Gene Expression-Based Prediction of Neoadjuvant Chemotherapy Response in Early Breast Cancer: Results of the Prospective Multicenter EXPRESSION Trial

Clin Cancer Res. 2021 Apr 15;27(8):2148-2158. doi: 10.1158/1078-0432.CCR-20-2662. Epub 2021 Feb 4.

Abstract

Purpose: Expression-based classifiers to predict pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) are not routinely used in the clinic. We aimed to build and validate a classifier for pCR after NACT.

Patients and methods: We performed a prospective multicenter study (EXPRESSION) including 114 patients treated with anthracycline/taxane-based NACT. Pretreatment core needle biopsies from 91 patients were used for gene expression analysis and classifier construction, followed by validation in five external cohorts (n = 619).

Results: A 20-gene classifier established in the EXPRESSION cohort using a Youden index-based cut-off point predicted pCR in the validation cohorts with an accuracy, AUC, negative predictive value (NPV), positive predictive value, sensitivity, and specificity of 0.811, 0.768, 0.829, 0.587, 0.216, and 0.962, respectively. Alternatively, aiming for a high NPV by defining the cut-off point for classification based on the complete responder with the lowest predicted probability of pCR in the EXPRESSION cohort led to an NPV of 0.960 upon external validation. With this extreme-low cut-off point, a recommendation to not treat with anthracycline/taxane-based NACT would be possible for 121 of 619 unselected patients (19.5%) and 112 of 322 patients with luminal breast cancer (34.8%). The analysis of the molecular subtypes showed that the identification of patients who do not achieve a pCR by the 20-gene classifier was particularly relevant in luminal breast cancer.

Conclusions: The novel 20-gene classifier reliably identifies patients who do not achieve a pCR in about one third of luminal breast cancers in both the EXPRESSION and combined validation cohorts.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Biomarkers, Tumor / genetics*
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / genetics
  • Breast Neoplasms / therapy*
  • Chemotherapy, Adjuvant / methods
  • Clinical Decision-Making / methods*
  • Datasets as Topic
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Mastectomy
  • Middle Aged
  • Neoadjuvant Therapy / methods*
  • Neoplasm Staging
  • Oligonucleotide Array Sequence Analysis
  • Patient Selection
  • Predictive Value of Tests
  • Prognosis
  • Prospective Studies
  • Treatment Outcome

Substances

  • Biomarkers, Tumor