Prognosis and chemosensitivity of non-colorectal alimentary tract cancers with microsatellite instability

Background: Data on outcomes of microsatellite instable and/or mismatch repair deficient (dMMR/MSI) digestive non-colorectal tumors are limited.Aims: To evaluate overall survival (OS) of patients with dMMR/MSI digestive non-colorectal tumor.Methods: All consecutive patients with a dMMR/MSI digestive non-colorectal tumor were included in this French retrospective multicenter study.Results: One hundred and sixteen patients were included with a mean age of 63.6 years and 32.6% with a Lynch syndrome. Most tumors were oesophago-gastric (54.3%) or small bowel (32.8%) adenocarcinomas and at a localized stage at diagnosis (86.7%). In patients with localized tumors and R0 resection, median OS was 134.0 +/- 64.2 months. Median disease-free survival (DFS) was 100.3 +/- 65.7 months. Considering oesophago-gastric tumors, median DFS was improved when chemotherapy was added to surgery (not reached versus 22.8 +/- 10.0 months, p = 0.03). In patients with advanced tumors treated by chemotherapy, median OS was 14.2 +/- 1.9 months and median progression-free survival was 7.4 +/- 1.6 months.Conclusion: dMMR/MSI digestive non-colorectal tumors are mostly diagnosed at a non-metastatic stage with a good prognosis. Advanced dMMR/MSI digestive non-colorectal tumors have a poor prognosis with standard chemotherapy.(c) 2022 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Automated summary

This French multicenter study evaluated the overall survival of patients with dMMR/MSI digestive non-colorectal tumors. The results showed that most tumors were oesophago-gastric or small bowel adenocarcinomas and were at a localized stage at diagnosis. Patients with localized tumors and R0 resection had a median overall survival of 134.0 +/- 64.2 months. Overall, dMMR/MSI digestive non-colorectal tumors have a good prognosis, but advanced tumors treated with standard chemotherapy have a poor prognosis.