Clinical and neurophysiologic prospective study with time-event and long-term analysis of the chronic neurotoxicity associated with oxaliplatin in patients with colorectal cancer (CRC).

Abstract

e15150 Background: The sensitive, symmetric, chronic neurotoxicity is a frequent dose-dependent and dose-limiting secondary effect of oxaliplatin (COXALIN). Time-event and long-term studies about COXALIN and its progression after the end of treatment ( coasting) are lacking. Methods: A prospective, translational, clinical and neurophysiologic study was performed in patients (p) with CRC treated with oxaliplatin. We analyzed COXALIN during and after treatment (at the time of initial, maximum coasting, improvement and maximum improvement). We followed p every 3 months the first year and every 6 months thereafter. The NCI-CTC V3.0 sensitive and modified TNSc (without motor and autonomic skills) clinical scales and Quantitave Sensitive Test and ENG were used. Results: 41 chemo naive p with CRC were included, 22 men, median age 60 y (IA:55-73).Oxaliplatin was administrated as adjuvant treatment in 36p. FOLFOX combination was used in 40p. The median cumulative doses was 825,25 mg/m2 (IA: 697-963). The median follow-up was 21,5m (11-27). 38 p developed COXALIN at median 5,5 m (IA: 4,4-6,6) and maximum coasting at median 8,5 m (IA: 7,6-9,5); in multivariant analysis, cumulative dose at 3 months (p = 0,039; OR 2,5; p = 0,027; HR 0,5) was predictive factor and female gender (p = 0,017; OR 0,11) was protective factor. Fine fiber neuropathy was detected in 47,4% p. All p improved at median 8,7m (IA: 7,1-10,2) since COXALIN, reaching the maximum improvement at 13,4 m (IA:16,0-20,4); on multivariate analysis, the COXALIN intensity was the predictive factor (p = 0,03; HR 0,42). 76,6%p showed residual COXALIN (73,9% p subclinical/mild, 17,4% p moderated and 8,7% p severe). A high correlation was found between clinical scales and neurophysiologic studies along the study (p < 0,0001). Sensitive NCI-CTC scale was more sensible than modified TNSc to evaluate COXALIN intensity in our study. Conclusions: We confirm coasting in COXALIN which prolongs 6 months after treatment. About 80% p showed residual COXALIN in the long-term but it was subclinical or mild in most cases. Sensitive NCI-CTC 3.0 scale is a simple and reliable method for the follow-up of COXALIN.