Rural-urban differences in secular trends of locoregional treatment for ductal carcinoma in situ: A patterns of care analysis

Abstract

Precis: Omission of PORT following BCS remains high among rural patients despite evidence that PORT leads to a significant reduction in the risk of local recurrence. Further research is needed to examine the impact of rural residence on treatment choices and develop methods to ensure equitable care among all breast cancer patients.

Background: Despite national guidelines, debate exists among clinicians regarding the optimal approach to treatment for patients diagnosed with ductal carcinoma in situ (DCIS). While regional variation in practice patterns has been well documented, population-based information on rural-urban treatment differences is lacking.

Methods: Data from the SEER Patterns of Care studies were used to identify women diagnosed with histologically confirmed DCIS who underwent cancer-directed surgery in the years 1991, 1995, 2000, 2005, 2010, and 2015. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using weighted multivariable logistic regression to evaluate cancer-directed surgery and use of post-operative radiation therapy (PORT).

Results: Of the 3337 patients who met inclusion criteria, 27% underwent mastectomy, 26% underwent breast-conserving surgery (BCS) without PORT, and 47% underwent BCS with PORT. After adjustment for other covariates, there was no difference in the likelihood of receiving mastectomy between rural and urban patients (aOR = 0.65; 95% CI 0.37-1.14). However, rural residents were more likely than urban residents to have mastectomy during 1991/1995 (aOR = 1.78; 95% CI 1.09-2.91; p_interaction = 0.022). Across all diagnosis years, patients residing in rural areas were less likely to receive PORT following BCS compared to urban patients (aOR = 0.35; 95% CI 0.18-0.67).

Conclusions: Omission of PORT following BCS remains high among rural patients despite evidence that PORT leads to a significant reduction in the risk of local recurrence. Further research is needed to examine the impact of rural residence on treatment choices and develop methods to ensure equitable care among all breast cancer patients.

Keywords: breast cancer; breast-conserving surgery; ductal carcinoma in situ; mastectomy; post-operative radiation therapy; quality of care; rural.