One of the fundamental goals of primary care medicine is the prevention or early detection of disease through screening. Screening can lead to interventions that may decrease morbidity and mortality, but it can also lead to increased morbidity and mortality if performed inappropriately. Evidence-based and consensus guidelines have been released by various government and specialty organizations regarding cancer screening. These guidelines generally recommend at what age to initiate screening and how often to screen, but do not always specify when screening should stop. The following is a review of guidelines and data regarding the cessation of cancer screening in older patients, and suggestions for how to incorporate these guidelines into daily practice.
|Clinical recommendation||Evidence rating||References|
|Cervical cancer screening may be stopped at 65 years of age, if the patient has a history of normal screening.||C||10–13, 21, 22|
|Breast cancer screening may be stopped at approximately 75 to 80 years of age for a woman at average risk and with average overall health status.||B||14–16, 26, 27|
|Colon cancer screening may be stopped at approximately 75 years of age for men and 80 years of age for women, with life expectancy and comorbidities considered in the decision.||B||7, 17, 28|
|Prostate cancer screening, if conducted at all, may be stopped at approximately 75 years of age, or when life expectancy is less than 10 years.||C||18–20, 29, 30|
|Age (years)||Total (years)||Men (years)||Women (years)|
|Alzheimer disease||Not specified||Men: 4.2 years|
|Women: 5.7 years|
|Hip fracture||80 years||5.4 years|
|Congestive heart failure||> 75 years||Men: 3.9 years|
|Women: 4.5 years|
|Myocardial infarction||Not specified||11.3 years|
|Type of cancer||Age (years)|
A Framework for Decision Making
There are currently more than 30 million Americans older than 65 years. this number is expected to increase to more than 70 million by the year 2030.1 Life expectancy continues to rise, with an average life expectancy at birth of 75 years for men and 80 years for women (Table 1).2 Life expectancies of patients diagnosed with selected comorbid diseases are shown in Table 2,3–6 and patients' risk of dying of specific cancers is shown in Table 3.7
A framework for decision making about cancer screening should be built on available evidence-based medicine guidelines, patients' risk of dying (estimated by life expectancy and comorbidities), the benefits and harms of screening, and patients' preferences and values. Patients may vary greatly in their overall health expectations and preferences of what screening they want to have performed.7,8 The risks of screening include complications from additional testing or from treatment of clinically insignificant cancers, as well as psychological complications from the distress of screening and its possible implications.
There are a few key elements that comprise an effective medical screening test: the target disease should be common and should cause significant mortality and morbidity; the test should be accurate as well as reasonably tolerable; a positive result should allow for beneficial intervention during the asymptomatic phase of the disease; and the test and the cure should be cost-effective.9 The relative importance of these key points shifts when comparing patients of different ages. For example, cancer is more common in older patients than in younger ones, so screening may be more likely to detect true malignancies in older patients. Additionally, screening tolerability may decrease with age, such as with Papanicolaou (Pap) smears, which may be significantly less comfortable in older patients because of vaginal atrophy and osteoarthritis of the hips. Finally, the cost effectiveness of the screening and the ability to benefit from early interventions can change based on a patient's age.
Cervical Cancer Screening
The mainstay of cervical cancer screening is the Pap smear. Table 410–20 lists the guidelines for cervical cancer screening in older persons from the American Academy of Family Physicians (AAFP), the U.S. Preventive Services Task Force (USPSTF), the American College of Obstetricians and Gynecologists (ACOG), the American Cancer Society (ACS), and the American Geriatrics Society (AGS). The guidelines range from specific recommendations to stop screening at either 65 or 70 years of age to suggested decision-making based on the patient's age and risk factors. However, there is consensus from each organization that Pap smears may be stopped following a hysterectomy for benign indications with removal of all cervical tissue.
|Organization||Recommended age of cessation|
|Cervical cancer screening|
|AAFP/USPSTF||65 years of age “if they have had adequate recent screening with normal Pap smears and are not otherwise at high risk”10|
|ACOG||Age determined “on an individual basis … based on such factors as [the patient's] medical history and the physician's ability to monitor the patient in the future”11|
|ACS||70 years of age and “three or more normal Pap tests in a row and no abnormal Pap test results in the past 10 years”12|
|AGS||70 years of age; “There is little evidence for or against screening women [beyond age 70] who have been regularly screened in previous years”13|
|Breast cancer screening|
|ACS||“The decision to stop screening should be individualized on the basis of the potential benefits and risks of screening in the context of overall health status and longevity”14|
|AGS||“[Screening may continue in women with] an estimated life expectancy of four or more years”15|
|USPSTF||“Women with comorbid conditions that limit their life expectancy are unlikely to benefit from screening”16|
|Colon cancer screening|
|USPSTF||Recommends against routine screening in adults 76 to 85 years of age; recommends against screening in adults older than 85 years17|
|Prostate cancer screening|
|AAFP/USPSTF||Recommends against screening for prostate cancer in men 75 years and older18|
|ACS/AUA||Screening for prostate cancer should be offered annually beginning at 50 years of age to men who have a life expectancy of at least 10 years19,20|
Another consistent element across all four guidelines is the requirement that patients have a history of normal results before screenings are stopped. This is based on data showing that women with prior normal screens have a lower risk of future high-grade lesions and cancer. A systematic review of studies from 1995 to 2001 showed that fewer than one in 1,000 women older than 60 years with a normal baseline Pap smear developed high-grade cervical lesions or cervical cancer; however, this risk nearly doubled in women with no prior baseline Pap smears.21 A retrospective analysis of more than 600,000 women screened over six months showed that more than 80 percent of women with a high-grade lesion or cancer had either abnormal Pap smears or no Pap smears in the past.22
Data from one California-based study suggest that the age-based recommendations to stop cervical cancer screening are not being followed universally.23 The study, which involved a health interview survey of more than 4,500 women older than 70 years, found that the percentage of women being screened did not differ significantly between the healthiest population (i.e., longest life expectancy) and the least healthy (i.e., shortest life expectancy), regardless of age. More than 50 percent of women older than 80 years in the worst health quartile reported that they were still receiving Pap smears.
Breast Cancer Screening
Breast cancer screening modalities include mammography, clinical breast examination, and breast self-examination. This review focuses on mammography as a screening tool, because it is the best-validated breast cancer screening. The guidelines regarding the cessation of mammography list age, life expectancy, and health status as key factors (Table 410–20). The AAFP does not comment on the use of mammography for women older than 69 years, and the ACOG has not issued recommendations on the cessation of mammography.
The AGS includes a four-year life expectancy as a requirement for breast cancer screening. This stems from two large longitudinal studies of women 40 to 74 years of age who were either screened with mammography or not screened. The studies show that screening decreased mortality, though the beneficial effect appeared with a lag time of four to five years after screening.24,25
Various studies have assessed the benefits of mammography in women of different ages. A case-control study of women receiving mammography showed decreased mortality in women younger than 75 years, but no survival benefit in women older than 75 years.26 A 2003 cost analysis from the USPSTF showed that mammography was cost-effective for women up to 80 years of age, but only in healthy patients with the greatest life expectancy.27
Another study also stressed the importance of life expectancy on the effectiveness of mammography in older women. In 75-year-old women, the calculated number needed to screen (NNS) to prevent one breast-cancer–specific death was 176 in a group with a 17-year life expectancy, compared with 1,361 in those whose life expectancy was only seven years.7 This supports the theory that women with longer life expectancies are more likely to benefit from screening with mammography. Therefore, a reasonable recommendation based on these guidelines is to continue mammography until 75 or 80 years of age in healthy women, but to consider earlier cessation in those with significant comorbidities who have a remaining life expectancy of five years or less.
Colon Cancer Screening
Colon cancer screening modalities include fecal occult blood test (FOBT), barium enema, sigmoidoscopy, and colonoscopy. The USPSTF recommends against routine screening in adults 76 to 85 years of age, although there may be considerations that support screening in individual patients.17 The USPSTF also recommends against screening in adults older than 85 years.17 Recommendations from research studies have suggested that discontinuation of colon cancer screening should be based on age, life expectancy, and comorbidities.
One retrospective study compared life expectancy after diagnosis of stage I colon cancer at 67 years of age across a spectrum of health status to better define the benefits of early detection of cancer through screening.28 Life expectancy of otherwise healthy patients diagnosed with stage I disease was not different from persons without colon cancer. However, in patients with one or more chronic diseases, life expectancy after diagnosis was decreased compared with those without colon cancer, suggesting that early diagnosis through screening is more beneficial in patients with fewer comorbidities.
Another study assessed the NNS to prevent one colon cancer death through screening with FOBT in patients with different life expectancies.7 While the NNS for 70-year-old patients with 18-year life expectancies was calculated at 177, this number increased more than tenfold to an NNS of 1,877 in 70-year-old patients with a 6.7-year life expectancy. These data again suggest that older patients with the longest life expectancies and the fewest comorbid problems are more likely to benefit from colon cancer screening. With a suggested screening interval of 10 years for colonoscopy, it is reasonable to discuss discontinuing screening when a patient's life expectancy approaches 10 years. This corresponds to approximately 75 years of age for men and 80 years of age for women (Table 12).
Prostate Cancer Screening
Prostate cancer is fundamentally different from the three cancers discussed previously. With subclinical prostate cancer being detected at autopsy in more than 80 percent of men older than 70 years, it is determined that older men typically die with prostate cancer but not from it.29 Prostate cancer screening is controversial, because most men, if screened long enough, will test positive. There is continuing debate whether screening increases or decreases morbidity and mortality.30 Prostate specific antigen (PSA) testing and digital rectal examination are typically used in combination for screening. The AAFP and the USPSTF state that there is insufficient evidence to assess the balance of benefits and harms of screening for prostate cancer in men younger than 75 years.18 Additionally, the AAFP and USPSTF recommend against prostate cancer screening in men 75 years of age and older (Table 410–20).18 The ACS and the American Urological Association state that screening may be stopped in men with a life expectancy of less than 10 years,19,20 which corresponds to 75 years of age for an average man (Table 12).
Studies evaluating the mortality benefit of prostate cancer treatment have also yielded varying results.30–32 Despite conflicting evidence regarding the benefit of screening and treatment, one recent cohort study showed that more than 30 percent of men older than 85 years were still being screened for prostate cancer.33 In an attempt to better define higher risk elderly patients for screening, one study attempted to stratify prostate cancer risk based on PSA values found at 65 years of age.34 This study, from the Baltimore Longitudinal Study of Aging, showed that 94 percent of men who had a PSA of less than 1.0 at 65 years of age, and 100 percent of men with a PSA of less than 0.5 at 65 years of age remained cancer free (based on PSA values) at 10-year follow-up.34 This suggests that fewer men might be screened at older ages if men with low PSA values at 65 years of age were excluded from future screening.
Incorporation into Daily Practice
These data are provided as guides for physicians' decision making. The discussion with older patients and their families regarding screening can be even more complicated than the interpretation of the data and guidelines. It is imperative to carefully explain that cessation of screening is typically done to prevent harm, and not simply to ignore problems. While some patients may respond with relief at the thought of not undergoing further testing, others may feel discriminated against because of perceived ageism from their physician and the medical community. It is essential that a careful two-way dialogue, based on evidence-based guidelines and individual patient preferences, guide the decision to continue or to stop cancer screening.