Peripheral neuropathy exacerbated by lenalidomide in a patient with multiple myeloma

We evaluated a serial change in peripheral neuropathy (PN) severity during treatment with bortezomib (Bor) or lenalidomide (Len) using the Functional Assessment of Cancer Therapy scale/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx). The patient suffered from grade 2 PN and exhibited a dramatic decrease in FACT/GOG-Ntx score after intravenous and subcutaneous Bor therapy. Thereafter, he received seven cycles of Len therapy, which exacerbated existing PN; he experienced mild numbness and exhibited a transient decrease in FACT/GOG-Ntx score. Interestingly, FACT/GOG-Ntx score increased to baseline and numbness was ameliorated during the Len washout period in every cycle.