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

Ann Surg Oncol. 2018 Sep;25(9):2563-2572. doi: 10.1245/s10434-018-6469-7. Epub 2018 May 1.

Abstract

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).

Methods: This was a retrospective analysis of all women aged 50-69 years managed for ESBC (invasive or DCIS) during the period 2007-2013 within a single service, comparing treatment according to screening status. Data on demographics, detection, pathology, and treatment were derived from hospital, cancer registry, and screening service records.

Results: Overall, 622 patients were active screeners (AS) at diagnosis (569 screen-detected and 53 ICs) and 169 patients were NRS. AS cancers were smaller (17 mm vs. 26 mm, p < 0.0001), less likely to involve nodes (26% vs. 48%, p < 0.0001), and lower grade. For invasive cancer, NRS patients were more likely to be recommended for mastectomies [35% vs. 16%; risk ratio(RR) 2.2, p < 0.0001], axillary dissection (43% vs. 19%; RR 2.3, p < 0.0001), adjuvant chemotherapy (65% vs. 37%; RR 1.7, p < 0.0001), and postmastectomy radiotherapy (58% vs. 39%; RR 1.5, p = 0.04).

Conclusion: Participants in population screening diagnosed with ESBC receive substantially less-intense treatment than non-participants. Differences persist when potential overdiagnosis is taken into account; these differences should be factored into debates around mammographic screening.

MeSH terms

  • Aged
  • Axilla
  • Breast Neoplasms / diagnostic imaging*
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy*
  • Carcinoma, Ductal, Breast / diagnostic imaging*
  • Carcinoma, Ductal, Breast / secondary
  • Carcinoma, Ductal, Breast / therapy*
  • Carcinoma, Intraductal, Noninfiltrating / diagnostic imaging*
  • Carcinoma, Intraductal, Noninfiltrating / secondary
  • Carcinoma, Intraductal, Noninfiltrating / therapy*
  • Chemotherapy, Adjuvant / statistics & numerical data
  • Early Detection of Cancer*
  • Female
  • Humans
  • Lymph Node Excision / statistics & numerical data
  • Lymphatic Metastasis
  • Mammography
  • Mastectomy / statistics & numerical data
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Patient Acceptance of Health Care
  • Radiotherapy, Adjuvant / statistics & numerical data
  • Retrospective Studies
  • Tumor Burden