Nerve conduction, circulating osteopontin and taxane-induced neuropathy in breast cancer patients

Objective: Chemotherapy-induced peripheral neuropathy (CIPN) is a disabling complication related to taxanes. Underlying mechanisms are not completely understood and no specific treatment exists. We investigated the role of nerve conduction studies (NCS) and of serum osteopontin (OPN) measurement as a means to stratify the risk of developing taxane-induced neuropathy (TIN). Methods: We enrolled 50 women with breast cancer treated with taxanes (docetaxel or paclitaxel) in a 3-month prospective study. They were evaluated before chemotherapy (time-point T0) and followed up at 1 (T1) and 3 (T2) months with clinical examinations/scales, quality of life (QoL) questionnaires, NCS, and serum OPN dosages. Results: A reduction of sural and superficial peroneal sensory action potentials was seen at T1, with a progression at T2 (P < 0.001). In contrast, a significant impact of neuropathic symptoms on QoL only occurred at T2 (P < 0.01). OPN levels at T0 inversely correlated to axonal loss in the sural nerve (T0–T2, P < 0.01). OPN levels at T0 were lower in the intermediate and poor outcome patient subgroups, compared to the good outcome subgroup, as specifically defined (P < 0.05). Conclusion: Lower limb NCS changes occurred earlier than the detrimental effects of TIN on patients’ QoL. Low serum OPN levels before chemotherapy may represent a novel biomarker of TIN risk.