January 31, 2012
Rate of additional surgery varies after partial mastectomy
Group Health, Kaiser, Marshfield, and UVM results in JAMA
Seattle, WA—Nearly one in four women who undergo a partial mastectomy for treatment of breast cancer have another surgery to remove additional tissue (reexcision), and there is substantial surgeon and institutional variation in the rate of reexcisions that cannot be explained by patients’ clinical characteristics, according to a study in the February 1 Journal of the American Medical Association.
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The current environment of health care reform in the United States calls for increasing physician and hospital accountability and transparency of health care outcomes. “Breast-conserving therapy, or partial mastectomy, is one of the most commonly performed cancer operations in the United States,” according to background information in the article. “Currently, there are no readily identifiable quality measures that allow for meaningful comparisons of breast cancer surgical outcomes among treating surgeons and hospitals.”
Partial mastectomy is optimally performed by achieving adequate surgical margins (the rim of normal tissue around the breast cancer) during the initial surgical resection while maintaining maximum cosmetic appearance of the breast. Failure to achieve appropriate margins at the initial operation will require additional surgery. These additional operations can produce considerable psychological, physical, and economic stress for patients and delay use of recommended supplemental therapies. “Thus, the effect of reexcision on altering a patient's initial treatment of choice is significant,” the authors wrote.
participate in the HMO Cancer Research Network (Group Health, Kaiser Permanente Colorado, and Marshfield Clinic). Erin J. Aiello Bowles, MPH, a research associate at Group Health Research Institute, was a co-author. The data from the study sites were coded as A, B, C, and D. Data were obtained from electronic medical records and chart abstraction of surgical, pathology, radiology, and outpatient records. The study included 2,206 women with 2,220 newly identified invasive breast cancers who underwent a breast-conserving first surgical procedure. The average age for patients was 62 years, and 92.8 percent of patients with reported race/ethnicity were non-Hispanic white. Overall, 509 patients (22.9 percent) underwent additional surgery on the affected breast. Among these patients, 454 (89.2 percent) underwent a single reexcision, 48 (9.4 percent) underwent two reexcisions, and 7 (1.4 percent) underwent three reexcisions. Among all patients undergoing initial breast conservation, a total mastectomy was subsequently performed in 190 patients (8.5 percent).
“Reexcision rates for margin status following initial surgery were 85.9 percent for initial positive margins [cancer cells at the edge of the removed tissue], 47.9 percent for less than 1.0-mm margins, 20.2 percent for 1.0- to 1.9-mm margins, and 6.3 percent for 2.0- to 2.9-mm margins. For patients with negative margins [no cancer cells at the outer edge of the tissue that was removed], reexcision rates varied widely among surgeons (range, 0 percent to 70 percent) and institutions (range, 1.7 percent to 20.9 percent). Reexcision rates were not associated with surgeon procedure volume after adjusting for case mix,” the authors wrote.
The researchers also observed variation in the reexcision of positive margins among institutions, with rates ranging between 73.7 percent and 93.5 percent. This may reflect institutional variation in surgeons’ training, regional variation in interpretation of the required criteria for reexcision, or both, they wrote.
“Our study highlights the value of multicenter observational studies in demonstrating variability in health care across geographic regions and different health systems, with uniform data collection instruments. The long-term effect of this variability is beyond the scope of our study, but it is feasible that outcomes such as local recurrence and even overall survival could be affected by variability in initial surgical care. Even in the absence of effects on local control, the wide level of unexplained clinical variation itself represents a potential barrier to high-quality and cost-effective care of patients with breast cancer. Continued comparative effectiveness research of breast cancer surgery requires further attention to better determine the association of initial surgical care with long-term patient outcomes,” the authors concluded.
This work was funded by a grant from the American Recovery and Reinvestment Act of 2009 by the National Institutes of Health.
Cancer Research Network
The HMO Cancer Research Network (CRN) consists of the research programs, enrolled populations, and data systems of 14 health maintenance organizations nationwide.
The overall goal of the CRN, and the National Cancer Institute initiative under which it was funded, is to use this consortium of delivery systems to conduct research on cancer prevention, early detection, treatment, long-term care, surveillance, and cancer communication and dissemination and implementation research. A portfolio of research studies encompasses cancer control topics ranging from modification of behavioral risk factors such as smoking to cancer care at the end of life. Through this expansive program of research, the CRN seeks to improve the effectiveness of preventive, curative, and supportive interventions for both major cancers such as breast, colon and lung, and rare tumors. The CRN is also uniquely positioned to study the quality of cancer care in community-based settings. As a reflection of its commitment to improving quality of care, the Agency for Healthcare Research and Quality is cooperatively supporting the CRN with the NCI. The CRN research centers comprise scientists with expertise in epidemiology, health services, behavioral medicine, and biostatistics, as well as primary and specialty care clinicians. This environment facilitates a multidisciplinary approach to studying ways to improve cancer care. Group Health Cooperative is the lead site for the Cancer Research Network.
Group Health Research Institute
Group Health Research Institute is the research arm of Seattle-based Group Health Cooperative, a consumer-governed, nonprofit health care system. Founded in 1947, Group Health Cooperative coordinates health care and coverage. Group Health Research Institute changed its name from Group Health Center for Health Studies in 2009. Since 1983, the Institute has conducted nonproprietary public-interest research on preventing, diagnosing, and treating major health problems. Government and private research grants provide its main funding.