The significance of dorsal sural nerve recordings in early detecting oxaliplatin-induced peripheral neuropathy

INTRODUCTION: Thus far, there is no gold standard for the accurate monitoring of Oxaliplatin-induced peripheral neuropathy (OXAIPN). For anatomical reasons, Dorsal Sural Nerve (DSN) conduction study might be able to predict the neurological outcome at end of chemotherapy. Our objective was to assess its ability to early detect OXAIPN. METHODS: A total of 116 colorectal cancer patients [75 (64,6%) male, 41 (35,4%) female, median age of 64 years; range: 38-77 y.o.] were evaluated before, at middle-point and at the end of chemotherapy. Standard nerve conduction studies plus DSN were performed. The Total Neuropathy Score–clinical version (TNSc) was used to assess OXAIPN. Elaborating a tree regression, cut-offs for z-score of DSN amplitude were individuated to subdivide at mid-treatment subjects at high versus low risk to develop neurotoxicity at the end of chemotherapy. RESULTS: At baseline all patients had no preexisting neuropathy. At mid-treatment, 11 (9,5%) patients had abnormal sural nerve amplitudes and 24 (20,7%) abnormal DSN amplitudes. At the end of treatment, 37 (32%) patients had grade I neuropathy and 37 (32%) had grade II/III. Forty-four (38%) patients had abnormal sural nerve amplitudes and 55 (47,4%) had abnormal DSN amplitudes. The -0.815 cut-off for the z-score of DSN amplitude was able to individuate the probability of patients to develop OXAIPN, better than sensory nerves conventionally studied, e.g., sural nerve. CONCLUSIONS: DSN recording might be a useful objective outcome measure to individuate patients at higher risk to develop neurotoxicity during chemotherapy. It might also be a significant end-point in neuroprotection trials.