Secondary Prevention of Cancer in the Older Individual

Abstract

The incidence and the mortality of cancer increase with age. This article explores the possibility of decreasing cancerrelated mortality in the aged with secondary prevention of cancer deaths that entails early diagnosis of cancer through the screening of asymptomatic older individuals. We establish that screening of asymptomatic individuals should be based on physiologic rather than chronologic age that may be estimated from a comprehensive geriatric assessment and possibly with the utilization of biologic markers of aging. It is reasonable to offer some form of screening for lung and colorectal cancer to individuals with a life expectancy of at least five years and screening for breast and prostate cancer to women and men respectively with a life expectancy of at least ten years. The ideal number of screening sessions and the ideal interval between screening sessions is unestablished. The aging of the population, the diversity of the older population, the development of new and more sensitive screening interventions, the discovery of new biologic markers of cancer and age represent the main challenges in studying the value of cancer screening in the aged. Probably the most reliable information may be obtained from rapid-learning databases in which information related to each person's physiologic age is included. Worldwide, the incidence and prevalence of cancer increase with age [1]. In the meantime the risk of cancer-related mortality increases with age at diagnosis [2-4]. As the world population is aging, cancer in the older person is an ever more common problem, and the reduction of cancer deaths in older individuals represents the most urgent goal of cancer control. In this article we explore secondary cancer prevention as representing a strategy to reduce the risk of mortality in the aged.This hypothesis is based on four considerations: i. Several studies showed that the practice of screening asymptomatic individuals for cancer becomes less common with the aging of the population [5]. ii. The average life expectancy of the Western population is rapidly increasing1. Consequently the benefits of early detection of cancer that emerges several years after diagnosis may be present even for those undergoing screening at an advanced age. iii. New forms of cancer treatment, including minimally invasive surgery [6], stereotactic radio surgery [7], and targeted systemic therapy [8], are associated with decreased risk of complications. They may be safely utilized in individuals with limited tolerance of stress who might be hurt by more aggressive treatments. It is now possible to personalize cancer screening according to individual life expectancy and tolerance of stress, as the estimate of a person's physiologic age is becoming more precise [1,9]. After reviewing the principles and the effectiveness of cancer screening and early detection, this article will explore the benefits and risks of secondary cancer prevention in older individuals. In particular we will review the current evidence and the limitations of previous clinical trials. At the end we will propose a conceptual framework to guide the screening of older individuals for cancer, and we will propose a research agenda.