The neutrophil‑to‑lymphocyte ratio (NLR) has been reported to be an independent prognostic factor of unresectable advanced or metastatic colorectal cancer (uCRC). However, few studies have documented changes in NLR during chemotherapy. The current study analyzed whether a change in NLR during chemotherapy in patients with uCRC could be used as a prognostic biomarker. The present retrospective study enrolled 71 patients who received first‑line chemotherapy for uCRC between April 2012 and April 2019. The exclusion criteria were as follows: Acute infection or systemic inflammatory disease, duration of first‑line chemotherapy <3 months, curative resection after chemotherapy and treatment with granulocyte‑colony stimulating factor within 1 month. NLR, Lymphocyte‑to‑monocyte ratio (LMR), platelet‑to‑­lymphocyte ratio (PLR), lactate dehydrogenase, alkaline phosphatase (ALP), albumin, carcinoembryonic antigen (CEA) and carbohydrate antigen 19‑9 (CA19‑9) levels were calculated before chemotherapy and at 3 months after chemotherapy. Among these laboratory data, NLR, PLR, ALP, CEA and CA19‑9 levels were significantly decreased during chemotherapy. For Cox univariate analyses, these five data makers were divided into two groups: Decreased and increased (comparing before and at 3 months after chemotherapy). Only the change in NLR was significantly associated with overall survival (P=0.0002). Furthermore, the overall survival (P<0.0001) and progression‑free survival (P=0.0041) of patients with decreased NLR was increased compared with patients with increased NLR. The change in NLR from pre‑chemotherapy to 3 months following chemotherapy was determined to be a predictor of prognosis in patients with uCRC. The ability to predict prognosis at an early phase of chemotherapy may provide useful information for the selection of subsequent treatment and may improve the quality of patient life.

Purpose: Advances in endoscopic technology have led to the reevaluation of self-expandable metallic stent (SEMS) placement as a bridge-to-surgery (BTS) in patients with obstructive colorectal cancer. In Japan, after inclusion of SEMS placement as a BTS in the medical insurance coverage in 2012, this procedure has been increasingly performed. However, a transanal decompression tube (TADT) placement has been used as a BTS. We aimed to retrospectively evaluate the optimal strategy for obstructive left-sided colorectal cancer (OLCRC) by comparing SEMS and TADT placement with emergency surgery. Methods: We included 301 patients with stage II and III OLCRC from 27 institutions. The study patients were divided into Surgery group (emergency surgery, n = 103), SEMS group (BTS by SEMS, n = 113), and TADT group (BTS by TADT, n = 85). We compared the survival and perioperative outcomes of patients in the Surgery group as a standard treatment with those in the SEMS and TADT groups. Results: The 3-year relapse-free survival rate in patients in the Surgery group was 74.8%, while that in patients in the SEMS group and TADT group were 69.0% (p = 0.39) and 55.3% (p = 0.006), respectively. The technical success rate was not statistically different, but the clinical success rate was significantly higher in the SEMS group than in the TADT group (p = 0.0040). With regard to postoperative complications after curative surgery, the SEMS group had significantly lower of complications (≥ grade 2) than the Surgery group (p = 0.022). Conclusion: Patients who underwent SEMS placement for OLCRC had similar oncological outcomes to patients who underwent emergency surgery.

The aim of this study was to investigate exfoliated cancer cells (ECCs) on linear stapler cartridges used for anastomotic sites in colon cancer. We prospectively analyzed ECCs on linear stapler cartridges used for anastomosis in 100 colon cancer patients who underwent colectomy. Having completed the functional end-to-end anastomosis, the linear stapler cartridges were irrigated with saline, which was collected for cytological examination and cytological diagnoses were made by board-certified pathologists based on Papanicolaou staining. The detection rate of ECCs on the linear stapler cartridges was 20 %. Positive detection of ECCs was significantly associated with depth of tumor invasion (p = 0.012) and preoperative bowel preparation (p = 0.003). There were no marked differences between ECC-positive and ECC-negative groups in terms of the operation methods, tumor location, histopathological classification, and surgical margins. Since ECCs were identified on the cartridge of the linear stapler used for anastomosis, preoperative mechanical bowel preparation using polyethylene glycol solution and cleansing at anastomotic sites using tumoricidal agents before anastomosis may be necessary to decrease ECCs in advanced colon cancer.

Computed tomography (CT) colonography is increasingly recognized as a valuable modality for diagnosing colorectal lesions, however, the interpretation workload remains challenging for physicians. Deep learning-based artificial intelligence (AI) algorithms have been employed for imaging diagnoses. In this study, we examined the sensitivity of neoplastic lesions in CT colonography images. Lesion location and size were evaluated during colonoscopy and a large-scale database including a dataset for AI learning and external validation was created. The DICOM data used as training data and internal validation data (total 453 patients) for this study were colorectal cancer screening test data from two multicenter joint trial conducted in Japan and data from two institutions. External validation data (137 patients) were from other two institutions. Lesions were categorized into ≥6 mm, 6 to 10 mm, and ≥10 mm. During this study, we adopted a neural network structure that was designed based on the faster R-CNNs to detect colorectal lesion. The sensitivity of detecting colorectal lesions was verified when one and two positions were integrated. Internal validation yielded sensitivity of 0.815, 0.738, and 0.883 for lesions ≥6 mm, 6 to 10 mm, and ≥10 mm, respectively, with a false lesion limit of three. Two external validation produced rates of 0.705 and 0.707, 0.575 and 0.573, and 0.760 and 0.779 for each lesion category. Combining two positions for each patient in calculating the sensitivity resulted in significantly improved rates for each lesion category. The sensitivity of CT colonography images using the AI algorithm was improved by integrating evaluations in two positions. Validation experiments involving radiologists who can interpret images as well as AI to determine the auxiliary diagnosis can reduce the workload of physicians.

Background: Recently, there has been a significant increase in the utilization of self-expandable metallic stents (SEMSs) for treating malignant colorectal obstructions through colorectal stenting. The mechanical properties of SEMSs are usually considered to affect clinical outcomes of patients with malignant colorectal obstructions. Methods: This single-arm, prospective, multicenter study of SEMS with a lower axial force and high axial force zero-border included 200 patients with malignant colorectal obstruction. Technical and clinical success, stent patency, and adverse events associated with SEMS placement were evaluated. Results: One patient was excluded, and 199 patients were evaluated. The treatment intent was bridge-to-surgery in 129 and palliation in 70 patients. Technical and clinical success rates were 99.5% and 97.0%, respectively. The percentage of the ColoRectal Obstruction Scoring System scores of 3 or higher improved significantly from 19.2% before placement to 93.9% after placement. Clinical success was not achieved in five patients due to insufficient stent expansion in four patients and stent occlusion in one patient. Only one patient underwent emergency surgery for perforation of the proximal colon, far from where the stent was placed; the rescue procedure was not performed, despite no improvement in proximal dilatation due to insufficient stent expansion. Among the palliation cohort, 15 patients received chemotherapy, including molecular-targeted agents such as bevacizumab. There were no fatal cases related to stent placement. Conclusions: For management of malignant colorectal obstruction, this newly developed SEMS with low axial force and a high axial force zero-border showed high technical and clinical success rates, and an extremely low perforation rate (0.5%).