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Cancer Screening in Older Adults JUDITH M. E. WALSH, MD, MPH, San Francisco, Califomia

Adults aged 65 and older represent an increasingly important segment of the US population. Cancer is an important cause of death in this group. Screening for cancer can significantly reduce cancer incidence and mortality. In this review I address screening for breast, cervical, prostate, lung, colorectal, and ovarian cancer in older Americans. Decisions about screening for cancer must consider the effects of screening, diagnostic evaluations, and treatments on the quality of life of each person. (Walsh JME: Cancer screening in older adults. West J Med 1992 May; 156:495-500) Screening for the early detection of cancer has been shown to decrease both cancer incidence and cancer mortality and is an important part of primary care practice."'2 Most studies on the efficacy of cancer screening, however, have been done in younger populations. In this review I focus on screening asymptomatic persons aged 65 and older for cancer. The cancers to be reviewed include breast, cervical, prostate, lung, colon, and ovarian.

Older adults have an increased incidence of chronic disease and disability. They are twice as likely to see a physician and three times as likely to be admitted to hospital.5 This increased likelihood of physician contact should present increased opportunities for cancer screening. Health maintenance visits, however, are usually not covered by Medicare A or B, although Medicare coverage has been extended to some screening tests, including mammography.

Demographics of Older Adults In 1987 people aged 65 and older comprised 12% of the United States population, for a total of 29 million. Because baby boomers are aging, between 1985 and 2030, the total population is expected to increase by 28%, while the proportion of those aged 65 and older is expected to increase by 128%. In addition, average life expectancy continues to increase. In 1986, the average life expectancy for a man was 71.3 years and for a woman, 78.3 years. The combination of this increasing life expectancy with the aging of the baby boomer cohort results in a great increase in the elderly population. Cancer is an important disease in older people. According to US all-cause mortality data, cancer is the leading cause of death in women aged 55 to 74, and it is the second leading cause of death in men aged 55 and older and in women aged 75 and older.3 Cancers with particularly high incidence in the population of older adults include lung, breast, colorectal, and prostate (Table 1).4

Cancer Screening in Older Patients Five characteristics of any disease determine its appropriateness for screening. * The disease should have a high prevalence among those screened. * It should have serious consequences. * It should have a detectable preclinical phase. * The disease should have a treatment that, when applied to presymptomatic disease, is more effective than if applied after symptoms develop. * The tests used should be simple, inexpensive, and acceptable with a high sensitivity and specificity.6', Screening for each type of cancer will be reviewed in the context of these five characteristics. In addition to disease characteristics, certain characteristics of older persons are also important for cancer screening. Cancer is common in these patients and usually presents at a late stage. Most clinical trials of cancer screening and treatment, however, have enrolled patients younger than 65. In fact, no prospective trials of any cancer screening examination have conclusively demonstrated efficacy in older persons. There are several important issues to consider when screening for cancer in the elderly. Are the treatments for cancer effective, feasible, and acceptable for patients in this age group? How often does screening lead to further evaluation, such as breast biopsy after mammography, that may prove unnecessary yet result in morbidity? Finally, does screening improve the quality of life and functional status of older adults?

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Screening for Breast Cancer Breast cancer has both a high prevalence and serious consequences. It is the most common cancer in women (except for skin) and the second most common cause of cancer death. It has a detectable preclinical phase (detection of a

From the General Internal Medicine Section, Department of Medicine, Veterans Affairs Medical Center, San Francisco, California. Reprint requests to Judith M. E. Walsh, MD, MPH, General Internal Medicine Section, Department of Medicine, Veterans Affairs Medical Center, 4150 Clement St, 11 lAl, San Francisco, CA 94121.

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mass by clinical examination or cancers detected and treated at

mammography), and breast earlier stages have a much better prognosis than those detected later. Finally, the screening tests for breast cancer have proven efficacy in reducing mortality. A family history of breast cancer in a premenopausal mother or sister is an important risk factor, although it is probably less important in postmenopausal women. The breast cancer risk is doubled if a mother or a sister has breast cancer and is tripled if both a mother and a sister have breast cancer. Other risk factors include early menarche, late menopause, fibrocystic disease (when accompanied by proliferative changes, papillomatosis, or atypical epithelial hyperplasia), and endometrial carcinoma.8 Of all newly diagnosed cases of breast cancer, 43% are in women aged 65 or older. The incidence of breast cancer increases progressively with age and almost triples between the ages of 40 and 84 (see Table 1). As the population of older women increases, there will be a large increase in the absolute number of cases of breast cancer. Most studies of breast cancer screening have not included patients older than 65. Studies that have included older women have shown varying effects of screening. The Health Insurance Plan of Greater New York (HIP) study is one of the landmark studies showing a reduction in breast cancer mortality with annual breast physical examination and mammographic screening. It was a randomized, controlled trial of women aged 40 to 64 observed prospectively for four years. In women aged 50 to 64, there was a 30% decrease in breast cancer mortality 16 years after screening.9 An analysis of breast cancer mortality distribution, by age, 18 years after trial entry showed that in the cohort of women aged 50 to 64 at entry, breast cancer mortality was significantly lower among those screened. There was a 16.7% reduction in breast cancer deaths among screened women aged 60 to 64 at follow-up 18 years after trial entry. ° In a Swedish randomized, controlled trial of women aged 40 to 74, annual mammography, but not physical examination, was studied. At seven-year follow-up, there was a 40% decrease in breast cancer mortality in those aged 50 to 74 at the time of study entry. At eight years' follow-up, breast cancer mortality was decreased by 24% in the screened group. I Although women older than 65 are included, a separate analysis for the older group is not possible. The ideal frequency for mammographic screening in older women depends on the size of the preclinical interval-

the period during which early disease is present but symptoms have not yet developed-and on the incidence and

aggressiveness of cancers that occur between screening examinations. There is some evidence to suggest that the preclinical interval is longer in women older than 50. A recent analysis of data from the Swedish two-county breast cancer screening trial demonstrated that among women older than 50, few interval cancers were seen in the two years after a screening mammogram, whereas in women aged 40 to 49, the rate of interval cancers in the first and second years following screening was significantly higher.'2

Screening for breast cancer includes both mammography and clinical breast examination. In both the HIP study and the Breast Cancer Detection Demonstration Project,'3 the screening procedures were clinical examination and mammography. There have been no trials to evaluate annual clinical examination only.'3 Eddy estimates that annual breast physical examinations for ten years can be expected to decrease the chance that a woman will die of breast cancer by about 15 to 40 per 10,000.14

Because the incidence of breast cancer increases with the absence of data for screening women older than 75 should not preclude screening. The recommendations of various expert organizations are listed in Table 2.ls5-20 According to a recent cost-effectiveness analysis, because the length of the preclinical interval may be increased in women older than 50, screening low- or average-risk women every two years retains a high proportion of the effectiveness of annual screening. 14 High-risk women should probably be screened annually. The upper age limit at which breast cancer screening has a significant effect in decreasing breast cancer mortality is not known. Decisions regarding continued screening after the age of 75 should be made by the woman and her physician, based on such factors as co-morbid conditions and associated life expectancy, feasibility and acceptability of surgical therapy, and quality of life. For example, a frail 75-year-old woman on home oxygen therapy for end-stage chronic obstructive pulmonary disease would probably benefit little from screening mammography. The early detection of breast cancer might increase her life expectancy but would not improve her quality of life. In addition, it is unlikely that this patient would be a surgical candidate. In contrast, the early detection of breast cancer in an active older woman with well-controlled hypertension would be more likely to improve the quality of her remaining years of life. age,

|TABLE 2.-Recommendations Regarding Breast Cancer Screening source Re.ommendation

American Cancer Society* ........... ............... National Cancer Institutet .......................... American College of Obstetricians and Gynecologistst .... American College of Physicians§ ........ ............. American Geriatrics Societyll ........................ American College of Radiology¶ ........ ............. US Preventive Services Task Force# ....... ............ 'From the American Cancer Societf.15 tFrom the National Cancer Institute.16 $From the American College of Obstetricians and Gynecologists.17 §From the American College of Physicians.18 IlFom the American Geriatrics Societya19

Annual- breast examination and mammogram for women older than 50 Annual breast examination and mammogram for women older than 50 Breast examination and mammogram at a frequency determined by the woman's physician Mammogram from age 50-59 on a "routine basis" and age 60 and older with a screening interval chosen by the physician and the patient Annual breast examination and mammogram every 1-2 years Annual clinical breast examination and mammogram in women older than 50 Annual clinical breast examination and mammography every 1-2 years (until age 75*) unless disease is detected ¶From the American College of Radiology.20 #From the US Preventive Services Task Force.1 Although the US Preventive Services Task Force recommends mammography annually or every 2 years until age 75, the upper limit at which breast cancer screening no longer has a significant effect in decreasing breast cancer mortality is unknown.

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Mammographic screening rates remain low in older women. Even though they have a higher incidence of breast cancer, they are screened less often than younger women.2 Furthermore, a recent community survey by Harris and colleagues showed that younger women were more worried than older women about breast cancer and assessed their risk as higher, attitudes that were generally associated with higher mammography rates.22 To increase mammographic screening in the older age group, patients and physicians must be

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that Papanicolaou smear screening of older low-income women (without a history of adequate screening) was cost effective. 26

The reliability of Papanicolaou smears in the elderly differs from that in other age groups. Without estrogen stimulation, atrophy and resulting inflammation can be confused with all degrees of dysplasia and even malignancy. Hence, there is a high incidence of false-positive smears in the elderly. Therefore, all abnormal smears should be repeated

educated.

after a brief course of estrogen.27

Screening for Cervical Cancer Worldwide, cervical cancer is the second leading cause of cancer death for women. In the United States, the incidence of cervical cancer is much lower (see Table 1). About 4,400 deaths from cervical cancer (compared with 46,000 from breast cancer) are expected to occur in 1992.3 Despite the low incidence, however, cervical cancer is appropriate for screening because of its long preclinical phase and the availability of a simple and inexpensive screening test. Finally, the early detection and treatment of the precursors of cervical neoplasia can substantially decrease the incidence of invasive

The preclinical phase of cervical cancer is long, and therefore even if the smear represents a true-positive result, the short delay entailed in repeating the examination after a course of estrogens should not substantially influence the course of disease. Because of vaginal and cervical stenosis, postmenopausal recession of the squamocolumnar junction, and the resulting difficulty in visualizing and sampling the transition zone, false-negative rates may be higher in the elderly as well. In a British study, 50 postmenopausal women were screened with cervical cytologic examinations and colposcopy. Four of the women had evidence of cervical intraepithelial neoplasia by colposcopy, although all had

cervical cancer. Risk factors for cervical cancer include sexual promiscuity and early age at first intercourse. In contrast to breast cancer, there is a low incidence of cervical cancer after age 65, but older women are less likely to have been previously screened. In fact, 15% of women aged 65 to 74 and 38% of women older than 75

have never had a Papanicolaou smear.23

Most studies showing that the incidence of invasive cervical cancer can be significantly decreased by cervical cancer screening have been done in younger populations. Because of the long preclinical interval, patients with two previous normal smears are at low risk for five years. A woman with a history of adequate screening gains little from screening after age 65. For example, an average-risk 65-year-old woman who has been previously adequately screened (every 3 years for at least 12 years) is screened every three years for an additional four examinations. This decreases her chance of death from cervical cancer by about 18 in 10,000, increases her life expectancy by about three days, and costs about $52,241 per year of life saved.24 This is in contrast to a calculated cost per year of life saved of $4,850 for biannual mammography in women aged 50 to 70.25 Hence, a key to determining the frequency of screening in an older population is the frequency of previous screening. Indigent women, who are at

increased risk, are less likely to have had previous adequate screening. A recent study done in an urban public hospital outpatient setting concluded

normal cervical smears.28

Many organizations have published recommendations for cervical cancer screening (Table 3). 1,29,30 Women with a history of previous adequate screening probably do not benefit from screening after age 65. Older women without a history of adequate screening should probably be screened every three to four years. It has been argued by some that the pelvic examination in older women, done in association with Papanicolaou smear screening, may result in the detection of other pelvic disease. There is no evidence that such detection leads to an improved clinical outcome.

Screening for Prostate Cancer The efficacy of screening for prostate cancer in men is not as well established as that of screening for breast and cervical cancer in women. With respect to prevalence, prostate cancer qualifies as a disease appropriate for screening. Prostate cancer is the most common cancer in American men and has the third highest cancer mortality rate.3 Of note are the particularly high incidence and mortality in African Americans,3' which persist even after adjusting for socioeconomic status.32 The incidence of prostate cancer among African Americans in Alameda County, California, is 100.2 per 100,000 compared with 0.8 cases per 100,000 in Shanghai, China.31 Furthermore, the age-adjusted prostate cancer death rate is 23.7 for all races compared with 46.8 for African

Americans.34 For most men, however, prostate

cancer

does not have

TABLE 3-Recommendations Regarding Cervical Cancer Screening Source

Recommendotion

Pap smear every 1-3 years in those without previous regular screening; asymptomatic women who have had several normal Pap smears may no longer need them after age 65. Consensust .Annual Pap smear for all who are or have been sexually active or who are age 18 or older; after 3 or more normal smears, they can be done less frequently if recommended by physician US Preventive Services Task Forcet .... ... Pap smear every 1-3 years, depending on risk factors; may stop at age 65 if several past smears were normal

American Geriatrics Society*.

'From the American Geriatrics SocietV.29

tFrom Fink.30 Consensus group includes American Cancer Society, National Cancer Institute, American Medical Association, American Nursing Association, American Association of Family Practitioners, American College of Obstetricians and Gynecologisits, and American Medical Women's Association. tFrom the US Preventive Services Task Foirce.

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serious consequences. A large number of cases of prostate cancer are found at autopsy or incidentally at transurethral resection of the prostate, but it is estimated that only 1 in 380 men with histologic evidence of prostate cancer die of it33 and that 9 of 10 prostate cancers remain clinically asymptomatic for decades.3" Although prostate cancer can metastasize, patients with metastatic prostate cancer are often asymptomatic. The disease should have a treatment that when applied to presymptomatic disease is more effective than if applied after symptoms develop. This may be true for prostate cancer but only if detection by screening is of stage A or B disease, as there is no effective curative treatment of stage C or D. The disease should have a detectable preclinical phase. The preclinical phase of prostate cancer is not well understood. Some prostate cancers are indolent, even when advanced, whereas some are aggressive, with early metastases before an abnormality is detectable on a rectal examination. Thus, even if asymptomatic prostate cancer is detected by digital rectal examination, this does not ensure that the cancer is at an earlier stage and hence more likely to be curable. In contrast, an asymptomatic breast cancer lesion detected by mammography is much more likely to be at an early stage and hence more amenable to treatment. The tests should be simple, inexpensive, and acceptable with a high sensitivity and specificity. At present there are three proposed screening tests for prostate cancer. Rectal examination is simple, cheap, and (probably) acceptable. Its sensitivity is estimated at about 70% in men with obstructive bladder symptoms but is only about 33% in asymptomatic persons.1 Transrectal ultrasonography is still considered experimental, and most studies have been done on those with suspected or confirmed prostate cancer. Tumor markers are in general not useful for screening. Prostatic acid phosphatase has a sensitivity of only about 20% to 45%. Prostate specific antigen is sensitive but not specific, as the levels are often also elevated in patients with benign prostatic

hypertrophy.35 To date, the results of prostate cancer screening have been disappointing. There is no evidence that disease detected through screening has a better prognosis. Although some studies have shown that screened populations are more likely to have stage A or B cancer, there is no evidence of improved mortality. The recommendations ofvarious expert groups are summarized in Table 4 1,16,36,37 The American Geriatric Society, American Cancer Society, and the National Cancer Institute recommend an annual rectal examination. The US Preventive Services Task Force states that there is insufficient evidence to recommend for or against screening for prostate cancer with an annual digital rectal examination. Because rectal examination is simple, inexpensive, and ac-

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ceptable (though not very sensitive), with few adverse effects, and while we await conclusive data about the efficacy of screening for prostate cancer, it is probably reasonable to do an annual rectal examination, especially in African-American men in whom the incidence and mortality are so high. Screening for Lung Cancer Lung cancer is the most common cause of cancer death in both men and women. Its incidence increases with age, reaching a peak annual incidence of 329.9 cases per 100,000 population in the 70- to 74-years age group (see Table 1). Although lung cancer is a prevalent disease with serious consequences, it does not fulfill other important screening criteria. To be appropriate for screening, a disease should have a detectable preclinical phase and the treatment of presymptomatic disease should be more effective than if applied after symptoms develop. Lung cancer detected and treated early, when the tumor is still localized, has a better prognosis than that detected at a later stage. In theory, then, the early detection of stage I tumors through screening could potentially prolong survival. But there is no evidence that screening leads to the detection of earlier stage disease, even in highrisk groups. In fact, in the Mayo Clinic (Rochester, Minn) Lung Project, the screening of male smokers every four months for six years with both chest roentgenograms and sputum cytologic examinations had no effect on the number of inoperable cases, the number of cases detected in the late stages, or the number of deaths from lung cancer.38 In addition, the current screening tests in use for lung cancer are neither sensitive nor specific. Chest x-ray films have an estimated false-positive rate offrom 0% to 10%. In an early Memorial Sloan-Kettering Cancer Center (New York) study, 10% of patients had abnormal chest roentgenograms that led to additional studies, such as bronchoscopy and fineneedle aspiration, to rule out lung cancer; 100 patients were evaluated per cancer found.39 There is good evidence that screening for the early detection of lung cancer has no effect on prognosis. Hence, many major organizations including the National Cancer Institute, the American Cancer Society, the United States Preventive Services Task Force, and the American College of Radiology agree that screening for the early detection of lung cancer is not justified. Rather than focusing on the treatment of lung cancer, clinicians' efforts should be directed at primary prevention-urging young people not to smoke and counseling older ones to stop smoking.

Screening for Colorectal Cancer Colorectal cancer is the second most common form of cancer; 156,000 new cases are estimated to occur in 1992.3

TABLE 4.-Recommendations Regarding Prostate Cancer Screening Source

Recommendation

American Cancer Society* ........ ...... Annual rectal examination National Cancer Institutet .............. Annual rectal examination American Medical Associationt .......... Transrectal ultrasound is investigational US Preventive Services Task Force§ ..... I.. nsufficient evidence to recommend for or against digital rectal examination; transrectal ultrasound and the use of tumor markers are not recommended From the American Cancer Societ.36 tFrom the Nationia Cancer Institute.16

From the American Medl Assodatn37 §From the US Preventiv Servkiesask Force.1

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Amerncan Cancer Society* .. National Cancer Institutet. |US Preventi Services Task Fc rce. From the American Cancer Society.40 nte 0 tFom, the4mtional anlu e.rfi

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lorec Cacer Srei Recommendation

Annual fecl occu bl tesi and ibl sgmidOscopyeve 3-5 yea apart for persons older than 50 Forthose at high risk.`ai`-contrst bariwn enema op 34 ears Annual fecal occlbloodtest and sigmoidosevery 3-5 years for '`case-finding" in asymptomatic persons insufficient evidee tome forornainstfaloctblood testing or sigmoidoscopy in asymptomatic individuals tS eing those at high risk may:be 'lnically prudent"

nthe"US Prevenive Servi Task Force.,

The incidence increases markedly with age, with the highest in persons aged 85 years and older. Important risk factors include inflammatory bowel disease, familial polyposis, a family history of colorectal cancer, and a personal history of breast, endometrial, or ovarian cancer. Approximately 58,300 deaths from colorectal cancer are expected to occur in 1992; substantial morbidity includes that related to colostomies, surgical therapy, radiation therapy, and chemotherapy. The treatment of early-stage disease is associated with a better prognosis than that of late-stage disease. Those who present with localized disease have a 74% ten-year survival rate, as compared with those who present with disseminated disease, who have a 5% ten-year survival rate. Colorectal cancer does have a preclinical phase-localized disease, such as polyp or adenoma-that can be detected by screening. The central issue in screening for colorectal cancer involves the screening tests (Table 5).1,16,40 Ideally a screening test should be simple, inexpensive, and acceptable. The screening tests available for colorectal cancer include digital rectal examination, fecal occult blood testing, and various types of sigmoidoscopy. The digital rectal examination is simple and acceptable, but only about 10% of colorectal cancers develop in the area that can be reached by an examining finger. Even if the digital rectal examination was extremely sensitive, 90% of cases of colorectal cancer would be missed using this method alone. Fecal occult blood testing is simple, cheap, and acceptable but has a high false-positive rate. It has been estimated that from 1% to 5% of unselected persons will have a positive fecal occult blood test.41 Of those with positive tests, 10% will have cancer and 20% to 30% will have adenomas. The positive predictive value of fecal occult blood testing for detecting cancer has been estimated at 5% to 10% .' Because about 20 ml of blood loss per day is needed for a persistently positive fecal occult blood test, there is a high false-negative rate as well. At present, clinical trials are evaluating the effectiveness of fecal occult blood testing in reducing mortality. Visual examination of the colon is the most effective way of detecting colon cancer. Sigmoidoscopy and colonoscopy have disadvantages, however, especially patient discomfort. In addition, because most colonic polyps will not develop into malignancy, there is a high false-positive rate. Perforation, although rare, is a serious iatrogenic complication. Finally, sigmoidoscopy is expensive, and the cost of doing annual sigmoidoscopies in all persons older than 50 would be prohibitive. At present, there is no direct evidence to support or refute screening for colorectal cancer, although indirect evidence suggests that screening with various tests can decrease the

disease-related incidence and mortality. Eddy presents a mathematical model of screening in which performing endoscopic evaluation or barium enemas at three- to five-year intervals preserves 90% of the effectiveness of annual examinations with much less inconvenience and cost.4" Because of the lack of definitive evidence, decisions about colorectal cancer screening should be made on an individual basis. There are several important factors to consider. First, what effect will a diagnosis of colon cancer have on a person's quality of life and functional status? The early diagnosis of colon cancer in an otherwise healthy 75-year-old man will probably have more effect on quality of life than a similar diagnosis in a person with end-stage congestive heart failure. Second, because any positive screening test will lead to further evaluation, such as flexible sigmoidoscopy after a positive fecal occult blood test, how acceptable is that for the patient? Third, if cancer is discovered, are the treatment options, such as surgery or chemotherapy, acceptable, feasible, and effective? Finally, the screening threshold should probably be lower for persons at higher risk for colorectal cancer, for example, those with a positive family history or a history of inflammatory bowel disease.

Screening for Ovarian Cancer About 21,000 new cases of ovarian cancer will be diagnosed in 1992.3 Although this incidence is substantially less than that for either breast or colon cancer, the incidence does increase with age. The disease is most common in women older than 60 years. Furthermore, it has the highest mortality of any of the gynecologic cancers. Risk factors include a family history of ovarian cancer and increased ovulatory activity, including nulliparity, late first pregnancy, and late menopause. About two thirds of women with ovarian cancer present with advanced disease. Survival is related to the stage at diagnosis and is specifically related to the size of the tumor after treatment. Various treatments appear to be more effective in reducing the size of residual tumor when ovarian cancer is detected early.42 This suggests that screening for the

detection of early disease would be efficacious. None of the available screening tests for ovarian cancer are appropriate for screening asymptomatic women. Although the pelvic examination is simple and inexpensive, ovarian cancer detected by this method is usually advanced. Malignant ovarian cells may be detected on a Papanicolaou smear, but the sensitivity is low. Cytologic examination of peritoneal lavage fluid obtained by culdocentesis is impractical for routine screening. The use of tumor markers, especially CA 125, is an area of present controversy. Although CA 125 levels are elevated in late-stage ovarian cancer, it is not known if they are suffi-

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ciently elevated in the early stages to be appropriate for screening. In addition, CA 125 levels are elevated in many persons with benign masses, as well as in those with nongynecologic cancers. Finally, there are minimal data regarding CA 125 screening in asymptomatic women.1 Another possible screening method for ovarian cancer is ultrasonography of the pelvis. Although ultrasound is sensitive and specific, because of the low prevalence of ovarian cancer in the general population, the positive predictive value is low. Jacobs estimated that in screening 100,000 women older than 45 years, 40 cases of ovarian cancer would be found, but there would be 5,398 false-positive results and an estimated 160 complications due to diagnostic laparoscopy.43 In summary then, given the limitations of available screening tests and the lack of direct evidence that screening for ovarian cancer improves the end result, there are no recommendations for routine screening for ovarian cancer in asymptomatic women. Although the United States Preventive Services Task Force recommends that it is "clinically prudent to examine the uterine adnexa when performing gynecologic examinations for other reasons,"' there are at present no data to support the use of other screening tests in asymptomatic persons. Summary and Conclusions Screening for certain types of cancer can decrease disease-related mortality. Although cancer is common in older persons, most studies of cancer screening have been done in younger populations. While awaiting the results of prospective trials of cancer screening in an older population, we can carefully extrapolate the results of cancer screening in younger populations. Available data suggest that screening for breast cancer and cervical cancer can substantially reduce disease-related mortality. Although conclusive data are lacking about the efficacy of screening for prostate cancer, because of its high incidence, it is probably reasonable to do an annual rectal examination, especially in high-risk persons such as AfricanAmerican men. Screening for lung cancer has been shown not to alter outcomes, and hence the routine screening of asymptomatic persons is not recommended. The early detection of colorectal cancer can improve the outcome, but the available screening tests have several limitations, including high false-positive rates, costs, and patient discomfort. Hence, decisions about colorectal cancer screening should be made on an individual basis. For ovarian cancer, there is no evidence that the detection of early disease by screening is associated with better results. When making any decision about cancer screening, physicians must weigh the risks and benefits for each patient. These risks and benefits include factors such as co-morbid diseases and associated life expectancy, the feasibility of surgical intervention, the acceptability of cancer treatments, and, most important for the elderly, the effects of screening and the resulting diagnostic evaluations and therapies on the quality of life. REFERENCES 1. United States Preventive Services Task Force: Guide to Clinical Preventive Services: An Assessment of the Effectiveness of 169 Interventions. Baltimore, Md, Williams & Wilkins, 1989 2. Hayward RSA, Steinberg EP, Ford DE, Roizen MF, Roach KW: Preventive care guidelines: 1991. Ann Intern Med 1991; 114:758-783 3. Boring CC, Squires TS, Tong T: Cancer statistics, 1991. CA 1992; 42:19-38 4. Sondik E (Ed): Annual Cancer Statistics Review. Washington, DC, Division of Cancer Prevention and Control, National Cancer Institute, 1988

5. Rice DP: Elderly demographics: Impact on health care. Hospitals 1988; 62:18 6. Frame PS, Carlson SJ: A critical review of periodic health screening using specific screening criteria-Part 4: Selected miscellaneous diseases. J Fai Pract 1975; 2:283-289 7. Hulka BS: Cancer screening: Degrees of proof and practical application. Cancer 1988; 62:1776-1780 8. Giuliano AE: Breast, chap 12, In Schroeder SA, Krupp MA, Tierney LM Jr, McPhee Si (Eds): Current Medical Diagnosis and Treatment, 30th Edition. East Norwalk, Conn, Appleton & Lange, 1991, pp 486-503 9. Shapiro 5, Venet W, Strax Venet L: Periodic Screening for Breast Cancer: The Health Insurance Plan Project and Its Sequelae. Baltimore, Md, Johns Hopkins University Press, 1988 10. Shapiro S: Determining the efficacy of breast cancer screening. Cancer 1989; 63:1873-1880 1 1. Tabir L, FagerbergCJ, Gad A, et al: Reduction in mortality from breast cancer after mass screening with mammography. Lancet 1985; 1:829-832 12. Tabar L, FagerbergCJ, Day NE, Holmberg L: What is the optimum interval between mammographic screening examinations? An analysis based on the latest J Cancer 1987; results of the Swedish two-county breast cancer screening trial. Br 55:547-551 13. Baker LH: Breast Cancer Detection Demonstration Project: Five-year sum1982; 32: 194-225 mary14.report. CA Eddy DM: Screening for breast cancer. Ann Intem Med 1989; 11 1:389-399 15. Summary of Current Guidelines for the Cancer-Related Checkup: Recommendations. New York, NY, American Cancer Society, 1988 16. Working Guidelines for Early Cancer Detection: Rationale and Supporting Evidence to Decrease Mortality. Bethesda, Md, National Cancer Institute, 1987 17. Standards for Obstetric-Gynecologic Services, 6th Edition. Washington, DC,

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American College of Obstetricians and Gynecologists, 1985 18. Screening for breast cancer, In Eddy DM (Ed): Common Screening Tests. Philadelphia, Pa, American College of Physicians, 1991 19. Screening for breast cancer in elderly women. JAm Geriatr Soc 1989; 37:883884 20. Policy Statement: Guidelines for Mammography. Reston,Va, American College of Radiology, 1982 21. Weinberger M, Saunders AF, Samsa GP, et al: Breast cancer screening in older women: Practices and barriers reported by primary care physicians. J Am Geriatr Soc 1991; 39:22-29 22. Harris RP, Fletcher SW, GonzalezJJ, et al: Mammography and age: Are we the wrong women? A community survey of women and physicians. Cancer targeting67:2010-2014 1991; 23. Robie PW: Cancer screening in the elderly.J Am Geriatr Soc 1989; 37:888893

24. Eddy DM: Screening for cervical cancer. Ann Intem Med 1990; 113:214-226 25. Van der Maas PJ, Koning HJ, van Ineveld BM, et al: The cost-effectiveness of breast cancer screening. Int J Cancer 1989; 43:1055-1060 26. MandelblattJS, Fahs MC: The cost-effectiveness of cervical cancer screening for low-income elderly women. JAMA 1988; 259:2409-2413 27. Weintraub NT, Violi E, Freedman ML: Cervical cancer screening in women and over.J Am Geriatr Soc 1987; 35:870-875 aged28.65 Roberts AD, Denholm RB, CordinerJW: Cervical intraepithelial neoplasia in women with negative cervical cytology. Br MedJ [Clin Res] 1985; postmenopausal 290:281 29. Screening for cervical carcinoma in elderly women.J Am Geriatr Soc 1989; 37: 885-887 30. Fink DJ: Change in American Cancer Society checkup guidelines for detection of cervical cancer. CA 1988; 38:127-128 31. Gittes RF: Carcinoma of the prostate. N Engl J Med 1991; 324:236-245 32. McWhorter WP, Schatzkin AG, HormJW, Brown CC: Contribution of socioeconomic status to black/white differences in cancer incidence. Cancer 1989; 63:982987 33. Chodak GW, Keller P, Schoenberg H: Routine screening for prostate cancer using the digital rectal examination. Prog Clin Biol Res 1988; 269:87-98 Americans. 34. Boring CC, Squires TS, Heath CW: Cancer statistics for African CA 1992; 42:7-17 35. Stamey TA, Yang N, Hay AR, McNeal JE, Freiha FS, Redwine E: Prostateantigen as a serum marker for adenocarcinoma of the prostate. N EnglJ Med specific 1987; 317:909-916 36. American Cancer Society: Guidelines for the cancer-related checkup: Recommendations and rationale. CA 1980; 30:193-240

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This article is one of a series on topics in primary care in which common diagnostic or therapeutic problems encountered in primary care practice are presented. Physicians interested in contributing to the series are encouraged to contact the series' editors. STEPHEN M. McPHEE, MD TERRIE MENDELSON, MD Assistant Editors

Cancer screening in older adults.

Adults aged 65 and older represent an increasingly important segment of the US population. Cancer is an important cause of death in this group. Screen...
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