Mammography in the Geriatric Population

ABSTRACT & COMMENTARY

Synopsis: This report describes a retrospective cohort study of a representative sample of women in the United States age 75 years and older who participated in the Medicare Current Beneficiary Survey. Overall, 26.7% of the women had mammography in the two-year period. This report should serve as a spring board to further investigation into the factors that influence mammography rates in geriatric populations.

Source: Blustein J, Weiss LJ. J Am Geriatr Soc 1998; 46:941-946.

Mammographic screening in the eldery age groups is of unproven benefit and recommendations vary for its use. The American Medical Association and the American Cancer Society recommend annual screening for all women over the age of 50,1,2 whereas the U.S. Preventive Services Task Force cuts off screening at the age of 69.3 Perhaps most relevant is that the Medicare program reimburses for biennial screening without an upper age limit.4 Experts agree that this is an understudied issue, especially in light of the fact that 50% of all breast cancer in the United States occurs in women older than 70 years.5

The current study was designed to address the extent to which health, functioning, and age influence mammography use in those older than 75. A retrospective cohort study of a representative sample of women in the United States age 75 years and older (n = 2352) were interviewed to gain information about general health, level of functioning, medical history, age, and various sociodemographic characteristics. The findings were linked with subjects' Medicare bills for 1991 and 1992 as a measure of mammography use.

During this two-year period, 26.7% of this group of older women had mammograms. Health factors did influence the rate of mammography. For example, those who rated their health as good or excellent were twice as likely to have had mammography as those who rated their health as poor. Similarly, those without limitations on their activities of daily living (ADLs) were more likely to be screened. Such was also the case for those without stroke, hip fracture, or dementia. However, age alone was also a risk factor for not being screened. When the populations were adjusted for these and other health factors (such as socioeconomic status, education, and insurance), it became apparent that age alone accounted for a steep drop off in use of mammography screening. For example, 34.1% of those age 75-79 were screened, compared to 26.4% of those 80-84, and 11.8% of those 85 and older.

Thus, it is apparent that in one segment of our population mammography use is low. This may reflect patients' informed decisions, physicians' judgments, patients' and/or physicians' biases, or other factors, but as the population ages, more data will be needed about the value of breast cancer screening in the elderly.

COMMENTARY

This report clearly describes a common but unfounded pattern of diminished enthusiasm for preventive measures among individuals of advanced age. Of course, some of this may reflect ambivalence among experts in the field about the use of mammography and its cost effectiveness in those older than 70 years. Clearly, the question needs to be studied more thoroughly. However, short of definitive results from well-designed clinical investigation, informed and non-biased decisions on an individual basis will need to suffice.

To the extent that physicians are responsible for reduced screening in the elderly, decisions not to screen should be based upon an assessment that discovering an early breast cancer would have minimal impact on treatment decision and the length and quality of the patient's remaining life. Thus, in 85-year old women with one or more advanced diseases and a limited life expectancy, mammography might not seem rational. On the other hand, women of that age without a known major illness may expect, on average, to live a decade or more. In these individuals, resecting a small cancer is likely to allow the maintenance of that life expectancy and certainly will add to the quality of that remaining time.

When deciding about mammography physicians need to remember: 1) Mammography is technically more precise in older women, primarily because of the presence of more fatty tissue and less glandular tissue.6 2) Older women are much more likely to have positive mammograms because tumor prevalence increases with each advancing decade. The median age for breast cancer in the United States is 70.4 3) Tumor progression is probably slower in older women. Thus, early detection may be more likely to result in a surgically curable lesion. 4) Despite the presence of more indolent disease, older women are more likely to present with locally advanced disease.7 This suggests that screening (including self and clinical exams and mammography) is less frequently undertaken in older women. 5) Elective surgery is well tolerated, with modest, if any increase, in morbidity or mortality, when compared to younger patients.8

Factors relating to the failure to obtain mammography in older women are nicely described in this paper. Women with functional impairment, prior stroke, hip fracture, or dementia were less likely to be screened. However, other illnesses were not associated with less mammography. These included hypertension, diabetes, and prior myocardial infarction. Yet, controlling for all these various functional and health characteristics, Blustein and Weiss found a fairly dramatic drop off in screening in the oldest age groups. This is an important finding and warrants further investigation. To the extent that it reflects a lack of understanding or initiative by health providers, efforts at continuing education will be warranted.

References

    1. American Medical Association, Council on Scientific Affairs. JAMA 1989;261:2535-2542.

    2. American Cancer Society Mammography Guidelines. CA Cancer J Clin 1983;33:255-259.

    3. US Preventive Services Task Force. Guide to Clinical Preventive Services, 2nd Ed. Alexandria, VA: International Medical Publishing, 1996.

    4. Nattinger AB, et al. Arch Int Med 1992;152:922-925.

    5. Ries LAG, et al. SEER cancer statistics review, 1973-1993: Tables and graphs. In NIH. Bethesda, MD: US PHS, 1996.

    6. Faulk RM, et al. Radiology 1995;194:193-196.

    7. Yancik R, et al. Cancer 1989;63:973-981.

    8. Hosking MP, et al. JAMA 1989;261:1909-1915.