Cancer is primarily a disease of the elderly. Greater than 60% of new cancers occur in people aged >65 years.1 The incidence rate for all sites triples in persons ages 60 years to 70 years, compared with individuals aged 40 to 59 years.2 Moreover, as the proportion of the US population aged ≥65 years increases, even greater numbers of older individuals will be diagnosed with cancer.3, 4 Improved early detection and treatment have also increased the number of people who have cancer for an extended period of time. Of the current 10 million cancer survivors, 60% are aged ≥65 years, and >16% of US adults aged ≥65 years are cancer survivors.5 Given these large numbers and the potential vulnerability of older adults, older cancer survivors have become an especially important group to study.
Survivorship represents a relatively new way of thinking about cancer as it is experienced by those who are diagnosed and treated for this disease. In the past, poor survival rates for the majority of cancers resulted in thinking of cancer as a “death sentence.” However, improved survival rates have made a survivorship orientation more realistic. This, along with the perspective of cancer as a chronic disease,5, 6 has resulted in survivorship becoming a new focus for both the clinicians who treat cancer patients and the scientists who study them.
The term “survivor” now refers not only to those who have lived for an extended period of time after treatment, but also includes newly diagnosed individuals as well as those who are in treatment, have completed treatment, or are in remission. This change in orientation and language has been adopted and promoted by the American Cancer Society and the National Coalition of Cancer Survivors. In fact, the National Cancer Institute's Office of Cancer Survivorship defines a survivor as anyone who has been diagnosed with cancer.7 Taken together, the definition of a cancer survivor now includes a range of individuals beginning with those newly diagnosed to those who have been free of cancer for decades.
This article discusses the physical and mental functioning of older cancer survivors across a temporal continuum. The first part reviewed research on survivors age ≥65 years who are relatively newly diagnosed (≥3 years) with cancer. The second part reviewed research on older survivors who represent long-term survivors. In reviewing the research, we focused on published research based on samples of cancer survivors aged >60 years only or research that specifically compared survivors of different age categories. We began our search with recently published articles identified through PubMed and added articles cited in these publications. This article did not attempt to provide an exhaustive review of all published research on older cancer survivors, but rather to present a sense of what is currently known regarding older cancer survivors, the limitations of this research, and directions for future research.
We should mention several factors that make comparisons across studies particularly challenging. One challenge is differing age distributions and cutpoints across studies. The most common cutpoint for older survivors is 65 years of age, but this is not used uniformly. Second, samples differ in their time since diagnosis. Some smaller studies have samples comprised of survivors with very explicit time intervals from diagnosis (eg, 3 months, 1 year), whereas other large cohort studies may have wider ranges (eg, any cancer survivor). Third, some studies control for important covariates, and others do not. As seen in this review, these covariates (particularly comorbidities and symptoms) are important considerations in studying older survivors. Fourth, studies involve different cancer sites. The majority of studies focus on breast cancer survivors, but others include survivors of multiple cancer sites. As seen in these studies, quality of life (QOL) issues vary by cancer site. Despite these challenges, there are some consistent patterns to the findings, and those patterns are the focus of this article.