The physiological changes in the process of aging are the sum of multiple factors affecting each individual to a different extent. The result of these changes and the impact on pharmacokinetics (PKs) and pharmacodynamics (PDs) of systemic anticancer treatment are linked mechanistically to altered drug handling and altered physiological reserve. The risk of death does increase with chronological age, which is consistent with a progressive and independently evolving aging process; yet aging is better reflected by the biological age than the calendar age. Determining the biological age or the functional status of an elder is one of the challenges facing those involved in the treatment of the elderly as no universal instrument or test is available to estimate the individual biological age (as discussed in Chap. 4). No treatment should commence, especially concerning cytotoxic anticancer therapy, before careful evaluation of the physiological reserve of an older individual has been assessed, while during treatment an ongoing routine must assure that in case of preceding under- or overestimation of the assumed biological age of a patient, it is recognized in an early phase and treatment is adjusted accordingly.,
Department of Medical Oncology

Hamberg, A.P, de Jonge, M.J.A, & Seynaeve, C.M. (2010). Impact of the physiological effects of aging on the pharmacokinetics and pharmacodynamics of systemic breast cancer treatment. doi:10.1007/978-1-84800-265-4_6