Arjun Lakshman, Manish Modi, Gaurav Prakash, Pankaj Malhotra, Alka Khadwal, Sanjay Jain, Savita Kumari, Neelam Varma, Subhash Varma

Bortezomib-induced peripheral neuropathy (BiPN) is a dose-limiting adverse effect of bortezomib-based therapy for multiple myeloma (MM). The reporting of BiPN is variable because of the use of different neuropathy scales. Most investigators use the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE). We prospectively evaluated the incidence of BiPN in treatment-naive patients with MM receiving weekly cyclophosphamide, bortezomib, and dexamethasone (CyBorD) in 28-day cycles using 3 neuropathy scores: Total Neuropathy Score-reduced (TNSr) and -clinical (TNSc), and NCI CTCAE v4.0. Twenty-six patients received CyBorD. Twenty patients completed follow-up. The rates of occurrence of BiPN were as follows: TNSr - 55% (n = 11), TNSc - 40% (n = 8), and NCI CTCAE - 45% (n = 9). All 3 scales showed worsening after treatment (P < .01). When compared to BiPN by TNSr, sensitivities for NCI CTCAE and TNSc were 77.8% and 88.9%, respectively. Specificity was 63.3% for both NCI CTCAE and TNSc. Among 12 patients who did not have BiPN by NCI CTCAE scale, 41.7% (n = 5) and 16.7% (n = 2) patients satisfied the criteria for BiPN by TNSr and TNSc, respectively. The higher detection rate of neuropathy by TNSr and TNSc is probably due to increment in scores that are allotted for increase in anatomic extent of sensorimotor involvement, unlike the NCI CTCAE scale, which requires functional limitation for increase in grade. NCI CTCAE may be suboptimal in comparison to TNSr and TNSc in assessment of BiPN because it may miss worsening neuropathy without functional limitation.