Analysis of Factors Influencing the Tolerability of S-1 plus Oxaliplatin in Patients with Advanced Gastric Cancer

Abstract

Oxaliplatin (L-OHP) was approved for the treatment of gastric cancer in 2015 in Japan. Cisplatin (CDDP) and L-OHP are used as the first-line therapy for unresectable advanced or recurrent gastric cancer. Compared with CDDP, L-OHP has fewer adverse effects such as nausea and vomiting. Moreover, L-OHP does not need a large amount of hydration. Many outpatients with gastric cancer can use L-OHP. L-OHP is used with S-1 (SOX) for unresectable advanced or recurrent gastric cancer. However, some patients need to take a reduced dose or discontinue therapy. Thus, we evaluated the factors that influence the tolerance to SOX, to improve treatment safety and predict adverse events. The study included 22 patients who were treated with SOX. Intolerant patients were defined as those who required a reduced dose or discontinuation of therapy. Eight patients were defined as intolerant. The factors that influenced tolerance included surgical history of gastric cancer (P = 0.018), body mass index < 18.5 (P = 0.039), low neutrophil count (P = 0.039), low platelet count (P = 0.039), and high aspartate transaminase level (P = 0.036). All intolerant patients underwent surgery for gastric cancer. The duration from surgery to the initiation of SOX in intolerant patients was shorter than that for tolerant patients (P = 0.021). In conclusion, the factors that influence tolerance in patients receiving SOX were short duration from surgery to SOX, low body mass index, low neutrophil count, low platelet count and high aspartate transaminase level. Therefore, patients who have these factors require careful monitoring for adverse events.