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© 2003 American Society for Clinical Oncology Quality of NonBreast Cancer Health Maintenance Among Elderly Breast Cancer Survivors
From the Division of Population Sciences, Center for Outcomes and Policy Research, Breast Oncology Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA. Address reprint requests to Craig C. Earle, MD, Center for Outcomes and Policy Research, Dana-Farber Cancer Center, 44 Binney St., Boston, MA, 02115; email: craig_earle{at}dfci.harvard.edu.
Purpose: To assess the quality of preventive health care, the role of health care participation, and the patient and provider characteristics associated with high-quality care for breast cancer survivors. Methods: We analyzed the 1997 to 1998 Medicare data of elderly women who were diagnosed with nonmetastatic breast cancer in 1991 or 1992 while living in a Survival, Epidemiology, and End Results (SEER) tumor registry area and who survived to the end of 1998 without evidence of cancer recurrence. Controls were matched for age, race, and geographic location. Results: The 5,965 breast cancer survivors received more preventive services (influenza vaccination, lipid testing, cervical and colon screening, and bone densitometry) than matched controls. Among both groups, those who were younger, nonAfrican-American, of higher socioeconomic status, living in urban areas, and receiving care in a teaching center were most likely to receive high-quality health maintenance. Those survivors who continued to see oncology specialists were more likely to receive appropriate follow-up mammography for their cancer, but those who were monitored by primary care physicians were more likely to receive all other noncancer-related preventive services. Those who saw both types of practitioners received more of both types of services. When the control group was restricted only to women actively undergoing mammographic screening before the study period, receipt of preventive services was similar. Conclusion: Breast cancer survivors receive high-quality preventive services, but disparities on the basis of nonmedical factors still exist. Cancer follow-up may provide regular contact with the health system, maximizing the likelihood of receiving appropriate general medical care.
BREAST CANCER is the most common cancer in women. With advances in both screening and treatment, the 5-year survival rate is now 85%,1 and 61% of these women are still alive at 15 years.2 As a result, there are an estimated 2 million women in the United States who are breast cancer survivors,3,4 a number that is expected to continue to grow as the incidence of breast cancer increases, breast cancer mortality declines, and our population ages. Previous studies have indicated that there are important competing risks for women with breast cancer.5,6 In one study of breast cancer survivors identified through the Connecticut tumor registry, heart disease and gynecological cancers were identified as significant contributors to mortality.7 Analysis of public release data from the National Cancer Institute (NCI) Survival, Epidemiology, and End Results (SEER) program indicates that the major causes of nonbreast cancer mortality among women with a history of breast cancer are heart disease and stroke; colorectal, lung, and gynecologic cancers; chronic lung disease; and complications of diabetes. These do not differ from the causes of death seen in matched controls drawn from the National Center for Vital Statistics. The risk of several of these illnesses can potentially be lowered by appropriate preventive services such as screening for colon cancer or cardiovascular disease, immunization to prevent influenza, and recommendations for lifestyle interventions such as diet and smoking cessation. This observation led us to question whether there were differences in the nonbreast cancer medical care breast cancer survivors receive compared with the general population and how sociodemographically vulnerable subgroups of survivors fare compared with others. One could hypothesize that survivors may receive less care because of an underlying sense that their cancer is their greatest threat to life or because cancer patients may rely on specialists for their primary care. Conversely, they may receive higher-quality care because they have already been engaged in the medical system or because their physicians may be more vigilant, having already identified a serious illness. If the latter were true, a prior diagnosis of breast cancer might mitigate the usually observed poorer quality of care received by certain subgroups of patients. To address these issues, we used population-based administrative data to assess and compare the use of standard preventive services among breast cancer survivors and matched controls.
Data Sources We primarily used two data sources: the NCI SEER and the Health Care Financing Administration (HCFA) Medicare database. The 11 tumor registries participating in the SEER program capture about 97% of their incident cases,8 covering a representative sample9 of approximately 14% of the United States population.10 Registries collect data on each patients age, sex, race and ethnicity, cancer site, stage, histology, date of diagnosis, and date and cause of death. They also record initial treatment data on surgery and radiation received in the first 4 months after diagnosis. However, SEER does not provide information on later treatments. To monitor these patients longitudinally, Medicare claims for patients older than age 65 years have been linked to the SEER registry data. The Medicare data set includes files through 1998 for inpatient and outpatient care, physician and laboratory billings, and bills for home health and hospice care. For patients age 65 years and older captured by the SEER registries, 94% have been linked to Medicare.11 Census-level sociodemographic data have also been linked to these patient cases, allowing us to create socioeconomic quintiles on the basis of the race and age-adjusted income, wealth, and education in each patients census tract in the 1990 census. Combining SEER data with Medicare data provided us with information on initial diagnosis and later cancer treatment, as well as the downstream medical care for cancer survivors.
Cohort Selection Controls were obtained from a 5% random sample of Medicare patients with no history of cancer, as determined by having never appeared in a SEER tumor registry for any reason and having no claims for a cancer diagnosis, matched to each case on the basis of age, sex, race, and geographic location (living in the same SEER registry area). Patients were excluded if they were enrolled in a Health Maintenance Organization (HMO) at any time during the study period or if they were not eligible for both parts of Medicare, as they would not have complete treatment information. We then compared the noncancer-related preventive services received by survivors with those received by controls in the 2 years of 1997 and 1998. Analysis was restricted to these latter years to avoid assessing patients who may not have been considered survivors by all of their caregivers, which could potentially have biased comparisons of preventive health resource use.
Definitions of Preventive Services
Definitions of Explanatory Variables To investigate the effect of access and participation in the health care system on receipt of services, as opposed to differential treatment of cancer survivors by doctors, we repeated the analyses restricting the control group to those women who had had a mammogram in 1991 and 1992, the same 2-year period when the survivors were diagnosed with their breast cancer. In this way, both groups consisted only of patients who were actively participating in the health care system 5 years previously. To assess the type of physicians patients were seeing, we categorized physicians on the basis of their specialty identification in Medicare. Oncology specialists were defined as subspecialists in medical oncology or hematology-oncology (HCFA specialty codes 83 or 90, respectively), radiation oncologists (code 92), or surgeons (code 02, general surgery; code 91, surgical oncology). The analyses were also carried out with surgeons not classified as oncologists; these results were similar and are not reported. Primary care physicians were identified with the following provider codes: 01, general practice; 11, internal medicine; 08, family practice; 16, obstetrics/gynecology; 38, geriatric medicine; and 70, multispecialty group practices.
Analytic Considerations
A total of 6,365 nonmetastatic breast cancer patients met the eligibility criteria of surviving and continuously participating in both parts of Medicare through to the end of 1998 and were matched with controls. After we excluded those in each group with evidence of chemotherapy or radiation use, receiving hospice services, or with cancer diagnoses in their bills during the study period, there were 5,965 survivors and 6,062 controls. When this small excess of controls was eliminated, results for all analyses were similar and are not reported.
Patient Characteristics
Use of Preventive Services Table 2
Relationship Between Previous Health Care Participation and Utilization of Preventive Services To explore the effect of access and participation in the health care system on receipt of services, we repeated the analyses restricting the control group to those women who had had a mammogram in the same 2-year period when the patients were diagnosed with breast cancer. As the last column of Table 2
Relationship Between Patient Characteristics and Use of Preventive Services
Relationship Between Provider Characteristics and Use of Preventive Services In addition to receiving care in a teaching hospital, the type of provider accessed strongly predicted the receipt of preventive services. Among breast cancer survivors, 2,466 (41%) followed-up only with primary care or other physicians and were not seen by an HCFA-identified oncology specialist. Two hundred and three patients (4%) were seen only by an oncologist, and 3,075 (52%) were seen by both types of physicians. As Table 4
We found that breast cancer survivors, as a group, appear to have received high-quality health maintenance when compared with matched controls. We observed that restriction of the control group to those engaged in active breast screening erased the differences, and that patients seeing both primary care and specialist physicians received the highest-quality care. Consequently, it appears that breast cancer patients enhanced participation in the health care system may explain their better quality of care. Even within this engaged group of patients, however, inequities still exist on the basis of nonmedical factors such as race and wealth. The baseline characteristics of the survivor and control groups in this study were well matched. The population was quite elderly, largely because of the 5-year survival requirement, but restriction to a younger cohort did not change the results. Rates of care in teaching institutions were likely underestimated because this could only be established for patients admitted to the hospital. Interestingly, congestive heart failure was more common among survivors, possibly related to prior receipt of anthracyclines or chest irradiation. Myocardial infarction, a severe, acute event likely to be less affected by patterns of health care seeking, was actually more common among controls. This suggests that comorbidities were being captured well in both groups, not simply that survivors had more comorbid conditions documented by virtue of having more medical contacts (detection bias). The higher rate of diabetes observed in the survivor population might be explained because obesity in postmenopausal women is a risk factor for both breast cancer and diabetes. In absolute terms, the rates of use of preventive services presented in this article likely represent conservative estimates of the true rates in both groups. It is possible, for example, that some women received influenza vaccination or mammography through free programs not captured by Medicare. It is not expected that this would occur differentially between the two groups, however, making comparison of rates internally valid. The finding of mammography in 85% of breast cancer survivors younger than age 75 years 5 years after their cancer diagnosis appears consistent with expectations. The rates could also be low because of lack of consensus about the use of several of these preventive health measures in older patients. However, the results of our analyses were similar when patients were restricted to those younger than age 75 years. Having established that rates of preventive service use were different, we next attempted to determine whether this was because women diagnosed with breast cancer were regular participants in the health care system or because they were being treated differently by physicians. When we controlled for health care participation by limiting the control group to only those women who had previously undergone mammographic screening, all differences between the groups were removed. This finding reinforces existing evidence that health care participation is likely an important determinant of the quality of care patients receive.17 It is impossible to know whether it was the patients who were proactive in seeking preventive health behaviors or whether they had physicians who were attuned to providing preventive care. Although Grunfeld et al18,19 were unable to show that specialist follow-up in the United Kingdom improves outcomes such as survival or quality of life, here we present data indicating that it may improve some processes of cancer carein this case, surveillance mammography. These seemingly conflicting results may be related to the different roles of the consulting specialist in the health care systems of the United States and United Kingdom. Although it is unknown whether the observed patterns of care are mostly driven by patient health-seeking behaviors or physician diligence, those survivors that continued to see oncology specialists were more likely to receive appropriate follow-up care for their cancer, whereas those that were observed by primary care physicians were more likely to receive standard nonbreast cancer-related preventive services. Patients that continued to see both types of physicians received the best preventive care overall. Interestingly, those followed only by oncologists were less likely to receive cervical or colon cancer screening, indicating that the oncologists may be too focused on the follow-up of the previously diagnosed cancer to pay attention to other cancer-related issues. There are a number of limitations to our analysis. It is unknown whether the relationships we observed determine the likelihood of receiving preventive services or whether patients with these characteristics are more likely to seek preventive services. Because we examined processes of care in patients who had to be alive to be eligible, by design our study could not assess the outcomes of such care. We can only apply these results to elderly women in a fee-for-service environment. The analysis relies on the accuracy of billing data. It is impossible to know whether all of the survivors were truly free of disease, and some procedures may have been carried out for diagnostic reasons, not as part of routine care (eg, screening colonoscopy only became covered by Medicare in the last year of the study; however, a systematic difference between the two groups would not be expected). Last, defining oncologists on the basis of their designation in Medicare may overlook physicians who are not board-certified, but who nonetheless specialize in cancer care.20 The strengths of this study are that these are national-level population-based data, with a large sample size, consisting of patients with uniform insurance so financial incentives should not affect practice. Improvements in screening and treatment for breast cancer have decreased the 5-year mortality rate for this disease and increased the number of breast cancer survivors. These women are at risk from other, nonbreast cancer-related illness, however. Because many breast cancer survivors are regular participants in the health care system, physicians caring for them have a ready opportunity not only to diagnose and manage disorders unrelated to breast cancer but to prevent many of them. The implications of this study are that being engaged in medical care for one reason may have beneficial effects in other areas. Health care participation is obviously not the whole story, however. Even for patients actively engaged in specialty health care, nonmedical factors such as race, socioeconomic status, geography, and teaching status of hospitals were associated with disparities in preventive medicine. Still, although follow-up after definitive cancer treatment has not been shown to improve cancer-specific survival19,21 it may serve the purpose of keeping patients in regular contact with a variety of health care providers. Whether these procedures translate into better health outcomes requires further study but could suggest a role for observation of these patients by both specialist and generalist.22
Supported by grants from the Massachusetts Department of Public Health (MDPH 34080066068) and the Friends of the Dana-Farber Cancer Institute. Presented at the thirty-seventh annual meeting of the American Society of Clinical Oncology, May 1215, 2001, San Francisco, CA.
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19. Grunfeld E, Mant D, Yudkin P, et al: Routine follow-up of breast cancer in primary care: Randomised trial. Br Med J 313:665669, 1996
20. Earle CC, Neumann PJ, Gelber RD, et al: Impact of referral patterns on the use of chemotherapy for lung cancer. J Clin Oncol 20:178692, 2002
21. Tomiak E, Piccart M: Routine follow-up of patients after primary therapy for early breast cancer: Changing concepts and challenges for the future. Ann Oncol 4:199204, 1993
22. Burstein HJ, Winer EP: Primary care for survivors of breast cancer. N Engl J Med 343:10861094, 2000 Submitted March 12, 2002; accepted January 13, 2003.
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Copyright © 2003 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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