Background Complete mesocolic excision (CME) with central vascular ligation (CVL) for colon cancer is an essential procedure for improved oncologic outcomes after surgery. Laparoscopic surgery for splenic flexure colon cancer was recently adopted due to a greater understanding of surgical anatomy and improvements in surgical techniques and innovative surgical devices. Methods We retrospectively analyzed the data of patients with splenic flexure colon cancer who underwent laparoscopic CME with CVL at our institution between January 2005 and December 2017. Results Forty-five patients (4.8%) were enrolled in this study. Laparoscopic CME with CVL was successfully performed in all patients. The median operative time was 178 min, and the median estimated blood loss was 20 g. Perioperative complications developed in 6 patients (13.3%). The median postoperative hospital stay was 9 days. According to the pathological report, the median number of harvested lymph nodes was 15, and lymph node metastasis developed in 14 patients (31.1%). No metastasis was observed at the root of the middle colic artery or the inferior mesenteric artery. The median follow-up period was 49 months. The cumulative 5-year overall survival and disease-free survival rates were 85.9% and 84.7%, respectively. The cancer-specific survival rate in stage I-III patients was 92.7%. Recurrence was observed in 5 patients (11.1%), including three patients with peritoneal dissemination and two patients with distant metastasis. Conclusions Laparoscopic CME with CVL for splenic flexure colon cancer appears to be oncologically safe and feasible based on the short- and long-term outcomes in our study. However, it is careful to introduce this procedure to necessitate the anatomical understandings and surgeon’s skill. The appropriate indications must be established with more case registries because our experience is limited.

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Background The Biocartis Idylla™ platform is a fully automated, real-time PCR-based diagnostic system. The Idylla™KRAS and NRAS-BRAF Mutation Tests have been developed for the qualitative detection of mutations in KRAS, NRAS and BRAF genes, facilitating the genomic profiling of patients with colorectal cancer. The aim of the present study was to evaluate clinical performances of these tests in Japan. Methods The RAS and BRAF mutation statuses of 253 formalin-fixed paraffin-embedded (FFPE) colorectal cancer tissues were analyzed using the Investigational Use Only Idylla™KRAS Mutation Test and the Idylla™NRAS-BRAF Mutation Test and an in vitro diagnostics (IVD) kit (MEBGEN RASKET™-B kit). Results The success rate for obtaining a valid mutational data without retest of the Idylla tests was 97.6% (247/253): 111 KRAS mutations (43.8%), 9 NRAS mutations (3.6%), and 36 BRAF V600E mutations (14.2%) were detected using the Idylla tests. Compared with the MEBGEN RASKET-B results, the positive concordance rate was 97.4%, the negative concordance rate was 95.7%, and the overall concordance rate was 95.3% (κ = 0.919, 95% CI 0.871–0.967). The average turnaround time to Idylla™KRAS and NRAS-BRAF Mutation Test was 5.6 working days (range: 3–11 days). Conclusion This result demonstrates a high concordance between the Idylla™KRAS and NRAS-BRAF Mutation Tests and an existing IVD kit. In this manner, the Idylla™ mutation tests were validated for the detection of clinically significant KRAS, NRAS, and BRAF mutations in FFPE samples from colorectal cancer patients.

Matrix metalloproteinase 14 (MMP14) expression is implicated in progression of colorectal cancer, but its role in the tumor microenvironment (TME) has been unclear. The relevance of MMP14 to colorectal cancer progression was explored by analysis of transcriptomic data for colorectal adenocarcinoma patients (n = 592) in The Cancer Genome Atlas. The role of MMP14 in the TME was investigated in a retrospective analysis of tumor samples from 86 individuals with stage III colorectal cancer by single cell–based spatial profiling of MMP14 expression as performed by 12-color multiplex immunohistochemistry (mIHC). Analysis of gene expression data revealed that high MMP14 expression was associated with tumor progression and implicated both cancer-associated fibroblasts (CAFs) and tumor-associated macrophages in such progression. Spatial profiling by mIHC revealed that a higher percentage of MMP14+ cells among intratumoral CAFs (MMP14+ CAF/CAF ratio) was associated with poorer relapse-free survival. Multivariable analysis including key clinical factors identified the MMP14+ CAF/CAF ratio as an independent poor prognostic factor. Moreover, the patient subset with both a high MMP14+ CAF/CAF ratio and a low tumor-infiltrating lymphocyte density showed the worst prognosis. Our results suggest that MMP14+ CAFs play an important role in progression of stage III colorectal cancer and may therefore be a promising therapeutic target.