PT - JOURNAL ARTICLE AU - KENJI FUJIYOSHI AU - GOU YAMAMOTO AU - TAKASHI TAKENOYA AU - AKEMI TAKAHASHI AU - YOSHIKO ARAI AU - MINA YAMADA AU - MIHO KAKUTA AU - KENSEI YAMAGUCHI AU - YOSHITO AKAGI AU - YOJI NISHIMURA AU - HIROHIKO SAKAMOTO AU - KIWAMU AKAGI TI - Metastatic Pattern of Stage IV Colorectal Cancer with High-Frequency Microsatellite Instability as a Prognostic Factor DP - 2017 Jan 01 TA - Anticancer Research PG - 239--247 VI - 37 IP - 1 4099 - http://ar.iiarjournals.org/content/37/1/239.short 4100 - http://ar.iiarjournals.org/content/37/1/239.full SO - Anticancer Res2017 Jan 01; 37 AB - Background: A recent clinical trial on the immune check-point inhibitor pembrolizumab demonstrated that microsatellite instability (MSI) is a good biomarker for response to this inhibitor. However, clinicopathological features of advanced colorectal cancer (CRC) with high-frequency MSI (MSI-H) are unclear. Patients and Methods: A total of 2,439 surgically resected CRC tissues were analyzed for MSI status, and mutational status of V-Ki-Ras2 Kirsten rat sarcoma 2 viral oncogene homolog (KRAS), neuroblastoma RAS viral oncogene homolog (NRAS) and v-Raf murine sarcoma viral oncogene homolog B (BRAF). Stage IV cases were selected, and clinical and molecular features were evaluated. Results: There was no significant survival difference observed between MSI-H CRC and microsatellite-stable (MSS) CRC in patients with stage IV disease (3.92 vs. 2.50 years; p=0.766). However, hematogenous and lymphogenous metastasis-dominant CRC with MSI-H demonstrated poor prognosis, whereas peritoneal metastasis-dominant CRC with MSI-H demonstrated good prognosis, (1.33 vs. 5.2 years; p=0.006). Conclusion: Prognosis of stage IV CRC with MSI-H depended on the metastatic pattern. These findings provide useful information for the adaptation of CRC immunotherapy.