This study among older women diagnosed and treated for a first primary breast cancer in integrated healthcare systems found a decline in the use of mammography over time after completion of initial therapy. We found that women at higher risk of recurrence because of being diagnosed at later stage or not receiving radiation therapy after breast-conserving therapy were less likely to receive mammograms. Women with visits to oncology or breast cancer surgery specialists during a year were much more likely to receive a mammogram during that year than those without such visits.
Several previous studies have examined use of surveillance mammograms among breast cancer survivors using a variety of data sources. Studies using the combined Surveillance Epidemiology and End Results/Medicare data have relied on Medicare claims and found rates among women age 65 and older ranging from 62%7
over 2 years of follow-up to 78% during the initial period postdiagnosis.10
In a previous study among health systems participating in the Cancer Research Network that included women age 55 and older diagnosed in 1996 and 1997, we found slightly lower rates.11
That study and those using Medicare data did not have access to medical records and were missing information on the reason for mammography orders or the type of ordering physician. A number of studies have found nonreceipt of radiation therapy after breast-conserving surgery associated with lower rates of follow-up mammography.8,9,10
Older age has also been consistently associated with lower rates.
Strengths of this study include the existence of a carefully defined sample, access to complete medical records, and a high level of follow-up. Our loss to follow-up because of disenrollment during the 4 years was 3%. There are several limitations. We ascertained receipt of surveillance mammography through medical record review. Although the women included in the study were enrollees of health plans that are responsible for their ambulatory and in-patient medical care and the medical records are thorough, we may not have captured some mammograms that did not produce negative findings if they were not documented. This would lead to an underestimate of the rate of mammography. The rates of mammography found in this study may not be generalizable to older women who receive medical care in the fee-for-service system, where rates may be lower.
Guidelines for the follow-up of women with a history of breast cancer recommend annual surveillance mammography.6
The impact of annual mammography on survival has not been evaluated in randomized trials; trials of intensive surveillance have used annual mammography as the comparison standard of care with the assumption that surveillance mammography is necessary to diagnose recurrences and new primary breast cancers at an early stage when they have the best prognosis.14,15
Population-based screening for cancers of the breast has been shown to reduce the risk of death from breast cancer,16
and routine mammograms after breast cancer diagnosis have been found to detect subsequent contralateral disease at an earlier stage than the initial breast cancer.17
Several studies have suggested better outcomes among women whose local recurrences were detected through surveillance mammography18
, and recent studies of surveillance mammography in older women with breast cancer have found an association with both improved survival and reduction in cancer-related worries.19
The potential importance of surveillance mammography is highlighted by the results of 2 studies based on the experiences of the women followed in the BOW project. More than 5% developed a local or regional breast cancer recurrence during the 10 years of follow-up.20
These recurrences occurred as long as 8 years after initial diagnosis, and 43% were identified before they were symptomatic. Three percent were diagnosed with a new primary breast cancer in the contralateral breast as long as 9 years after the first diagnosis, and 62% were identified when presymptomatic. Assessment of the impact of surveillance mammography in this group found that each additional surveillance mammogram was associated with a 0.69-fold decrease in the odds of breast cancer mortality (95% CI 0.52, 0.92).21
Receipt of surveillance mammography by breast cancer survivors is a product of several factors, including physician recommendations, access to oncology specialists, the existence of clinical reminder systems, and, most importantly, the decisions of the women themselves to participate in this aspect of their medical care. Our finding of a strong association between visits to oncologists and breast cancer surgeons and receipt of surveillance mammography suggests that older breast cancer survivors who do not visit these specialists may not be aware of the role of surveillance mammography within their survivorship care. The question of when to stop surveillance mammography is not addressed in this study, although the benefits of surveillance mammography clearly extend to at least 5 years after initial diagnosis. The study also does not identify when surveillance mammography is futile because of comorbid conditions and short life expectancy. However, the low rate of surveillance mammograms in women who died within 12 months suggests that the clinicians caring for these women did not continue surveillance mammography inappropriately. Our concern remains that women who could potentially benefit from surveillance mammograms and their physicians are more likely to underappreciate when these studies still offer benefit than when they are futile.
Whether care is provided by primary care physicians alone or in collaboration with cancer specialists, older breast cancer survivors need to be aware of their increased risk of recurrences and second primaries and the potential for surveillance mammography to detect these new occurrences asymptomatically. Decisions by physicians and patients to discontinue surveillance mammography should be informed by the risks and benefits while taking into account the patient’s future life expectancy, values, and preferences.
As highlighted in the recent Institute of Medicine Report, From Cancer Patient to Cancer Survivor: Lost in Transition,22
there is a dearth of evidence about cancer survivors’ expectations and experiences with follow-up care. In the general population of women, physician recommendations are strongly associated with receipt of screening mammography.23
The health systems included in this study all track mammography utilization among their enrollees following the Health Plan Employer Data and Information Set guidelines. These guidelines do not call for breast cancer screening for women more than the age of 69 with no specific mention of breast cancer survivors.
In this study, women without a visit to an oncologist or breast cancer surgeon during a year had low rates of mammography during that year. Moreover, the rates of such visits steadily declined during the 4 years of follow-up. Relying on specialist care for on-going surveillance may undermine continuity of care, leaving survivors poorly prepared for long periods of potentially increased risk. In contrast to this finding, several randomized trials have demonstrated that primary care physicians can provide ongoing surveillance care to breast cancer survivors with comparable outcomes,24
similar health-related quality of life and costs, and greater satisfaction. Within 1 of the healthcare delivery systems participating in this study, implementation of an organized breast cancer screening program for its general enrolled population of women age 40 and older substantially increased the rate of mammography screening and lowered the rate of late stage diagnosis.25
Similar strategies that target healthcare systems, clinicians, patients, and public policy need to be developed for surveillance among breast cancer survivors.