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Originally published as JCO Early Release 10.1200/JCO.2007.11.9560 on June 4 2007 © 2007 American Society of Clinical Oncology.
To Screen or Not to Screen Older Women for Breast Cancer: A New Twist on an Old Question or Will We Ever Invest in Getting the Answers?
Lombardi Comprehensive Cancer Center, Cancer Control Program, Georgetown University Medical Center, Washington, DC Women 65 or older (hereinafter referred to as older women) constitute one half of new breast cancer patients each year. With the graying of America, the absolute number of patients in this age group will double by the year 2030. The efficacy of screening mammography for improving survival of this growing older population has never been demonstrated in a randomized trial, leading most groups to qualify their screening recommendations for older women, especially women older than age 74 or 79.1-3 However, annual mammography is recommended for breast cancer screening surveillance for all women after treatment for breast cancer, despite the absence of clinical trial evidence for effectiveness in older women (or any other age group).4-5 Filling this evidence gap was the goal of the study in this issue of the Journal of Clinical Oncology by Lash and colleagues.6 Lash et al used data from a large cohort of older breast cancer survivors with stage I and II disease receiving care in managed care settings to examine the protective effect of mammography on breast cancer and all cause mortality. They found that there was a striking 31% (95% CI, 18% to 48%) reduction in the odds of death for each additional surveillance mammogram, after considering tumor characteristics, comorbidity, surgery, and other covariates. Unfortunately, even with guaranteed access in the managed care environment, use of mammography among survivors fell well below the recommended annual recommendation, with 40% of decedents having no mammograms, 32% having only one, and only 41% of survivors having four or more mammograms in the 5-year follow-up period. Given these rates of surveillance and an estimated prevalence of older breast cancer survivors of 2.3 million, the results of Lash and colleagues suggest that as many as 500,000 older women will die of their breast cancers due to suboptimal mammography surveillance. One assumes that the survival advantage afforded to older breast cancer survivors by surveillance mammography is a result of the detection of curable new primaries in the contralateral breast. There is also growing evidence that survival is improved when surveillance detects early locoregional recurrences of the primary breast cancer.7 The fact that overall nonbreast cancer–specific survival was greater among women who underwent surveillance mammography in the Lash et al study also suggests that part of the benefit observed may have been due to observational bias (eg, unobservable or unmeasured selection of healthier women to mammography). However, the authors did conduct statistical analyses to try to correct for any such bias (propensity scoring), and the results of a strong survival benefit were robust. Randomized trials can avoid potential observational biases, but we are left with the persistent dilemma that older women have not been included in trials in sufficient numbers to provide the necessary evidence base. Moreover, as new technology evolves, this situation is being perpetuated. For example, a recent high-profile article from the American College of Radiology Imaging Network (ACRIN) trial demonstrated that magnetic resonance imaging (MRI) can detect new breast cancers in survivors that were not seen on clinical examination or mammography.8 The average age in the MRI study was 53.3 ± 11.4 years; therefore, there were no women 65 or older included, leaving us to wonder if MRI should be applied in older patients. With continued gains in life expectancy, improvements in survival from breast cancer (and other major cancer sites), and increases in incidence with age, clinicians will be caring for an ever-increasing number of older breast cancer patients and survivors. Without a major shift in emphasis in clinical trials and new investments in understanding the impact of therapy and technology on older populations, we will continue to practice with limited trial evidence. In this situation, as demonstrated by the study by Lash et al, well-designed observational studies can provide a reasonable level of evidence. This high-quality observational research was facilitated by the development of the Cancer Research Network, a National Cancer Institute (NCI) –funded collaboration between 12 large, mature, managed care systems, including Group Health Cooperative, the Harvard Pilgrim Health Plan, Henry Ford Health Systems, Fallon Community Health Plan, and Kaiser Permanente in six regions.9 Managed care research networks have several potential advantages for studying questions about cancer care in older women. First, access is removed from the equation in survival outcomes. Second, they include large proportions of the population from almost all regions of the United States, providing an alternative universe for population-based studies. Third, the availability of computerized administrative databases linked to laboratory and pathology data and often electronic medical records allows careful delineation of disease and interventions and comprehensive, cost-efficient long-term follow-up. Thus, this network provides high-quality data for observational research and can fill critical gaps in our knowledge, especially in situations where large-scale clinical trials are not likely to be mounted. This research is also an excellent example of how, in the absence of clinical trials, NCI's investment in an infrastructure for well-designed health services research can provide data critical to clinical care and policy. Unfortunately, only 2.73% of NCI's current $4.7 billion budget is invested in health services research, down from 3.5% in 2001.10 Also, considering that more than one half of all cancer cases occur in older populations, less than 10% of their health services research portfolio specifically targets older groups.11 Even the National Institute on Aging, the agency charged with research in older populations, only devotes 8.23% of its budget to health services research.10 The Agency for HealthCare Research and Quality has historically funded cancer health services research. Unfortunately, that agency's budget has suffered dramatic cuts and only funds a very small number of investigator-initiated research grants. Perhaps it is time to consider inclusion of older populations as a criterion, like consideration of women, minorities, and children, for accountability as human subjects in all new National Institutes of Health research proposals and to make health services research a spending priority. Overall, high-quality health services research like that conducted by Dr Lash and his colleagues fills gaps left by clinical trials and can guide clinical care and policy for the growing older population of cancer survivors. Greater federal investment in health services research for an aging population will be critical to meeting the goal of reducing the burden of cancer in older Americans, the group that already carries the bulk of the overall US cancer burden. Until then, all clinicians should be vigilant in insuring that their older breast cancer patients understand the value of mammography. In addition, given the level of evidence provided by Lash and colleagues, physicians should feel confident in recommending this modality to all their patients. Physician recommendation of proven effective interventions remains one of our strongest tools in the war against cancer. Health services research is another important part of the strategy in this battle: let us arm the cancer control community with the funding necessary to fight and win this war. AUTHOR'S DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The author(s) indicated no potential conflicts of interest. NOTES published online ahead of print at www.jco.org on June 4, 2007 REFERENCES
1. Smith RA, Saslow D, Sawyer KA, et al: American Cancer Society Guidelines for Breast Cancer Screening: Update 2003. CA Cancer J Clin 53:141-169, 2003 2. Kerlikowske K, Salzmann P, Phillips KA, et al: Continuing screening mammography in women aged 70 to 79 years: Impact on life expectancy and cost-effectiveness. JAMA 282:2156-2163, 1999 3. United States Department of Health and Human Services: United States Preventive Services Task Force. http://www.ahcpr.gov/clinic/uspstfix.htm 4. Rosselli Del Turco M, Palli D, Cariddi A, et al: Intensive diagnostic follow-up after treatment of primary breast cancer: A randomized trial–National Research Council Project on Breast Cancer follow-up. JAMA 271:1593-1597, 1994 5. Khatcheressian JL, Wolff AC, Smith TJ, et al: American Society of Clinical Oncology 2006 Update of the Breast Cancer Follow-up and Management Guideline in the Adjuvant Setting. J Clin Oncol 24:5091-5097, 2006 6. Lash T, Fox MP, Buist DSM, et al: Mammography surveillance and mortality in older breast cancer survivors. J Clin Oncol 25:3001-3006, 2007 7. Wapnir IL, Anderson SJ, Mamounas EP, et al: Prognosis after ipsilateral breast tumor recurrence and loco regional recurrences in five National Surgical Adjuvant Breast and Bowel Project node-positive adjuvant breast cancer trials. J Clin Oncol 24:2028-2037, 2006 8. Lehamn CD, Gatsonis C, Kuhl CK, et al: MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer. N Engl J Med 356:1295-1303, 2007 9. Wagner EH, Greene SM, Hart G, et al: Building a research consortium of large health systems: The Cancer Res Network. J Natl Cancer Inst Monogr 35:3-11, 2005 10. Coalition for Health Services Research: Federal Spending for Health Services Research. http://www.chsr.org/AHfundingreport1206.pdf 11. National Institutes of Health, National Cancer Institute: Cancer Control and Population Sciences. http://dccps.nci.nih.gov/
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Copyright © 2007 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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