Treatment Intensity Differences After Early-Stage Breast Cancer (ESBC) Diagnosis Depending on Participation in a Screening Program

Background While population mammographic screening identifies early-stage breast cancers (ESBCs; ductal carcinoma in situ [DCIS] and invasive disease stages 1–3A), commentaries suggest that harms from overdiagnosis and overtreatment may outweigh the benefits. Apparent benefits to patients with screen-detected cancers may be due to selection bias from exclusion of interval cancers (ICs). Treatment intensity is rarely discussed, with an assumption that all ESBCs are treated similarly. We hypothesized that women diagnosed while in a screening program would receive less-intense treatment than those never or not recently screened (NRS).