Colorectal metastasis from gastric cancer: insights from a 14-year case series at a tertiary hospital.

Background: Colorectal metastasis from gastric cancer is very rare, with existing literature limited to only a few case reports. This study was designed to investigate the clinicopathological features and prognosis of colorectal metastasis arising from gastric cancer.

Methods: Patients with colorectal metastasis from gastric cancer who underwent surgical intervention at a single tertiary hospital between January 2010 and June 2023 were included, and their clinicopathological characteristics and oncologic outcomes were analyzed.

Results: A total of 13 patients were identified and analyzed. The majority (92.3%) experienced metachronous metastasis, with a median disease-free interval of 34.5 months (range, 16-92 months). Surgical resection was performed in 10 patients (76.9%), while the remaining 3 (23.1%) underwent diverting enterostomy. Histopathology revealed that the metastatic colorectal tumors were poorly differentiated adenocarcinoma (76.9%) or signet ring cell carcinoma (23.1%). Among the 10 patients undergoing surgical resection, 5 (50.0%) achieved R0 resection, while the others had R2 resection. After a median follow-up of 11 months (range, 0-158 months), the 2-year overall survival (OS) was 18.5%. Postoperative chemotherapy was significantly associated with improved 2-year OS (26.7% 0.0%, P=0.008), and R0 resection trended toward improved 2-year OS (37.5% 12.5%, P=0.17). Notably, one patient who received R0 resection and chemotherapy survived for 158 months.

Conclusions: Colorectal metastasis from gastric cancer demonstrated unfavorable histological features and a poor OS. Nonetheless, the pursuit of R0 resection and postoperative chemotherapy appears to hold significance, suggesting a potential avenue for improved outcomes.