Background: Cancer and its treatments may accelerate aging in survivors; however, research has not examined epigenetic markers of aging in longer term breast cancer survivors. This study examined whether older breast cancer survivors showed greater epigenetic aging than noncancer controls and whether epigenetic aging related to functional outcomes.Methods: Nonmetastatic breast cancer survivors (n = 89) enrolled prior to systemic therapy and frequency‐matched controls (n = 101) ages 62 to 84 years provided two blood samples to derive epigenetic aging measures (Horvath, Extrinsic Epigenetic Age [EEA], PhenoAge, GrimAge, Dunedin Pace of Aging) and completed cognitive (Functional Assessment of Cancer Therapy‐Cognitive Function) and physical (Medical Outcomes Study Short Form‐12) function assessments at approximately 24 to 36 and 60 months after enrollment. Mixed‐effects models tested survivor‐control differences in epigenetic aging, adjusting for age and comorbidities; models for functional outcomes also adjusted for racial group, site, and cognitive reserve.Results: Survivors were 1.04 to 2.22 years biologically older than controls on Horvath, EEA, GrimAge, and DunedinPACE measures (p = .001–.04) at approximately 24 to 36 months after enrollment. Survivors exposed to chemotherapy were 1.97 to 2.71 years older (p = .001–.04), and among this group, an older EEA related to worse self‐reported cognition (p = .047) relative to controls. An older epigenetic age related to worse physical function in all women (p < .001–.01). Survivors and controls showed similar epigenetic aging over time, but Black survivors showed accelerated aging over time relative to non‐Hispanic White survivors.Conclusion: Older breast cancer survivors, particularly those exposed to chemotherapy, showed greater epigenetic aging than controls that may relate to worse outcomes. If replicated, measurement of biological aging could complement geriatric assessments to guide cancer care for older women.

Thanks to the global improvement of health care and living conditions, the world population is aging. Already, in developed countries half of the cancers occur in patients aged 70 and older. In booming Asian nations, such as South Korea, the aging trend is particularly striking, and therefore geriatric oncology is rapidly coming at the foreground of oncology practice. As older patients have a very variable health status, the need for proper integration of an oncologic and a geriatric approach has become increasingly clear. The last two decades have seen the development of geriatric oncology programs and research, which we review here. An increasing amount of data is making clear that a geriatric assessment identifies many problems in older people with cancer, adds prognostic information, and might improve the outcomes of these patients. The near future will likely deliver the following: Operationalization of geriatric assessment into assessment and decision tools, as well as multidisciplinary interventions, in oncology; cooperation of aging and cancer research in the understanding of cancer biology, aging physiology, pharmacology of anticancer drugs; improved clinical study designs; development of geriatric oncology programs, and screening tools accessible to the private practitioner.