Prospectively assessing serum neurofilament light chain levels as a biomarker of paclitaxel‐induced peripheral neurotoxicity in breast cancer patients

Abstract Our aim was to assess the significance of measuring serum neurofilament light chain (sNfL) levels as a biomarker of paclitaxel‐induced peripheral neurotoxicity (PIPN). We longitudinally measured sNfL in breast cancer patients, scheduled to receive the 12‐weekly paclitaxel‐based regimen. Patients were clinically examined by means of the Total Neuropathy Score‐clinical version (TNSc), while sNfL were quantified, using the highly sensitive Simoa technique, before starting chemotherapy (baseline), after 2 (week 2) and 3 (week 3) weekly courses, and at the end of chemotherapy (week 12). Among 59 included patients (mean age: 53.1 ± 11.5 years), 33 (56%) developed grade 0‐1 and 26 (44%) grade 2‐3 PIPN at week 12. A significant longitudinal increase of sNfL levels from baseline to week‐12 was determined, whereas patients with TNSc grade 2‐3 PIPN had significantly increased sNfL levels at week 12, compared to those with grade 0‐1. receiver‐operated characteristics (ROC) analysis defined a value of NfL of >85 pg/mL at week 3 as the best discriminative determination to predict the development of grade 2‐3 PIPN at week 12 (sensitivity 46.2%, specificity 84.8%). The logistic binary regression analysis revealed that age > 50 years and the cutoff of >85 pg/mL of sNfL levels at week 3 independently predicted the development of grade 2‐3 PIPN at week 12 with a sensitivity of 46%, a specificity of 91%, and a positive and negative predictive values of 75% and 67%, respectively. sNfL levels seem to be a valuable biomarker of neuro‐axonal injury in PIPN. An early increase of this biomarker after a 3‐weekly chemotherapy course can be a predictive marker of final PIPN severity.