Impacts of neighborhood characteristics on treatment and outcomes in women with ductal carcinoma in situ of the breast

Background: This study examines associations of neighborhood characteristics with treatment and outcomes of ductal carcinoma in situ (DCIS) of the breast. Methods: From the Missouri Cancer Registry, we identified 9,195 women with DCIS diagnosed between 1996 and 2011. A composite index using U.S. Census data and American Community Survey data was developed to assess census tract-level socioeconomic deprivation, and rural-urban commuting area codes were used to define rural census tracts. ORs and 95% confidence intervals (CIs) of the treatment were estimated using logistic regression. Hazard ratios (HRs) of DCIS outcomes were estimated using Cox proportional hazards regression. Results: Women in the most socioeconomically deprived census tracts were more likely than those in the least deprived to have mastectomy (OR = 1.44; 95% CI, 1.25- 1.66; Ptrend < 0.0001), no surgery (OR = 1.54; 95% CI, 1.02- 2.30; Ptrend = 0.04), no radiotherapy post-breast conserving surgery (OR = 1.90; 95% CI, 1.56-2.31; Ptrend<0.0001), delayed radiotherapy (OR = 1.26; 95% CI, 1.01-1.57; Ptrend= 0.02), and ipsilateral breast tumors (HR = 1.59; 95% CI, 1.07-2.38; Ptrend = 0.03). There was no significant difference in risk of contralateral breast tumors. Compared with urban women, rural women had significantly higher odds of underutilization of radiotherapy (OR = 1.29; 95% CI, 1.08-1.53). Rural locations were not associated with risk of ipsilateral or contralateral breast tumors. Conclusions: Neighborhood socioeconomic deprivation was associated with higher risks of suboptimal treatment and ipsilateral breast tumors. While DCIS treatment significantly varied by rural/urban locations, we did not observe any statistically significant rural-urban differences in risks of second breast tumors. Impact: Neighborhood attributes may affect treatment and outcomes of patients with DCIS.