Special Feature

Cancer in Older Persons: Clinical Challenges in Patients Older than 65

By Rosemary Yancik, PhD

Aging is a high-risk factor for cancer. most of the major tumors affect persons in their later years of life (i.e., 65 years of age or older). Yet persons in this age segment of the U.S. population, the age group most susceptible to cancer, do not receive a share of cancer control efforts commensurate with their vulnerability to malignant disease.1 Individuals in this age group have a risk of developing cancer eleven times greater than individuals younger than 65 years. The risk of cancer mortality for the 65+ group is 15 times greater than those younger than 65.2 Data on incidence rates (i.e., the number of newly diagnosed cases occurring per 100,000 persons in a given time frame), reported by the National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) Program for 1988-92 reveal that the rate for persons 65+ is 2214.9/100,000 population in contrast to 201.5/100,000 population.2 Mortality rates for this same period are 1080.3/100,000 for persons 65+, as compared to 73.3/100,000 for persons younger than 65. These overall rates translate into proportions for the 65+ that show 60% of all incident cancers and 68% of cancer deaths occur in this older age group.2

The tumors with overall higher incidence and mortality rates disproportionately affect the older population. Ten tumors are selected to demonstrate this assertion—cancers of the colon, rectum, lung, pancreas, stomach, urinary bladder, prostate, breast, and ovary, and non-Hodgkin’s lymphoma. This particular group of malignancies account for a vast share of the total cases (71% [n = 366,627)] registered for all 66 cancer sites in the NCI SEER database during 1988-1992 (n = 518,764). The age group 65+ accounts for 66% of these common tumors (n = 241,299).3

Table 1 shows a percentage distribution of the incidence of these tumors that affected the 65+ group between 1988 and 1992.

Table 1

Percentage of Cases for 10 Selected Tumors Occurring in the 65+ Age Group

Tumor Incidence (%)

Colon 73.8

Rectum 66.0

Lung 62.7

Pancreas 71.8

Stomach 68.5

Bladder 69.9

Non-Hodgkin’s Lymphoma 51.2

Prostate 80.9

Breast 48.2

Two-thirds to three-fourths of cancers of the colon, rectum, stomach, pancreas, and urinary bladder occurred in people age 65 or older. These cancers are common in men and women. About 63% of lung cancers and more than 50% of non-Hodgkin’s lymphomas occur in older men and women. A very high proportion of prostate cancer incidence (81%) occurs in men 65 years and older. Two prominent female cancers, often thought to be very common in premenopausal women (i.e., women 50 years and younger), are breast cancer and ovarian cancer. However 48% of all breast cancers and 46% of all ovarian cancers occur in the older subset of postmenopausal women (65+). Thus, the 65+ population bears the greatest burden of cancer incidence.

Clinical Challenge

The imbalance in the percentage of cancers striking those in the older age strata of the population creates a special challenge for oncologists in many ways, though only the more obvious problems can be highlighted here.

First, assuming that many persons in the 65+ age group already have existing age-related chronic conditions, the needs of older cancer patients are likely to be associated with concomitant health problems. These may be major chronic conditions that already require serious medical attention (e.g., heart disease, chronic obstructive pulmonary diseases, diabetes, hypertension, etc.). Little is known, however, about the effect that the combination of a malignancy and existing health problems have on therapeutic options and cancer care for the elderly. Moreover, it is not even known what these conditions are and how many are present in newly diagnosed older-aged cancer patients. There are some studies that are beginning to address this knowledge gap. Documentation of the prevalence of comorbidity in older-aged cancer patients is underway in analyses being conducted on data from the National Institute on Aging (NIA) and the NCI Collaborative SEER Study.4 In the NIA/NCI SEER Study, arthritis, heart-related problems, hypertension, and gastrointestinal problems emerge as the four leading comorbid conditions present as a current medical problem or history in the age groups of 65-74 years and 75 years and older. Balancing treatment and care priorities in this context can be a clinical dilemma because of the intersection of pathophysiologic processes and the potential for adverse interactions among the multiple drugs required to treat them.

Second, from a demographic perspective, as the older age segment of the U.S. population continues to expand in absolute numbers as well as the proportion represented in the total population, there will be many more older cancer patients if incidence rates remain the same and population projections are fulfilled. The 65+ age group is 10 times larger than it was in 1900.5 Moreover, this age group is expected to double in number from 1990 to 2030, the year in which the youngest of the "baby boom" generation born between 1946-1964 turns 65. Data from the U.S. Bureau of the Census show that older Americans currently make up about 13% of our present population, 31,079 million. By 2030, 20% of the population will be 65 years and older, representing 69,839 million individuals.5

A third challenge involves the deficiencies and weaknesses in the nation’s health care system for providing health care and supportive services (e.g., availability of caregivers) and the upward spiraling of health care costs. A recent study using data from the 1987 National Medical Care Expenditure Survey and the National Health Interview Survey suggests that the total prevalence of chronic conditions may have been underestimated and costs (affecting persons of all ages, not only the elderly) are extremely high because of the greater health care needs of people with chronic medical conditions. The authors state "Our health care system remains firmly rooted in episodic and acute care, but it is unlikely to continue this way in the next century.6" It is important, also, to consider the various adverse social and economic aspects of an older cancer patient’s life situation as it is connected with the medical symptoms and course of illness. The 65+ group, more than any other age group, have such age-related crises as reduced income, loss of loved ones and family support, and changing living arrangements. These are all interconnected with the diagnosis of cancer in the presence of other chronic health problems.7

Fourth, the lack of cancer treatment guidelines pertinent to older patients poses a real problem for practitioners. Older cancer patients with competing concurrent health conditions and poor physical functioning usually do not participate in cancer clinical trials. There is not a large body of evidence to guide treatment of cancer in the elderly, though there is more interest and activity in research on aging and cancer proposed within the first half of the 1990s.1,7-9

Pervasive Need for Aging/Cancer Research Interface

The persistent theme of this article is that we must produce reliable and pertinent information to meet the needs of the elderly, for they are the individuals most highly prone to develop cancer. An integration of aging and cancer research is urgently needed to address crucial questions. We must apply what is known in oncology and geriatric medicine to the issues and concerns regarding cancer in the 65+ age group. The unique features of aging and/or symptoms of illness in old age that influence the early detection, diagnosis, treatment, and care of older-aged patients with cancer must be ascertained. Information is needed on how treatment differences or modifications are made because of old age; assessment of the effectiveness of different treatments relative to the stage of disease and characteristics of old age (e.g., poor DNA repair mechanisms, poor wound healing, functional loss, greater susceptibility to toxicity of treatment, hypercoagulable states). Finally, data on the evaluation of tolerance and response to standard or experimental adjuvant therapy regimens or multimodality cancer treatment interventions (controlling for physiologic parameters and other factors) are needed for older patients with all types of malignancies.

As a new area of emphasis for the NIA Geriatrics Program, we have activated extramural research initiatives to take advantage of recently acquired knowledge and expertise in medical oncology by focusing on the expanding information base for two gender-specific malignancies—breast and prostate cancers. We hope to translate and apply existing knowledge as well as develop information pertinent to the 65+ age group at high risk for these tumors.

In 1996, the NIA initiated two Program Announcements (PA) to encourage the extramural research community in medical oncology, geriatric medicine, and relevant disciplines and professions to broaden the scope of aging and cancer research to include a focus on the 65+ age group. Both PAs are cosponsored with the NCI. We were joined by the National Institute on Nursing Research and the National Institute on Mental Health for the research solicitation entitled "Aging Women and Breast Cancer." The National Institute of Environmental Health Sciences is a cosponsor with the NIA and NCI for the prostate cancer research solicitation, "Aging, Race, and Ethnicity in Prostate Cancer."

Program Announcements

PA-96-034, NIH GUIDE, Volume 25, Number 12, April 19, 1996—Aging Women and Breast Cancer. Emphasis on age for research on breast cancer is essential because of the magnitude of the problem of this tumor for older women. Age-adjusted rates reported by the NCI Surveillance, Epidemiology, and End Results (SEER) Program reveal that women 65 years or older have an incidence rate of 444.7/100,000 population as compared to 72.8/100,000 for women under 65 years of age. The peak breast cancer incidence rate of 483.9/100,000 is in the age group 75-79 years. The breast cancer mortality rate for women under 65 years of age is 16.6/100,000 as compared to the rate for women 65 years and older, which is 125.8/100,000. The peak mortality rate, 191.0/100,000, occurs in the age group 85 years and older.2

The focus on research relates to areas identified earlier as well as those of cellular senescence, aging, and cancer; age-related biological factors that affect the initiation, promotion, or treatment of cancer; and age-related differences in drug sensitivity and metabolism. Clinical research questions include ways to enhance early detection of breast cancer and testing new interventions or treatment strategies in the presence of an older patient’s preexisting comorbid conditions (e.g., hypertension, heart disease, diabetes, etc.). It is extremely important to reduce age-associated disease complications in early detection and diagnosis of breast cancer (e.g., masking of signs and symptoms) and to lessen age-associated potential that would result in reduction in treatment efficacy.

PA-97-019, NIH GUIDE, Volume 25, Number 44, December 20, 1996—Aging, Race, and Ethnicity in Prostate Cancer. Special consideration for prostate cancer research on behalf of older men is essential because this tumor has the highest incidence of any malignancy affecting men in the United States. In 1996, 317,000 new prostate cancer cases were estimated by the American Cancer Society. Further, prostate cancer is especially serious for black Americans who experience the highest incidence of this malignancy in the world.10

The NIA/NCI prostate cancer initiative features the contrasts and magnitude of the problem for older white and black Americans. Using age 65 years as a breakpoint, age-adjusted rates per 100,000 population for 1988-1992, show that white men under 65 years have a rate of 32.0 as compared to 48.3 for blacks. For men 65 years and older, the rates are 1120.3 for whites as compared to 1458.9 for blacks. Age-adjusted mortality rates are more than twice as high for blacks as compared to whites for both younger and older age groups. For men under 65 years, the mortality rate for whites is 2.6 as compared to 7.3 for blacks. For men 65 years and older, the rates are 219.7 for whites as compared to 475.6 for blacks.2

The prostate cancer research solicitation encourages research that includes studies on factors that affect the rate of increased risk with age for prostate cancer, and/or the rate of development and progression of premalignant changes in prostate tissue, as well as their interaction with familial factors, race, and/or ethnicity; epidemiologic studies of age-related familial, genetic, and environmental factors that may affect the age of onset, rate of progression, and duration of survival for prostate cancer; and interactions of aging and age with prostate cancer risk factors (e.g., relative prominence of various risk factors for onset of prostate cancer at different ages). Other issues include the extent and mechanism by which age-related prostate growth leads to increased incidence of prostate cancer and the protective factors that mitigate against prostate cancer (i.e., factors that allow aging without development of premalignant changes) or metastatic potential of various precursor lesions for prostate cancer in aging men.

The clinical concentration in the prostate cancer program announcement is concerned with the determinants of age- and race-associated differences in prostate cancer treatment efficacy for such outcomes as survival, treatment, complications, side effects of treatment, and functional status and the special features of aging and/or symptoms of illness in old age that influence the treatment and care of older-aged prostate cancer patients.

In both breast and prostate cancer research initiatives, the emphasis is placed on improving methods to identify high-risk older women and older men through development of new techniques to distinguish premalignant changes from nonmalignant age-associated changes in breast and prostate tissues. The full text for these two program announcements may be obtained from the NIH Guide to Grants and Contracts Page at the NIH Website (http://www.nih.gov).

Final Comment on Cancer in the Elderly

Cancer refers to a hundred or more different diseases, involves many organs and systems of the body. Our focus here has been on the major tumors. Moreover, as we refer to "the elderly", "the aged", "older persons", and use age 65+ in this article, these terms are a component of an arbitrary convention, a customary cut-off point for selected medical, social, and economic issues. Certainly, age may be defined in many ways other than chronological (e.g., in physiological and functional terms). The extreme diversity and heterogeneity within this age category is acknowledged. (Dr Yancik works for the National Institute on Aging, Geriatrics Program.)

References

1. Yancik R, Ries LG. Cancer in older persons: Magnitude of the problem—How do we apply what we know? Cancer 1994 (Suppl);74:1995-2003.

2. Kosary CL, et al. eds. SEER cancer statistics review. 1973-92: Tables and graphs, National Cancer Institute. NIH Publication No. 96-2789. Bethesda: National Institutes of Health; 1995.

3. NCI SEER Program, Unpublished data, 1988-1992.

4. The National Institute on Aging and the National Cancer Institute Seer Collaborative Study on Comorbidity and Early Diagnosis of Cancer in the Elderly is in progress as an assessment of concurrent diseases present upon diagnosis of selected tumors.

5. Taeuber CM. Sixty-five plus in America. Current Population Reports P23-178RV. U.S. Bureau of the Census. 1993.

6. Hoffman C, et al. Persons with chronic conditions. JAMA 1996;276:1473-1479.

7. Trimble EL, et al. Representation of older patients in cancer treatment trials. Cancer 1994;74:2208-2214.

8. Monfardini S, Yancik R. Cancer in the elderly: meeting the challenge of an aging population. JNCI 1993; 85:532-538.

9. Fentiman IS. Are the elderly receiving appropriate treatment for cancer? Annals Oncol 1996;7:657-658.

10. Cancer Facts and Figures, 1996. Atlanta: American Cancer Society; 1996