Survival outcomes after omission of surgery for ductal carcinoma in situ.

ABSTRACT

Clinical trials of active surveillance (AS) for Ductal Carcinoma in Situ (DCIS) are underway. We sought to understand the historical management of biologically favorable DCIS and to determine the outcomes of patients who did not have immediate surgery. Using data from the NCDB from 2004 to 2017, the selected cohort included women >40 years of age, with low or intermediate grade and hormone receptor (HR) positive DCIS. AS was defined as either no surgery or surgery >12 months from diagnosis. Women in the AS group were compared to women who had immediate surgery. A Cochran-Armitage test was used to assess the trend of AS over year of diagnosis. Kaplan-Meier curves were estimated to compare overall survival (OS), stratified by age (<50, 50-64, ≥65), and Cox proportional hazard models were used to determine the effects of prognostic factors on survival distributions. 74,367 women met study inclusion criteria; 2384 (3.2%) were treated with AS. The proportion of patients in the AS cohort increased yearly, peaking in 2017 at 4.2% (p < 0.01). On multivariable analysis, increasing age (OR 1.02, p < 0.01), black race (OR 1.7, p < 0.001), and being uninsured (OR 2.2, p < 0.001) were associated with increased likelihood of AS. In women <50 years of age, OS outcomes were similar, with 10-year OS of 97.4% in the immediate surgery cohort versus 99.1% in AS cohort (p = 0.43). The proportion of patients with DCIS treated with AS has remained small but is increasing over time. AS of biologically favorable DCIS in younger, healthier women is not associated with adverse survival.