Case report: surgery combined with a SOX adjuvant chemotherapy regimen for patients with gastric adenocarcinoma and hepatocellular carcinoma.

Advances in early tumor detection have led to an increase in the reported incidence of multiple primary cancers. However, the concurrent occurrence of gastric adenocarcinoma and hepatocellular carcinoma remains rare. We present the case of a 68-year-old male patient with chronic hepatitis B who was diagnosed with stage Ib liver cancer (T1bN0M0). Gastroscopy revealed a mucosal lesion in the posterior wall of the gastric body, and biopsy confirmed moderately to poorly differentiated adenocarcinoma. The patient underwent laparoscopic gastrectomy combined with partial liver resection, followed by three cycles of S-1 plus oxaliplatin (SOX) chemotherapy. Given the lack of standardized treatment protocols for managing multiple primary cancers, developing a treatment plan for these two synchronous cancers is challenging. This case underscores the importance of early screening for multiple primary cancers and the need for a multidisciplinary approach to formulate an optimal treatment strategy. Furthermore, we conducted a literature review of reports on the simultaneous occurrence of gastric and hepatic cancers over recent decades. Unlike previous studies, we also examined postoperative adjuvant chemotherapy regimens suitable for both gastric adenocarcinoma and hepatocellular carcinoma patients.