Dietary Magnesium Replacement for Prevention of Hypomagnesemia in Patients With Ovarian Cancer Receiving Carboplatin-Based Chemotherapy

Abstract

PURPOSE Hypomagnesemia is a common side effect of platinum-based chemotherapy and predicts poor overall survival in some cancers. Standard magnesium replacement strategies are often inadequate for maintaining magnesium levels. We hypothesized that a daily dietary magnesium replacement approach through magnesium-rich foods would help maintain adequate magnesium levels during platinum-based treatment. MATERIALS AND METHODS We conducted a prospective feasibility study of magnesium-rich diets in patients 18 years and older with previously untreated ovarian cancer scheduled to receive carboplatin-containing chemotherapy of at least six consecutive cycles. Education about magnesium-rich diets was provided at enrollment and then weekly during chemotherapy. Feasibility was defined as ≥60% completion of dietary recalls and ≥280 mg average daily dietary magnesium intake across all patients. RESULTS Twenty-one of 26 patients enrolled completed at least five chemotherapy cycles and were included in the analysis. Adherence to the study diet was 76%. Daily dietary magnesium intake was 100.5 mg at baseline and increased throughout each cycle: 6% of patients at baseline, 24% after the first cycle, and 67% after the fifth cycle reached ≥280-mg/day magnesium intake. Seven (33%) of 21 had at least one incident of hypomagnesemia. Patients who were adherent had significantly lower incidence of hypomagnesemia (19% v 80%, P = .03) and less need for intravenous magnesium (6% v 60%, P = .03) than those who were nonadherent. CONCLUSION The study achieved primary feasibility objectives of retention and adherence to the study intervention. Weekly education about magnesium-rich diets was effective in increasing dietary magnesium intake. Adequate dietary magnesium appeared to be protective against hypomagnesemia.