Elderly patients with stage 2 to 3 CRC demonstrated significant gains in influenza vaccination after cancer diagnosis, with even more notable gains in mammography. These unexpected findings refuted our hypothesis that cancer’s intensive treatment would supplant this care. Instead, it may be that patients with stage 2 to 3 CRC, who are some of the least likely to use these services before diagnosis, are now receiving regular care from cancer care physicians who provide and/or advise use of these preventive services and are complying with these recommendations. Alternately, or in addition, these patients’ noncancer care physicians may more actively promote these services after cancer diagnosis. More frequent physician visits only partially explained the gains in influenza vaccination and mammography, however, suggesting that physician encouragement combined with patient attention to preventive care contributed to this change. These findings match those of research examining preventive testing among breast cancer survivors and controls,20
though this study is the first to follow preventive service use from before diagnosis through 7 years of survival.
Later-stage CRC patients did not demonstrate the same pattern in diabetes care. Despite frequent physician visits, patients with stage 2 to 3 CRC had less consistent increases and sometimes decreased diabetes testing compared with controls after initial treatment. Chronic disease care is more complex, and cancer care physicians may feel less comfortable both advising about and providing these services. Whether this lesser focus on diabetes care (and potentially other chronic conditions) has a deleterious effect is unknown, but studies demonstrating higher mortality among patients with co-morbid conditions in the first years after diagnosis suggest the importance of optimal management of comorbid conditions.8,10
What strategies might improve care quality for cancer patients’ chronic conditions like diabetes? Although cancer diagnosis and treatment may divert attention from other medical conditions, cancer patients are well connected with the medical care system. Early on, cancer patients receive care from cancer care physicians as well as primary care physicians and noncancer care specialists, who may have conducted screening or initial symptom evaluation; further out from diagnosis, cancer survivors primarily receive care from primary care physicians and noncancer care specialists.21
Building on these physician resources to improve the quality of cancer patients’ care is key. One important strategy is the development of strong partnerships between patients; their primary care physicians, who are specialists in chronic disease management; and their cancer care physicians. With strong partnerships in place, cancer care physicians could promote the importance of continuing primary care visits, and primary care physicians could ensure that oncologists receive historic clinical and psychosocial information that facilitates optimal patient care. Studies examining these partnerships emphasize communication from oncologists to primary care physicians to improve cancer-related care but do not highlight the importance of a bidirectional relationship or of cancer patients’ other health concerns.22–24
The Institute of Medicine endorses a coordinated primary and specialty care approach to addressing cancer patients’ needs, and suggests development of a survivorship care plan to facilitate optimal care.14
Future research systematically examining the effectiveness of strategies that enhance communication between primary and cancer care providers about cancer-related and chronic condition care is needed.
Neither controls nor cases uniformly received guideline-recommended preventive or diabetes care. This finding illustrates that neither frequent patient visits nor strong physician partnerships alone will ensure optimal preventive or chronic disease care. Continued implementation, evaluation, and development of care improvement strategies, such as chronic disease management models, to care for individuals with competing medical priorities such as a cancer diagnosis is important.25
Notably, patients with stage 0 to 1 CRC used medical care differently than both patients with stage 2 to 3 and controls, even before diagnosis. These early-stage CRC patients had the highest comorbidity rates and the highest hospitalization and outpatient visit rates before diagnosis. Their high annual preventive service use rates before diagnosis could be related to greater contact with health professionals or greater health-seeking behavior, which could in turn help explain their early-stage cancer diagnosis.
The many cancer cases in the longitudinal SEER-Medicare database made this study possible, yet these data are limited. They cannot document true preventive service rates. Influenza vaccination is available in many settings, including pharmacies, where patients may pay cash rather than submit a Medicare claim, and during hospitalization, where vaccination is bundled with other charges. In addition, this study’s annual mammography rates, which measure the combination of annual screening or diagnostic mammography, do not represent every two year screening mammography as was covered by the Medicare program during the study period. Despite these deviations from true population-based preventive service rates, comparing these services over time or between study groups is valid.
An additional limitation is that few evidence-based chronic disease care measures are available in Medicare claims. We chose diabetes care markers recommended by the American Diabetes Association that were likely to be captured reliably by claims. HgbA1c, which monitors blood glucose control, is widely used to assess quality of care but has not been associated with improvement in outcomes such as diabetes-related mortality.26
Claims data are also susceptible to secular coding changes. This is most obvious in the comorbidity index, which increased over time (eg, mean comorbidity index for 70 year olds in 1993 was 0.120 and in 1999 was 0.140). Also notable is that SEER data do not record cancer recurrence, although we censored an individual’s observation years starting with the first year in which there was evidence of treatment for recurrence (ie, chemotherapy and radiation administration). Because of attrition from death, the populations in each phase differed. To explore the influence of these population differences, we repeated analyses including only patients with at least one observation year in the survival phase and found similar point estimates but widened confidence intervals. Lastly, the study data are limited by their ages. Behavioral Risk Factor Surveillance System data demonstrate increases in flu vaccination, mammography, and cholesterol testing among the general population between the mid-1990s and late 2000s.27
However, given that there have been no major changes in the organization of oncology or primary care services during this time period, it is likely that the relationships between cancer diagnosis and receipt of preventive and diabetes services found in this study persist.