PITFALLS IN GRADING SEVERITY OF CHEMOTHERAPY-INDUCED PERIPHERAL NEUROPATHY

Background: Reliable reporting of chemotherapy-induced neurotoxicity i s important. The objectives of the current study were to evaluate the differences in the peripheral neurotoxicity sections of several widely used chemotherapy-related toxicity grading systems, and the differenc es in the way in which observers interpret these scales. Patients and methods. Two neurologists independently rated the severity of chemothe rapy-induced peripheral neuropathy, according to WHO, ECOG, Ajani, and NCIC-CTC criteria in 37 patients. Results: The highest percentage gra de 1, grade 2 and grade 3 peripheral neurotoxicity was noted when empl oying the WHO, Ajani and NCIC-CTC scales, respectively. Percentage int erobserver agreement across all grades of severity ranged from 45.9 (N CIC-CTC) to 83.5 (WHO). The degree of agreement varied from 'poor to f air' to 'substantial'. Percentage interobserver agreement for the dich otomy grade less than or equal to 2 and grade 3 ranged from 81.1 (NCIC -CTC) to 94.6 (Ajani and WHO), however, exact agreement on grade 3 per ipheral neurotoxicity ranged from 0 (Ajani and WHO) to 42% (NCIC-CTC). Percentage interscale agreement for the dichotomy grade less than or equal to 2 and grade 3 varied from 67.6 (WHO and NCIC-CTC) to 100 (WHO and ECOG). Interobserver disagreement of severity grading was partly due to different interpretation of scale parameters. Conclusions: Our results suggest that caution should be used in interpreting results ac ross studies using different scales for neurotoxicity grading in chemo therapy-related peripheral neuropathy. When (multicentre) trials are t o be undertaken with potential neurotoxic or neuroprotective agents, c onsensus should be sought regarding the toxicity rating scale used, an d its interpretation by participating physicians.