Affiliation: | 1. General Surgery and Surgical Oncology Department, University of Siena, Italy viale Bracci 16, 53100, Siena, Italy;2. Department of Surgical Oncology, Medical University of Gdansk, Gdansk, Poland;3. Department of Pathology, Christian-Albrechts-University, Kiel, Germany;4. Department of Gastrointestinal Oncology and Lymphoma, Royal Marsden Hospital, London and Sutton, United Kingdom;5. General, Minimally Invasive and Robotic Surgery, Department of Surgery, “San Matteo degli Infermi Hospital”–ASL Umbria 2, 06049, Spoleto, Italy;6. Department of General, Visceral, Thoracic, Transplant and Pediatric Surgery, Christian-Albrechts-University, Kiel, Germany;g. University Cancer Center Leipzig (UCCL), University Medicine Leipzig, 04103 Leipzig, Germany |
Abstract: | BackgroundCurrent guidelines recommend that metastatic gastric cancer should not be treated with surgery unless this is required for symptom control. We hypothesized that patients with mismatch repair deficiency (MMRd) gastric cancer and metastatic disease detected at the timepoint of surgical resection would have superior survival compared to patients with MMRd cancers in the same setting.MethodsClinicopathological details and survival data were collected from prospective databases at two large European centers on patients who had undergone surgery and were diagnosed with synchronous stage IV gastric cancer (distant lymph nodes, positive peritoneal cytology, peritoneal, and distant metastases) at the timepoint of surgery. Resection specimens were tested for the presence of microsatellite instability using a standard 5 mononucleotide repeat panel.ResultsOne hundred and seventy six patients with resected stage IV gastric cancer were identified. 14/176 (8.0%) had MSI-H (high) disease. There was no significant difference between the clinical and pathological characteristics of MSI and microsatellite stable (MSS) patients. No differences in the type of metastases were observed between MSI and MSS groups. Patients who were MSI-H had superior OS compared to MSS patients (median OS 15.9 vs. 8 months, p = 0.023). However, in Cox regression multivariate analysis only liver and peritoneal metastases were independent predictors of survival.ConclusionsSurgically treated patients with MSI-H stage IV gastric cancer have a better survival than patients with MSS gastric cancer. Further analysis of the role of surgery in MSI stage IV GC is required. |