RESUMO
BACKGROUND: Hypomagnesemia is one of the characteristic side effects of the human anti-epidermal growth factor receptor (EGFR) monoclonal antibodies, cetuximab and panitumumab. The major mechanism of anti-EGFR antibody-related hypomagnesemia is suppression of EGFR-mediated urinary Mg(2+) reabsorption in both the renal tubule the intestinal tract. Since Mg(2+) is known to affect blood Ca(2+) levels through regulation of parathyroid hormone (PTH) secretion, we investigated the correlation between Ca(2+) and Mg(2+) concentration in blood. METHODS: Between April 2012 and October 2015, blood Mg(2+) and Ca(2+) concentrations (albumin corrected value) of 22 colon cancer patients undergoing treatment with either cetuximab or panitumumab at Toyooka Public Hospital were measured simultaneously. RESULTS: Hypomagnesemia (of all Grades) was reported in 13 of 22 patients. Two patients had hypomagnesemia of severity > Grade 3. Changes in blood Mg(2+) and Ca(2+) concentration showed a significant correlation (r(2) = 0.7455), which could be expressed using the following equation, Ca(2+) concentration = 1.4268 × (Mg(2+) concentration) + 7.1126. CONCLUSION: Since the early stages of hypomagnesemia produce no characteristic clinical symptoms, it is easily overlooked until it becomes severe. The investigation results suggest that if low blood Ca(2+) concentration (mg/dL) is observed in patients administered anti-EGFR antibodies, early evaluation of blood Mg(2+) concentration (mg/dL) and prompt supportive care are required to prevent aggravation of hypomagnesemia.
RESUMO
A 60-year-old woman with Sjögren's syndrome showed recurrence of parotid mucosa-associated lymphoid tissue (MALT) lymphoma with a simultaneous increase of serum sIL-2R antigen levels 10 years after surgical treatment. Helicobacter pylori infection had been detected in the stomach since the beginning of the lymphoma. Although H. pylori was not detected in the recurrent parotid lymphoma, antibiotic therapy contributed not only to successful eradication of gastric H. pylori but also to disappearance of the recurrent lymphoma. Further studies on the mechanisms of occurrence of extragastric MALT lymphomas are needed to establish the treatment of extragastric MALT lymphomas.
