Breast Cancer Screening: At What Age to Stop?

ABSTRACT: Some women 75 and older who are in good health and have excellent functional status may benefit from mammography screening, while others who are in poor health and have short life expectancies probably do not. The most significant risk of screening the oldest-old women is the detection of tumors that may not become clinically important during a patient's lifetime. The American Geriatrics Society encourages screening mammography for women younger than 85 who have at least 5 years' life expectancy and for healthy women 85 and older who have excellent functional status or who feel strongly about the benefits of screening. Several tools are available to help you target screening to older women with longer life expectancies. When you discuss stopping screening with older women who have shorter life expectancies, it is important to address the issues that make women want to continue screening, including habit and the need for reassurance.

Key words: breast cancer, mammography, screening, elderly

As more and more adults are leading healthy and independent lives well into their 80s and 90s, clinicians are increasingly faced with the difficult decision of whether to screen these patients for cancer. Guidelines from the US Preventive Services Task Force (USPSTF) now provide age cut-offs at which to stop screening older adults for prostate and colon cancers.^1,2 The USPSTF does not provide an age cut-off at which to stop screening older women with mammography; however, the USPSTF recently concluded that the evidence is insufficient to recommend for or against breast cancer screening for women 75 years and older and further recommends that these women understand the uncertainty of the balance of benefits and harms of mammography before undergoing screening.³

Although experts recommend stopping mammography screening among older women with less than 5 to 10 years' life expectancy,^4,5 I found that 39% of women 80 and older with probable life expectancies of less than 5 years were screened with mammography.⁶ This may be partly attributable to clinicians' discomfort about discussing with older women the decision to stop screening, difficulty in determining patient life expectancy, and uncertainty about guidelines.⁷

One of the reasons that guidelines for breast cancer screening among older women are vague is that none of the 8 randomized controlled trials that evaluated mammography included women 75 and older. Observational studies demonstrate a possible decrease in breast cancer mortality among healthy women 80 and older who are regularly screened with mammography^8-10; however, these studies are limited by lead time, length time, and selection bias.

While some experts generally encourage screening elderly women, others warn that screening may result in the detection of tumors that would not have become clinically important if they had not been found with mammography (overdiagnosis).⁴ In these cases, oldest-old women are exposed to the burdens of treatment and the anxiety of living with cancer without the benefit of improved quality or quantity of life.⁴

In this article, I discuss the benefits and risks of screening older women with mammography, and I review current policy and guidelines. I also provide tools to help you decide whether or not to screen an individual patient.

EVIDENCE SUGGESTING BENEFIT OF MAMMOGRAPHY SCREENING FOR THE OLDEST-OLD

While breast cancer–specific mortality rates have declined among women younger than 70 years, they have risen for women 80 years and older; these trends may be a result of underscreening and/or undertreatment of the oldest-old.^11-13 The oldest-old contribute the greatest burden to the number of total deaths from breast cancer each year (approximately 27% of breast cancer deaths in 2001 were among women 80 years and older, even though they had only 13% of incident breast cancers).¹²

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