The prognostic value of the neoadjuvant response index in triple-negative breast cancer: validation and comparison with pathological complete response as outcome measure

Abstract

The Neoadjuvant response index (NRI) has been proposed as a simple measure of downstaging by neoadjuvant treatment in breast cancer. It was previously found to predict recurrence-free survival (RFS) in triple-negative (TN) breast cancer. It was at least as accurate as the standard binary system, the absence or presence of a pathological complete remission (pCR), which is the commonly employed outcome measure. The NRI was evaluated in an independent consecutive series of patients to validate the previous findings. Univariable and multivariable analyses were done to assess the predictive value of clinical parameters and of the NRI for RFS. We combined the original and validation series of patients to build a multivariable predictive model for RFS after neoadjuvant chemotherapy in TN breast cancer. The validation set (N = 108) confirmed that patients with a higher-than-median NRI (>0.7) had excellent RFS (P = 0.002), similar to that of patients who had achieved a pCR. Multivariable analysis in 191 patients showed that the NRI was a strong independent predictor of RFS (P = 0.0002), with N-stage (P = 0.001) and T-stage (P = 0.014) ranking second and third, respectively. Importantly, among patients who did not achieve a pCR (NRI values below 1), higher NRI values were still associated with better RFS. The NRI is a simple method and a practical tool to predict RFS in TN breast cancer patients treated with neoadjuvant chemotherapy. It adds prognostic information to the presence or absence of pCR and could be useful to compare the efficacies of different chemotherapy regimens.

Comprehensive characterization of pre- and post-treatment samples of breast cancer reveal potential mechanisms of chemotherapy resistance

“…The Neoadjuvant Response Index (NRI), an alternative, semi-continuous measure of response 8 , was determined for 253 patients and could be used to further assess therapy response in patients who did not achieve a pCR. As described previously 16 , NRI was significantly associated with recurrence free survival in TN patients ( p = 0.0003, HR = 0.12 (95% CI: 0.038–0.379)). NRI was significantly different between ER+ and TN patients (median NRI 0.29 versus 0.67 for ER+ and TN tumors, respectively, p = 2.61e−16).…”

High-dose alkylating chemotherapy in BRCA-altered triple-negative breast cancer: the randomized phase III NeoTN trial

“…Interestingly, although not statistically significant, a difference in 4-year RFS was found (78% [95% CI 68–89%] vs 90% [95% CI 83–98%]), between conventional and high-dose chemotherapy. Of note, as shown previously in other cohorts 11 , 12 , this study finds that the NRI is strongly predictive for RFS even when excluding cases who achieve pCR (NRI = 1), indicating prognostic value beyond that of pCR.…”

Neoadjuvant Bevacizumab plus Chemotherapy versus Chemotherapy Alone to Treat Non-Metastatic Breast Cancer: A Meta-Analysis of Randomised Controlled Trials

“…There is also other evidence to suggest that ER-negative tumours tend to have a higher pCR than ER-positive tumours in response to chemotherapy [ 31 – 33 ]. This is of great clinical importance in that the prognosis of patients with TNBC is relatively poor, as conventional chemotherapy remains the only available systemic treatment option [ 34 ]. Recent studies confirmed the result that the pCR was higher for the TNBC subtype, further indicating that a higher pCR strongly predicted improved survival in this subtype.…”