Prospective observational study of zinc deficiency symptoms during first-line chemotherapy for gastric and colorectal cancer.

Background: Zinc deficiency during long-term chemotherapy and its related symptoms, including skin rash, taste disorders, and oral mucositis, have not been sufficiently investigated.
Methods: This prospective observational study enrolled patients with gastric and colorectal cancer who underwent standard first-line chemotherapy. According to the Practice Guidelines for Zinc Deficiency, zinc deficiency is defined as a serum level of <60 µg/dL. Serum zinc levels were measured before and after (1, 3, and 6 months) chemotherapy, and symptoms were assessed using the Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events version 1.0. Repeated measures were analyzed using a generalized linear mixed model.
Results: Of the 61 enrolled patients, 48 who underwent standard first-line chemotherapy with fluoropyrimidine plus oxaliplatin were analyzed. Zinc deficiency was observed in 18 patients (38%) before chemotherapy. The least-squares means of serum zinc levels significantly decreased at 3 and 6 months of chemotherapy in 30 patients without zinc deficiency at the start of chemotherapy (both P<0.01) but not in 18 with zinc deficiency at the beginning. Changes in serum zinc levels during chemotherapy negatively correlated with changes in taste, rash, and itching (all P<0.04) in patients without zinc deficiency before treatment initiation.
Conclusions: Serum zinc levels decreased during chemotherapy in zinc-non-deficient patients at the beginning of chemotherapy and correlated with taste changes, skin rash, and itching. Therefore, investigating whether zinc supplementation ameliorates these symptoms is necessary.
Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jgo.amegroups.com/article/view/10.21037/jgo-23-517/coif). T.N. reports honoraria from Daiichi Sankyo Co., Ltd., Ono Pharmaceutical Co., Ltd., Bristol Myers Squibb, Eli Lilly Japan K.K., Takeda Pharmaceutical Co., Ltd., Merck Serono Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Ltd., Taiho Pharmaceutical Co., Ltd and Yakult Honsha Co., Ltd. T.K. reports honoraria from Eli Lilly Japan K.K., Chugai Pharmaceutical Co., Ltd., Bristol Myers Squibb K.K., Taiho Pharmaceutical Co., Ltd., and Ono Pharmaceutical Co., Ltd. I.H. received consulting fees from Taiho Pharmaceutical Co., Ono Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Asahi Kasei Co., Ltd., and Daiichi Sankyo Co., Ltd., and reports honoraria from Chugai Pharmaceutical Co., Takeda Pharmaceutical Co., Ltd., and Yakult Honsha Co., Ltd. The other authors have no conflicts of interest to declare.
(2023 Journal of Gastrointestinal Oncology. All rights reserved.)