Over the last century, life expectancy has been steadily rising. In 2003, the US Vital Statistics estimated median life expectancy for 65-year-old men to be 17 years; for 70-year-olds it was 13 years, for 75-year-olds it was nine years and for 80-year-olds it was seven years.7 This expansion in life expectancy, coupled with increased incidence of cancer, is having a profound effect on the prevalence of cancer.
The risk of developing cancer increases with ageing.1 Over 50% of all new cancer cases are diagnosed in people aged 65 years or older, and over 60% of all cancer deaths occur in this group of the population.8 Despite this, cancer diagnosis and treatment in the elderly has been under-researched, with elderly patients frequently being excluded from clinical trials.5 Only a small subset of geriatric patients are being entered into clinical trials. Thus, elderly patients are still managed on the basis of assumptions based on a younger population group.1 Elderly patients with cancer should be assessed and treated differently from younger patients, as age-related physical changes affect the biology of cancer but also the physiology of elderly patients. These should be factored in while planning treatment.1,9,10 Hence, older patients cannot be managed in the same way as their younger counterparts due to concomitant and possibly multiple medical problems.11
Ageing is a complex, heterogeneous and highly individualised process. A person’s age alone does not always predict his or her physiological decline. This is due in part to the effect of co-morbidity on ageing.12 Patients of the same chronological age can differ greatly in physiological age and other aspects of ageing.9 Time of onset is affected by multiple factors including diet, race, sex, physical activity, habits and hormonal effect.1,26 The hallmark of senescence is decreased functional reserve of individual organs and the reduced ability of these organs to cope with the challenge.1 Ageing is associated with a decrease in gastrointestinal motility, splanchnic blood flow, secretion of digestive enzymes and mucosal atrophy, which can result in a reduced drug absorption rate.12–14