Comparing RCC with LCRC, RCC is different from LCRC in clinicopathological features, molecular biomarkers and prognostic factors in Japanese colorectal cancer patients. Since the proportions of molecular biomarkers of CRC in this study are different from Western CRCs, further studies are required to clarify the clinicopathological differences between Japanese CRCs and Western CRCs.

Microsatellite instability (MSI) is an important biomarker for screening for Lynch syndrome, and also of response to immune checkpoint inhibitors. The aim of this study is to create a predictive model to determine which elderly patients with colorectal cancer (CRC) should undergo MSI and/or immunohistochemistry testing on the basis of clinicopathological data. We analyzed a test cohort of CRC patients aged ≥50 years (n = 2219) by multivariate logistic regression analyses to identify predictors of high‐frequency MSI (MSI‐H). The created prediction model was validated in an external cohort (n = 992). The frequency of MSI‐H was 5.5% among CRC patients aged ≥ 50 years. The following five predictors of MSI‐H were identified in the test cohort: female (1 point), mucinous component (2 points), tumor size ≥ 60 mm (2 points), location in proximal colon (3 points), and BRAF mutation (6 points). The area under curve (AUC) in the receiver‐operating characteristic (ROC) analysis of this prediction model was 0.832 (95% confidence interval: 0.790–0.874). The sensitivity and specificity were 74.4% and 77.7%, respectively, for a cut‐off score of 4 points. The receiver‐operating characteristic curve of the validation cohort also showed an AUC of 0.856 (95% CI: 0.806–0.905). This prediction model is useful to select elderly CRC patients who should undergo MSI testing, and who may benefit from treatment with 5‐FU‐based adjuvant chemotherapy and cancer immunotherapy.

Background The Japanese Society of Hepato‐Biliary‐Pancreatic Surgery (JSHBPS) nomogram was developed to predict disease‐free survival in patients with colorectal liver metastases (CRLM) undergoing upfront hepatectomy. However, the utility of the nomogram in patients with resected CRLM remains unknown in the current situation in which treatment strategies are changing with advances in drugs. Methods Patients in the initial nomogram cohort (n = 727) and validation cohort (n = 2225) were divided into the upfront hepatectomy and preoperative chemotherapy groups. The nomogram was validated by measuring calibration and discrimination in the two cohorts. Calibration curves were plotted, and survival probabilities were compared. Finally, to quantify the discrimination power, we estimated the concordance index (C‐index). Results In the upfront hepatectomy group, the C‐index was 0.63, the suitable cutoff value of the Beppu score was 7, and adjuvant chemotherapy was significantly effective limited to high‐risk patients (Beppu score ≥7). The C‐index was 0.56 in the preoperative chemotherapy group. Conclusions The JSHBPS nomogram remains beneficial for patients undergoing upfront hepatectomy in the recent era but is less effective for patients undergoing hepatectomy after chemotherapy. Patients with a Beppu score ≥7 showed high‐risk recurrence, and adjuvant chemotherapy should be recommended for these patients.

Background/Purpose: The purpose of the present study was to assess long-term outcomes following liver resection for colorectal liver metastases (CRLM) with concurrent extrahepatic disease and to identify the preoperative prognostic factors for selection of operative candidates. Methods: In this retrospective, multi-institutional study, 3820 patients diagnosed with CRLM during 2005-2007 were identified using nationwide survey data. Data of identified patients with concurrent extrahepatic lesions were analyzed to estimate | 811 SAWADA et Al.

Objective:BRAF D594G mutations in colorectal cancer patients are not clearly understood. We retrospectively investigated the clinicopathological features of colorectal cancers with BRAF D594G mutations. Methods: We selected 908 colorectal cancer patients who underwent surgical resection from January 2008 to January 2013, and assessed BRAF, KRAS, microsatellite instability, and CpG island methylator phenotype (CIMP). Results: We detected BRAF D594G in 7 patients and BRAF V600E in 45 patients. The clinicopathological features of cancers with BRAF D594G mutation were similar to those with BRAF wild-type, but differed from those with BRAF V600E mutations. Regarding microsatellite instability status, 44.4% of cases with BRAF V600E mutations exhibited high microsatellite instability, compared to 14.3% of those with BRAF D594G mutations and 4.4% of those with BRAF wild-type. There were no CIMP-positive tumors in cancers with BRAF D594G mutations, whereas 67.8% of tumors with BRAF V600E mutations were CIMP-positive. In stage IV cancers, the survival rates of patients at 2 years were 8.5, 50.0, and 68.2% in the BRAF V600E mutation, BRAF D594G mutation, and BRAF wild-type groups, respectively. Conclusion: Colorectal cancers with BRAF D594G mutations exhibit similar clinicopathological features, microsatellite instability status, and prognosis as those with BRAF wild-type.