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BackgroundIn Japan, there are no substantial reports on robotic‐assisted colectomy because few institutions performed the procedure, as it was not covered by national insurance until March 2022.AimThis study aimed to evaluate the safety and feasibility of robotic‐assisted colectomy for patients with curatively resectable colon cancer in Japan.MethodsThis multi‐institutional, prospective, single‐arm, observational study enrolled patients diagnosed with curatively resectable clinical stage I–IIIC colon adenocarcinoma with D2 or D3 lymph node dissection and treated with robotic‐assisted colectomy. The primary endpoint was the conversion rate to laparotomy. The non‐inferiority of outcomes for robotic‐assisted colectomy versus laparoscopic colectomy, which was determined from historical data, was verified.ResultsOne hundred patients were registered between July 2019 and March 2022 and underwent robotic‐assisted colectomy performed by seven expert surgeons at six institutions. Thirteen patients were excluded because their surgeons had insufficient experience performing robotic‐assisted colectomy; therefore, 87 patients were eligible for the primary endpoint analysis. There was no conversion in these 87 patients, and robotic‐assisted colectomy was non‐inferior to laparoscopic colectomy in terms of conversion rate (90% confidence interval 0–3.38, p = 0.0006). No intraoperative adverse events occurred, and no mortality was observed in a total of 100 patients. The rate of patients with Clavien–Dindo complications grade III or higher was 4%.ConclusionThis study showed the non‐inferiority of the conversion rates between robotic‐assisted colectomy and laparoscopic colectomy. Favorable perioperative outcomes also suggest the safety and feasibility of robotic‐assisted colectomy.

INTRODUCTION:The aim of this study was to evaluate the effect of biologics on the risk of advanced-stage inflammatory bowel disease (IBD)-associated intestinal cancer from a nationwide multicenter data set.METHODS:The medical records of patients with Crohn's disease (CD) and ulcerative colitis (UC) diagnosed with IBD-associated intestinal neoplasia (dysplasia or cancer) from 1983 to 2020 were included in this study. Therapeutic agents were classified into 3 types: biologics, 5-aminosalicylic acid, and immunomodulators. The pathological cancer stage was compared based on the drug used in both patients with CD and UC.RESULTS:In total, 1,042 patients (214 CD and 828 UC patients) were included. None of the drugs were significantly associated with cancer stage in the patients with CD. In the patients with UC, an advanced cancer stage was significantly associated with less use of biologics (early stage: 7.7% vs advanced stage: 2.0%, P < 0.001), 5-aminosalicylic acid, and immunomodulators. Biologic use was associated with a lower incidence of advanced-stage cancer in patients diagnosed by regular surveillance (biologics [−] 24.5% vs [+] 9.1%, P = 0.043), but this was not the case for the other drugs. Multivariate analysis showed that biologic use was significantly associated with a lower risk of advanced-stage disease (odds ratio = 0.111 [95% confidence interval, 0.034–0.356], P < 0.001).DISCUSSION:Biologic use was associated with a lower risk of advanced IBD-associated cancer in patients with UC but not with CD. The mechanism of cancer progression between UC and CD may be different and needs to be further investigated.

The outer mucus layer of the colorectal epithelium is easily removable and colonized by commensal microbiota, while the inner mucus layer is firmly attached to the epithelium and devoid of bacteria. Although the specific bacteria penetrating the inner mucus layer can contact epithelial cells and trigger cancer development, most studies ignore the degree of mucus adhesion at sampling. Therefore, we evaluated whether bacteria adhering to tissues could be identified by removing the outer mucus layer. Our 16S rRNA gene sequencing analysis of 18 surgical specimens of human colorectal cancer revealed that Sutterella (P = 0.045) and Enterobacteriaceae (P = 0.045) were significantly enriched in the mucus covering the mucosa relative to the mucosa. Rikenellaceae (P = 0.026) was significantly enriched in the mucus covering cancer tissues compared with those same cancer tissues. Ruminococcaceae (P = 0.015), Enterobacteriaceae (P = 0.030), and Erysipelotrichaceae (P = 0.028) were significantly enriched in the mucus covering the mucosa compared with the mucus covering cancers. Fusobacterium (P = 0.038) was significantly enriched in the mucus covering cancers compared with the mucus covering the mucosa. Comparing the microbiomes of mucus and tissues with mucus removed may facilitate identifying bacteria that genuinely invade tissues and affect tumorigenesis.