Adjuvant chemotherapy in small node-negative triple-negative breast cancer

Tessa G. Steenbruggen, Erik van Werkhoven, Mette S. van Ramshorst, Vincent O. Dezentjé, Marleen Kok, Sabine C. Linn, Sabine Siesling, Gabe S. Sonke*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background: Recommendations on adjuvant chemotherapy in pT1N0M0 triple-negative breast cancer (TNBC) differ among international guidelines owing to lack of randomized trial data. We evaluated associations of adjuvant chemotherapy with a long-term outcome in a population-based cohort of pT1N0M0 TNBC. Methods: All patients diagnosed with pT1N0M0 TNBC in the Netherlands between 2005 and 2016 were identified from the Netherlands Cancer Registry. Patient, tumour and treatment characteristics were recorded. The date and cause of death were obtained from Statistics Netherlands. We used multivariable Cox regression models to evaluate associations of adjuvant chemotherapy with breast cancer–specific survival (BCSS) and overall survival (OS), adjusted for baseline characteristics and performed sensitivity analyses using propensity score (PS) weighting. Results: We identified 4366 patients: 284 with pT1a, 923 with pT1b and 3159 with pT1c tumours. Adjuvant chemotherapy was administered in 53% of patients. Patients receiving chemotherapy had more unfavourable baseline characteristics including younger age, larger tumours and higher tumour grade. At 8.2 years median follow-up (interquartile range = 5.8–10.9), 671 patients had died, of whom 311 because of breast cancer. After adjustment for baseline characteristics, chemotherapy was associated with improved BCSS (adjusted hazard ratio [aHR] = 0.65; 95% confidence interval [CI] = 0.48–0.89). The effect of chemotherapy differed by tumour size (pT1a: aHR = 4.28, 95% CI = 1.12–16.44; pT1b: aHR = 1.12, 95% CI = 0.51–2.49; pT1c: aHR = 0.60, 95% CI = 0.43–0.82; pinteraction = 0.02). Findings for OS were in line with BCSS results. PS-weighting analysis confirmed the results of the primary analysis. Conclusions: Adjuvant chemotherapy is associated with better BCSS and OS in pT1N0M0 TNBC. Better outcome is most evident in pT1c tumours and may not outweigh harm in pT1a/pT1b tumours.

Original languageEnglish
Pages (from-to)66-74
Number of pages9
JournalEuropean journal of cancer
Volume135
Early online date14 Jun 2020
DOIs
Publication statusE-pub ahead of print/First online - 14 Jun 2020

Keywords

  • Adjuvant chemotherapy
  • Axillary lymph node–negative
  • Triple-negative breast cancer

Fingerprint Dive into the research topics of 'Adjuvant chemotherapy in small node-negative triple-negative breast cancer'. Together they form a unique fingerprint.

  • Cite this

    Steenbruggen, T. G., van Werkhoven, E., van Ramshorst, M. S., Dezentjé, V. O., Kok, M., Linn, S. C., ... Sonke, G. S. (2020). Adjuvant chemotherapy in small node-negative triple-negative breast cancer. European journal of cancer, 135, 66-74. https://doi.org/10.1016/j.ejca.2020.04.033