Postmastectomy radiation ups survival in T1-2 TNBC with 1-3 positive nodes

  • Zhang J & al.
  • Oncotarget
  • 27 Aug 2019

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • Postmastectomy radiotherapy (PMRT) boosts OS in patients with triple-negative breast cancer (TNBC) with T1-2 tumors and 1-3 positive lymph nodes (N1-3).

Why this matters

  • PMRT is standard of care for patients with ≥4 axillary lymph nodes, but use in N1-3 disease remains controversial. 
  • Findings are strong enough to warrant a prospective study.

Study design

  • Population-based retrospective cohort of 675 patients with T1-2, N1-3 TNBC in the Surveillance, Epidemiology, and End Results database, 2010-2012.
  • 312 underwent PMRT and 363 did not.
  • Funding: National Natural Science Foundation of China; the Wu Jieping Medical Foundation.

Key results

  • Median follow-up, 37 months.
  • Kaplan-Meier analysis: PMRT improved OS (P=.033), but not breast cancer-specific survival (BCSS; P=.063).
  • Multivariate Cox proportional hazards model: PMRT improved OS (HR, 0.661; P=.025) and BCSS (HR, 0.664; P=.039).
  • No significant differences in OS or BCSS were found in either analysis when stratified by the number of positive lymph nodes.

Limitations

  • Observational, retrospective design.
  • No data on locoregional recurrence.