Incidence and Risk Factors of Hypomagnesemia in Head and Neck Cancer Patients Treated with Cetuximab

Abstract

ABSTRACT Aim: Hypomagnesemia is an adverse event during cetuximab treatment. However, the incidence and risk factors of hypomagnesemia in head and neck cancer patients have not been clarified. The aim of this study is to identify clinical features and risk factors of hypomagnesemia caused by cetuximab-containing therapy in head and neck cancer patients. Methods: We retrospectively reviewed 113 head and neck cancer patients who received cetuximab-containing therapy from February 2012 to March 2014. Main eligibility criteria were ≥3 cetuximab administrations, no prior EGFR-directed therapy, and no prophylactic Mg supplementation. Results: Median baseline serum Mg level and number of cetuximab administrations were 2.2 mg/dl (range 1.8-2.6) and 8 (range 3-25), respectively. Overall incidence of hypomagnesemia was 46.9% (grade 1, 43.3%; grade 2, 2.6%; grade 3, 0%; grade 4, 0.8%) and differed between patients treated with bioradiation (cetuximab and radiation) and palliative chemotherapy (26% vs. 58%; p Conclusions: While prophylactic Mg supplementation is not absolutely necessary, special attention should be given to high-risk patients, namely those with low baseline Mg level, high number of cetuximab administrations, and concurrent platinum. Hypomagnesemia in high- and low- risk groups High-risk group Low-risk group (n = 53) (n = 15) p-value OR Median baseline Mg [mg/dl] (range) 2.2 (1.8, 2.6) 2.3 (1.9, 2.6) p = 0.23 - Median Δ Mg* [mg/dl] (range) -0.5 (0, -1.2) -0.3 (0, -0.8) p - Median Δ Mg %** [%] (range) -25 (0, -67) -13 (0, -31) p - Hypomagnesemia*** 66.0% 6.6% p 27.2 *Minimum Mg - Baseline Mg, **Δ Mg / Baseline Mg, ***All grades †Mann-Whitney U test, ‡Fisher's exact test. Disclosure: All authors have declared no conflicts of interest.