Oral Vitamin B12 versus Placebo for the Prevention of Chemotherapy-Induced Peripheral Neuropathy in Gynecological Cancer Patients: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE: To evaluate the efficacy of vitamin B12 (cyanocobalamin) in preventing chemotherapy-induced peripheral neuropathy (CIPN) in patients with gynecological cancer who are receiving neurotoxic chemotherapy. MATERIALS AND METHODS: This randomized, double-blind, placebo-controlled study enrolled gynecological cancer patients undergoing chemotherapy at Rajavithi Hospital between January and September 2021. Patients were assigned in a 1:1 ratio to receive either vitamin B12 (500 micrograms) or a placebo, administered as two oral tablets twice daily from the start of chemotherapy until four weeks after completing six cycles. Primary endpoints included the incidence of CIPN, measured by the Patient Neurotoxicity Questionnaire (PNQ) score, and quality of life, assessed by the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) at four time points: (i) before the first chemotherapy cycle, (ii) before the third cycle, (iii) before the sixth cycle, and (iv) four weeks after completion. Safety was evaluated by monitoring vitamin B12-related adverse events. RESULTS: Forty patients were randomized into either the vitamin B12 group (n = 20) or the placebo group (n = 20). Chemotherapy regimens included taxane-based combinations with either carboplatin (87.5%) or cisplatin (12.5%). The incidence of CIPN (PNQ score ≥ 4) was significantly lower in the vitamin B12 group than in the placebo group (5% vs. 20%, p = 0.008; OR 0.21, 95% CI: 0.07-0.66). No significant differences in FACT/GOG-Ntx scores or adverse effects were observed (p > 0.05). CONCLUSION: This study highlights the significant effect of vitamin B12 in reducing the incidence of CIPN among gynecological cancer patients undergoing neurotoxic chemotherapy, with a favorable safety profile. Therefore, vitamin B12 may be recommended as a preventive measure for CIPN in this context.