Rates of Reexcision after Breast Cancer Surgery

Efforts at healthcare reform have included a focus on increased physician and hospital accountability and transparency of outcomes. Mortality is a common measurement tool used to assess surgical outcomes, but for procedures associated with low mortality, assessing outcomes as a measure of quality of care has been challenging.

Partial mastectomy as initial treatment for breast cancer is a common cancer surgery, with 60% to 75% of patients with breast cancer undergoing partial mastectomy as first-line treatment. Mortality estimates for partial mastectomy are <1%; researchers caution, however, that low mortality does not translate directly to high quality of care.

Noting that there are no easily identifiable quality measures allowing for comparisons of outcomes for partial mastectomy among surgeons and hospitals, the researchers recently conducted a study expanding an earlier analysis on reexcision rates following initial partial mastectomy at a high-volume university-based breast center to include 3 geographically diverse health systems and their surgeons. They reported results of the expanded analysis in the Journal of the American Medical Association [2012;307(5):467-475].

The researchers hypothesized that defining predictors of reexcision and the extent of variability would allow for complete evaluation of the utility of reexcision as a meaningful measure of quality of breast cancer surgery. The new analysis was designed to assess variations among physicians and hospitals in reexcision rates following partial mastectomy, as well as whether patient demographic, clinical, and pathologic criteria were associated with an increased likelihood of reexcision following initial breast-conserving surgery for invasive breast cancer.

The analysis included data from women with invasive breast cancer who underwent partial mastectomy at 4 institutions (1 university hospital [University of Vermont] and 3 large health plans [Kaiser Permanente Colorado, Group Health, and Marshfield Clinic]). Predictors of reexcision were identified using logistic regression including surgeon-level random effects. The primary outcome measure was incidence of reexcision.

After applying exclusion criteria, the researchers included 2206 women with 2220 newly identified invasive breast cancer undergoing a breast-conserving first surgical procedure in the analysis. Of those, 22.9% (n=509) underwent additional surgery on the affected breast; among those patients, 89.2% (n=454) underwent a single reexcision, 9.4% (n=48) underwent 2 reexcisions, and 1.4% (n=7) underwent 3 reexcisions. Among all patients undergoing initial breast conservation, a total mastectomy was subsequently performed in 8.5% (n=190).

Mean age of patients in the study was 62.16 years (range, 30-98 years), and 92.8% of those with reported race/ethnicity were non-Hispanic white. Mean invasive tumor size was 14.7 mm, and 22.0% of patients were node positive.

Factors associated with increases in reexcision included the initial procedure being an open surgical breast biopsy (45.0%; 95% confidence interval [CI], 35.6%-53.4% vs 10.7%; 95% CI, 9.3%-12.2%; P<.01). Based on univariate analysis, women <35 years of age (reexcision rate, 37.5%; 95% CI, 4.0%-71.0%), with <18.5 body mass index (reexcision rate, 40.0%; 95% CI, 15.2%-64.8%), and initial margins of <1 mm (reexcision rate, 47.9%; 95% CI, 42.0%-53.9%) were all more likely to have reexcision.

Rates of reexcision based on margin status following initial surgery were 85.9% (95% CI, 82.0%-89.8%) for initial positive margins, 47.9% (95% CI, 42.0%-53.9%) for <1.0-mm margins, 20.2% (95% CI, 15.3%-25.0%) for 1.0- to 1.9-mm margins, and 6.3% (95% CI, 3.2%-9.3%) for 2.0- to 2.9-mm margins.

There were significant variations in reexcision rates for patients with negative margins among surgeons (range, 0%-70%; P=.003) and among institutions (range, 1.7%-20.9%; P<.001). Following adjustments for case mix, the analysis did not reveal any association between reexcision rates and surgeon procedure volume (P=.92).

The researchers cited the lack of data regarding decision making as a major limitation to the study; they noted, however, that the study “is likely more generalizable to community-based breast cancer management in which reporting of breast pathology also has considerable variability.”

In summary, the researchers said that “substantial and institutional variation were observed in reexcision following partial mastectomy in women with invasive breast cancer.” They commented that “continued comparative effectiveness research of breast cancer surgery required further attention to better determine the association of initial surgical care with long-term patient outcomes.”