Prognostic role of adjuvant radiotherapy in triple-negative breast cancer: A historical cohort study

Int J Cancer. 2015 Nov 15;137(10):2504-12. doi: 10.1002/ijc.29617. Epub 2015 Jul 14.

Abstract

The value of adjuvant radiotherapy in triple-negative breast cancer (TNBC) is currently debated. We assessed the association between adjuvant radiotherapy and survival in a large cohort of Asian women with TNBC. Women diagnosed with TNBC from 2006 to 2011 in five Asian centers (N = 1,138) were included. Survival between patients receiving mastectomy only, breast-conserving therapy (BCT, lumpectomy and adjuvant radiotherapy) and mastectomy with radiotherapy were compared, and adjusted for demography, tumor characteristics and chemotherapy types. Median age at diagnosis was 53 years (range: 23-96 years). Median tumor size at diagnosis was 2.5 cm and most patients had lymph node-negative disease. The majority of patients received adjuvant chemotherapy (n = 861, 76%) comprising predominantly anthracycline-based regimes. In 775 women with T1-2, N0-1, M0 TNBCs, 5-year relative survival ratio (RSR) was highest in patients undergoing mastectomy only (94.7%, 95% CI: 88.8-98.8%), followed by BCT (90.8%, 95% CI: 85.0-94.7%), and mastectomy with radiotherapy (82.3%, 95% CI: 73.4-88.1%). The adjusted risks of mortality between the three groups were not significantly different. In 363 patients with T3-4, N2-3, M0 TNBCs, BCT was associated with highest 5-year RSR (94.1%, 95% CI: 81.3-99.4%), followed by mastectomy with radiotherapy (62.7%, 95% CI: 54.3-70.1%), and mastectomy only (58.6%, 95% CI: 43.5-71.6%). Following multivariable adjustment, BCT and mastectomy with radiotherapy remained significantly associated with lower mortality risk compared to mastectomy only. Overall, adjuvant radiotherapy was associated with higher survival in women aged <40 years, but not in older women. Adjuvant radiotherapy appears to be independently associated with a survival gain in locally advanced as well as in very young TNBC.

Keywords: Asia; adjuvant radiotherapy; postmastectomy; survival; triple-negative breast cancer.

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents / administration & dosage*
  • Antineoplastic Agents / therapeutic use
  • Chemotherapy, Adjuvant
  • Cohort Studies
  • Female
  • Humans
  • Mastectomy / methods
  • Middle Aged
  • Radiotherapy, Adjuvant
  • Survival Analysis
  • Treatment Outcome
  • Triple Negative Breast Neoplasms / drug therapy
  • Triple Negative Breast Neoplasms / mortality*
  • Triple Negative Breast Neoplasms / radiotherapy*
  • Triple Negative Breast Neoplasms / surgery
  • Young Adult

Substances

  • Antineoplastic Agents