data on post-chemotherapy cellular senescence measured through blood levels of the p16 protein across women aged 30 to 79.
What treatments will researchers study next?
Georgetown Lombardi investigators plan to expand their simulation methodology to evaluate how radiotherapy, immunotherapies, targeted therapies, and hormonal treatments affect biological aging over time.
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