Study links breast cancer chemotherapy to faster biological ageing

Chemotherapy helps many women survive breast cancer, but it may also speed up biological ageing and raise the risk of earlier death from other causes, according to new research from Georgetown University's Lombardi Comprehensive Cancer Center and colleagues. The study was published in JAMA Network Open.

The team used population-based simulation modelling to estimate the lifetime balance between the benefit of curing breast cancer and the possible acceleration of biological ageing. The model was based on women aged 30 to 79 and compared chemotherapy regimens that cause more cellular damage with those that cause less.

Researchers drew on data linking chemotherapy to blood levels of the p16 protein, a biomarker of senescence, to estimate survivors' biological age over their remaining lives. Senescent cells are damaged cells that have stopped dividing and resist cell death, and chemotherapy can increase their number.

Women who received the most cytotoxic regimens were estimated to have lost 9.4 remaining life years on average, because ageing-related diseases such as frailty and cognitive problems begin earlier. Jeanne Mandelblatt, director of Georgetown Lombardi's Institute for Cancer and Aging Research, said: "Chemotherapy-induced biologic aging can persist for years, and the effects of this acceleration are not visible for many years."

Lead author Swarnavo Sarkar said: "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." He also said senescent cells release molecules that cause several ageing-related diseases through added tissue damage and inflammation.

The researchers said physical activity and some medications normally used for other purposes show promise in slowing accelerated ageing in cancer survivors, and may recoup the estimated loss of life years. They are considering whether added treatment and lifestyle changes could slow or reverse it.

Next, the team plans to extend the method to other breast cancer treatments, including radiotherapy, immunotherapies, targeted therapies and hormonal treatments. It also plans to test biological age after treatment ends to support personalised survivorship care, and to include survivor characteristics to guide conversations about individual outcomes.

In the United States, female breast cancer survivors are the largest group among 18.6 million cancer survivors. The American Cancer Society projects 382,640 new breast cancer cases and 42,140 deaths this year, according to The Independent.