Disparities in surgical treatment of breast cancer: The influence of socio-demographic and tumor characteristics

Introduction: Breast cancer can be surgically treated using mastectomy or breast conserving surgery. Clinical trials have shown that mastectomy has no added survival benefit over breast conserving surgery. Recurrence of breast cancer has also been shown to be less than 5% at ten years following breast conserving surgery. Although some patients may still require a mastectomy based on certain tumor characteristics or personal preference, studies suggest that underserved populations are more likely to receive mastectomy.

Purpose: we sought to identify the association between surgical treatment modality, and individual level, county level and tumor characteristics, for patients diagnosed with breast cancer between years 2000 and 2011.

Methods: Using the Surveillance, Ends Result and Epidemiology (SEER) data, a retrospective study was conducted. Descriptive statistics were conducted using chi-square tests for categorical variables and student’s t-test for continuous variables. A two-level multilevel logistic regression was also conducted; individuals (level 1) were nested within counties (level 2). Dependent variable was type of surgical treatment (0=breast conserving; 1=mastectomy). We controlled for individual level, county level and tumor characteristics.

Results:  Bivariate descriptive statistics showed that rural residents were more likely to receive mastectomy compared to urban residents (46.67% vs. 36.56%; p-value=<0.0001). Residents of areas with lower poverty levels were less likely to receive mastectomy compared to residents of high poverty areas (34.44% vs. 46.92%; P-value=<0.0001). Compared to the baseline year, there was significantly decreased, but fluctuating likelihood of use of mastectomy across all years. On multivariate analyses rural residents were more likely to receive mastectomy compared to urban residents (OR=1.44; 95%=1.34-1.55). Compared to whites, blacks were less likely to receive mastectomy (OR=.91; 95% CI=0.89-0.93) while Asians/Pacific Islanders were more likely to receive mastectomy (OR=1.54; 95% CI=1.50-1.57). Hispanics were also more likely to receive mastectomy compared to non-Hispanics (OR=1.16; 95% CI=1.13-1.18). Compared to residents of low poverty areas, residents of high poverty areas were more likely to receive mastectomy (OR=1.52; 95% CI=1.48-1.58). Those who had high grade tumors were more likely to receive mastectomy compared to those who had low grade tumors (OR=1.32; 95% CI= 1.28-1.32).

Conclusion: Underserved populations could be at an increased risk for receipt of mastectomy following breast cancer diagnosis, compared to their counterparts. It is important to ensure that utilization of mastectomy for breast cancer treatment is evidence based. This can be achieved through continued education of physicians and patients.