A sutureless overlapped anastomosis technique using linear staplers with reinforced bioabsorbable material in robotic right colectomy with intracorporeal anastomosis.

AIM: Creation of an overlapped anastomosis using handsewn sutures for common enterotomy is very popular in robotic right colectomy (RRC) with intracorpareal anastomosis (IA). The aim of this study is to present a simple method for constructing a sutureless overlapped anastomosis using a 60 mm linear stapler with a reinforced bioabsorbable material in RRC with IA. METHOD: The distal ileum and proximal colon were put in overlapping positions. Enterotomies were created 2 cm proximal to the ileal stump and 8 cm distal to the colonic stump on the antimesenteric side. Subsequently, a 60 mm linear stapler with a reinforced bioabsorbable material was inserted into each lumen and fired. Finally, the bowel was elevated while holding the bioabsorbable material, and the common enterotomy was grasped with the robotic instrument in the middle and closed using a linear stapler with a reinforced bioabsorbable material. RESULTS: This technique was applied to 10 patients with tumours of the caecum, ascending colon, or transverse colon. The median operating time, anastomosis construction time, blood loss, and postoperative stay were 281 min (range 228-459 min), 12 min (range 11-17 min), 10 mL (range 0-110 mL), and 10 days (range 8-15 days), respectively. No adverse intraoperative events were observed. Postoperatively, one patient developed chylous ascites, but there were no other complications. CONCLUSION: The simple technique for constructing a sutureless overlapped anastomosis using a 60 mm linear stapler with a reinforced bioabsorbable material in robotic right colectomy with intracorporeal anastomosis appears to be safe and feasible.

Comparative efficacy and safety of adjunctive drugs to levodopa for fluctuating Parkinson's disease - network meta-analysis.

It remains unclear which adjunctive drug for Parkinson's disease (PD) in combination with levodopa is more effective, tolerable, and safe. We aimed to compare the efficacy, tolerability, and safety among anti-PD drugs from several classes in patients with fluctuating PD who received levodopa through network meta-analysis (NMA). Twelve anti-PD drugs belonging to 4 different drug classes (dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyl transferase inhibitors, and an adenosine A2A receptor antagonist) were selected. We systematically searched PubMed, Embase, and the Cochrane Library for eligible randomized controlled trials (RCTs) comparing placebo with anti-PD drug or among anti-PD drugs in patients with PD who experienced motor fluctuations or wearing-off and received levodopa. We included 54 RCTs in the analysis. The NMA was performed under a frequentist framework using a random-effects model. The efficacy outcome was change in daily off-time, and the tolerability outcome was discontinuation due to all causes. Safety outcomes included discontinuation due to adverse events (AEs) and the incidence of AEs, dyskinesia, hallucination, and orthostatic hypotension. According to the surface under the cumulative ranking curve (SUCRA) in the NMA, ropinirole transdermal patch (SUCRA, 0.861) ranked the highest in efficacy, followed by pramipexole (0.762), ropinirole extended release (ER) (0.750), and safinamide (0.691). In terms of tolerability, ropinirole (0.954) ranked the highest, followed by pramipexole (0.857), safinamide (0.717), and ropinirole ER (0.708). Each anti-PD drug had different SUCRA ranking profiles for the safety outcomes. These findings suggest that ropinirole, pramipexole, and safinamide are well-balanced anti-PD drugs that satisfy both efficacy and tolerability outcomes.

Mucosectomy of the anal canal via transanal minimally invasive surgery combined with transanal total mesorectal excision for familial adenomatous polyposis: A technical note.

AIM: Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the standard surgical treatment modality for familial adenomatous polyposis (FAP). It is challenging to perform proctectomy and preserve anal sphincter function. In this video, precise mucosectomy of the anal canal via transanal minimally invasive surgery (MAC-TAMIS) is reported. METHODS: An asymptomatic 35-year-old man was found to have a positive faecal occult blood test in routine screening examination and was diagnosed with FAP on colonoscopic examination. The patient was scheduled for total proctocolectomy with IPAA using the TAMIS approach combined with transanal total mesorectal excision. MAC-TAMIS was performed to preserve the internal anal sphincter during laparoscopy. RESULTS: The total duration of surgery was 543 min, blood loss was minimal, and the postoperative course was uneventful. The postoperative hospital stay was 12 days. The pathological findings demonstrated no evidence of malignancy. Gastrographic imaging from the ileostomy showed sufficient size of the J pouch and good tonus of the anus at 6 months after surgery. The Wexner scores at 1, 3 and 6 months after ileostomy closure were 5, 3 and 0, respectively. CONCLUSION: The MAC-TAMIS technique is safe and feasible during total proctocolectomy with IPAA in patients with FAP. This technique allows us to precisely preserve the internal anal sphincter using a laparoscopic approach.

[A Case of Curative Resection Following TNT for Locally Advanced Rectal Cancer with Liver Metastasis].

The standard treatment of locally advanced rectal cancer is preoperative chemoradiotherapy(CRT)in Europe and the United States, while that is surgical excision and lateral pelvic lymph node dissection followed by adjuvant chemotherapy in Japan. Recently, total neoadjuvant therapy(TNT), which combines neoadjuvant chemotherapy and preoperative CRT, have been popular. We performed curative excision for initially locally advanced rectal cancer with liver metastasis after TNT. A 61- year-old woman was diagnosed as having rectal cancer with liver metastasis and invasion of the uterus, vagina, bladder, and left ureter. The patient underwent 8 courses of FOLFOX plus bevacizumab, followed by radiotherapy, and totally pelvic excision for the primary tumor. Because of liver metastasis progression, hepatectomy was performed after 6 courses of FOLFIRI plus panitumumab. The patient has been cancer free for 20 months to date. TNT is considered to be an effective strategy for the treatment of large locally advanced rectal cancer.

Vascular endothelial growth factor inhibitors promote antitumor responses via tumor microenvironment immunosuppression in advanced colorectal cancer.

PURPOSE: This study aims to investigate changes in the tumor immune environment of patients who underwent therapy with a vascular endothelial growth factor (VEGF) inhibitor for advanced colorectal cancer. METHODS: Patients (n = 135) with T3 or T4 colorectal cancer were included in this retrospective study. They were classified as follows: patients who had not received preoperative treatment (UPFRONT group, n = 54), who had received FOLFOX as preoperative chemotherapy (FOLFOX group, n = 55), and who had undergone resection after combination FOLFOX and bevacizumab as unresectable colorectal cancer (B-MAB group, n = 26). The number of cytotoxic T lymphocytes (CTLs), FOXP3+ lymphocytes (including regulatory T cells (Tregs)), CD163+ monocytes (including M2-type tumor-associated macrophages (TAM-M2 type)), and programmed cell death 1 (PD-1)+ lymphocytes was evaluated immunohistochemically in the cancer cell area (CC) and stromal cell area (ST) of surgical specimens, and compared among the three groups. RESULTS: The CTL population did not differ among the three groups in both areas. In the B-MAB group, the numbers of PD-1+ cells in the ST, FOXP3+ lymphocytes in both areas, and CD163+monocytes in the ST was lower than that in the other two groups, and a correlation with the histological therapeutic effect was observed. CONCLUSIONS: In advanced colorectal cancer, VEGF inhibitors may decrease the number of PD-1+ cells and inhibit the infiltration of FOXP3+ lymphocytes and CD163+monocytes into the tumor environment.

Molecular Pathogenesis of Colorectal Cancer: Impact of Oncogenic Targets Regulated by Tumor Suppressive miR-139-3p.

We recently determined the RNA sequencing-based microRNA (miRNA) expression signature of colorectal cancer (CRC). Analysis of the signature showed that the expression of both strands of pre-miR-139 (miR-139-5p, the guide strand, and miR-139-3p, the passenger strand) was significantly reduced in CRC tissues. Transient transfection assays revealed that expression of miR-139-3p blocked cancer cell malignant transformation (e.g., cell proliferation, migration, and invasion). Notably, expression of miR-139-3p markedly blocked RAC-alpha serine/threonine-protein kinase (AKT) phosphorylation in CRC cells. A combination of in silico database and gene expression analyses of miR-139-3p-transfected cells revealed 29 putative targets regulated by miR-139-3p in CRC cells. RNA immunoprecipitation analysis using an Argonaute2 (AGO2) antibody revealed that KRT80 was efficiently incorporated into the RNA-induced silencing complex. Aberrant expression of Keratin 80 (KRT80) was detected in CRC clinical specimens by immunostaining. A knockdown assay using small interfering RNA (siRNA) targeting KRT80 showed that reducing KRT80 expression suppressed the malignant transformation (cancer cell migration and invasion) of CRC cells. Importantly, inhibiting KRT80 expression reduced AKT phosphorylation in CRC cells. Moreover, hexokinase-2 (HK2) expression was reduced in cells transfected with the KRT80 siRNAs or miR-139-3p. The involvement of miRNA passenger strands (e.g., miR-139-3p) in CRC cells is a new concept in miRNA studies. Our tumor-suppressive miRNA-based approach helps elucidate the molecular pathogenesis of CRC.

A new overlapped delta-shaped anastomosis technique using linear staplers with reinforced bioabsorbable material for intracorporeal anastomosis during laparoscopic colectomy.

AIM: Totally laparoscopic colectomy with intracorporeal anastomosis (IA) is associated with less surgical trauma and wound related complications compared to laparoscopy-assisted colectomy with extracorporeal anastomosis. Delta shaped anastomosis is a widely popular IA technique. In this study, we discuss a construction technique for an overlapped delta-shaped anastomosis using a linear stapler with a reinforced bioabsorbable material. METHODS: We excised the bowel at a point 10 cm from the tumour on either sides and laid them in an overlapped fashion. The entry hole was created at a point 3 cm proximal to the right stump and 7 cm distal to the left stump on the antimesenteric side. Then, a 60-mm linear stapler with reinforced bioabsorbable material was inserted inside each lumen and fired. Finally, the common entry hole was fixed with a suture in the middle, the bowel was elevated holding the bioabsorbable material, and closed using the linear stapler in a delta-shaped manner. RESULTS: The technique was applied in five patients with tumours in the ascending, transverse, and descending colon. The median surgery time, anastomosis construction time and postoperative stay was 329 min (range 285-682 min), 19 min (range 14-29 min), and 12 days (range 9-15 days), respectively. There were no perioperative complications and only one postoperative complication. CONCLUSION: The overlapped delta-shaped anastomosis technique using linear staplers with reinforced bioabsorbable material appears to be both safe and feasible.

Implications of PD-1, Tim-3, and TIGIT Expression for Cancer Immunity and Pancreatic Cancer Prognosis.

BACKGROUND/AIM: The development and application of cancer immunotherapy to pancreatic cancer has not progressed because its efficacy has not been proven in clinical trials. In this study, we aimed to explore potential targets of immune checkpoint inhibitor therapy for pancreatic cancer treatment. MATERIALS AND METHODS: We collected resected specimens from 40 patients with pancreatic cancer who underwent resection at our Institution without any preoperative treatment. We evaluated the expression of molecules in the programmed death receptor-1 (PD-1), T cell immunoglobulin mucin-3 (Tim-3)/Galectin-9, and CD155/T cell immunoreceptor with Ig and ITIM domains (TIGIT) pathways using immunohistochemical staining. The correlation between the expression pattern of these molecules and patient prognosis were assessed using Kaplan-Meier analysis. RESULTS: An increased number of CD8+ T cells in pancreatic cancer tissue was significantly associated with a better patient prognosis. Additionally, patients with a higher ratio of PD-1 expression to CD8+ T cells had a worse prognosis. We observed no correlation between the Tim-3/Galectin-9 and CD155/TIGIT pathways and patient prognosis. CONCLUSION: Modifications in the immune environment to increase T cell infiltration into tumors could result in the PD-1 pathway becoming a potential target to treat pancreatic cancer using immune checkpoint inhibition.

A comparison of the surgical invasiveness and short-term outcomes between thoracoscopic and pneumatic mediastinoscopic esophagectomy for esophageal cancer.

PURPOSE: Minimally invasive esophagectomy (MIE) has been widely accepted as a treatment for esophageal cancer. This retrospective study compared the short-term outcomes and surgical invasiveness between thoracoscopic esophagectomy (TE) and mediastinoscopic esophagectomy with pneumomediastinum (pneumatic mediastinoscopic esophagectomy [PME]). METHODS: A total of 72 patients who underwent TE or PME were included and assessed for their surgical findings, postoperative complications, and inflammatory responses on postoperative day (POD) 1, 3, 5, and 7. RESULTS: The PME group exhibited a significantly shorter operative time and fewer lymph nodes retrieved than the TE group. Furthermore, the PME group tended to have greater incidences of recurrent laryngeal nerve palsy and lower incidences of atelectasis than the TE group. The PME group had significantly lower white blood cell counts on POD 5, serum C-reactive protein (CRP) levels on POD 3 than the TE group. CONCLUSION: PME seems to be less invasive than TE and can be considered the preferred option for patients with lower-stage esophageal cancer expected to have severe pleural adhesion or who cannot tolerate TE.

A prognostic scoring system for conversion surgery after trastuzumab-based chemotherapy for human epidermal growth factor receptor 2-positive advanced gastric cancer.

PURPOSE: To investigate the clinical indications and prognostic significance of surgical interventions after chemotherapy using trastuzumab-containing regimens for patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (AGC). METHODS: A total of 146 patients with AGC who underwent chemotherapy were enrolled in this retrospective study. Tumors with an immunohistochemistry (IHC) score of 3 + or an IHC score of 2 + plus fluorescence in situ hybridization positivity were defined as HER2-positive AGC. We devised a scoring system for predicting prognosis associated with conversion surgery. RESULTS: Thirty-three patients received trastuzumab-based chemotherapy for HER2-positive tumors. Multivariate analyses identified advanced age, peritoneal dissemination, histologically undifferentiated tumors, and tumor response of progressive disease as independent prognostic factors for a worse prognosis. Twelve patients with HER2-positive AGC underwent conversion surgery. The conversion surgery group of patients with HER2-positive AGC had a better prognosis than the chemotherapy-alone group. A prognostic scoring system based on age, peritoneal dissemination, and histological type was significantly correlated with the presence or absence of conversion surgery and the prognosis of patients with HER2-positive AGC. CONCLUSIONS: Our scoring system has the clinical potential to predict prognosis associated with conversion surgery after trastuzumab-containing chemotherapy for patients with HER2-positive AGC.

Changes in Chemotherapeutic Strategies and Their Prognostic Impact in Patients With Advanced Gastric Cancer.

BACKGROUND/AIM: To investigate changes in post-progression chemotherapy (PPC) before and after nivolumab approval and determine their prognostic impact. PATIENTS AND METHODS: A total of 146 patients with unresectable gastric cancer who had at least progressive disease after first- and/or second-line chemotherapy were retrospectively enrolled. RESULTS: Among the 146 patients, 46 and 23 received ramucirumab and nivolumab, respectively. Moreover, 95 and 62 patients received PPC after first- and second-line chemotherapy, respectively. Group B (i.e., at least chemotherapy after nivolumab approval) had significantly higher proportions of patients receiving ramucirumab therapy, nivolumab therapy, and PPC after first- or second-line chemotherapy compared to group A (i.e., termination of chemotherapy before nivolumab approval). Group A had significantly poorer prognosis than group B. Multivariate analysis showed that age, number of distant metastatic sites, and ramucirumab therapy were independent prognostic factors. CONCLUSION: Changes in chemotherapeutic strategies, including PPC, might contribute to improved prognosis in patients with advanced gastric cancer.

Multidisciplinary treatment of advanced or recurrent solid pseudopapillary neoplasm of the pancreas: three case reports.

BACKGROUND: Solid pseudopapillary neoplasm (SPN) is a rare pancreatic tumor that predominantly affects young females. Prognosis is excellent; however, 10-15% of patients show metastasis at the time of surgery or develop tumor recurrence after pancreatectomy. CASE PRESENTATION: We reviewed the clinical course of three patients with advanced or recurrent SPN and subsequently underwent multidisciplinary treatment at our institution between 2002 and 2019. The primary tumor was resected in all three patients, and metastases were also resected if indicated. Intensive combined therapy, including re-resection, chemotherapy, ablation, arterial chemoembolization, and radiation therapy, allowed all patients to survive for a long time. The literature review showed that resection seems to be more effective than other treatments for metastatic SPN. CONCLUSIONS: Multidisciplinary treatment, including resection, may improve the prognosis of patients with SPN with recurrence or metastasis.

Successful thoracoscopic resection of an esophageal bronchogenic cyst.

Esophageal bronchogenic cysts are rare, and since a limited number of cases has been reported, the treatment plan for asymptomatic patients is difficult. A 55-year-old man without any symptoms visited our hospital for further examination of an esophageal mass detected on simple computed tomography. Upper endoscopy showed the protruding, submucosal mass covered by normal mucosa, and endoscopic sonography confirmed hypoechoic lesions originating from the muscularis propria. The patient was diagnosed as having an esophageal duplication cyst and underwent thoracoscopic resection. Pathological findings were consistent with an esophageal bronchogenic cyst. The patient was discharged without any problems on the 6th postoperative day. Upper endoscopy was performed 6 months after surgery, and no evidence of esophageal diverticula or narrowing was present. In conclusion, early thoracoscopic resection of esophageal bronchogenic cysts, before appearance of the symptom, can be a considerable treatment option because it is less invasive and may be advantageous for obtaining a definitive diagnosis in patients who are candidates for safe surgical resection.

Postoperative recurrence with right cervical lymph node metastasis in hepatocellular carcinoma: a case report.

BACKGROUND: Hepatocellular carcinoma (HCC) patients with metastases to the cervical lymph nodes are extremely rare, and its clinical course is characterized by rapidly progressive disease. Hence, there have been no reports of metastatic cervical lymph node recurrence indicated after a long postoperative surveillance period. CASE PRESENTATION: The patient was a 63-year-old male who underwent right hepatectomy for HCC of the right upper lobe. Three years after resection, metastatic lymph node recurrence was detected in the subdiaphragm, superior mediastinum, and right cervical lymph nodes. The patient underwent excisional biopsy of the cervical lymph node, followed by molecular-targeted therapy and radiation therapy. Lenvatinib reduced the size of all metastatic lymph nodes and the patient survived for a relatively long period of 43 months after the recurrence was detected. CONCLUSIONS: After resection of HCC in the right upper lobe, there is the possibility of metastatic lymph node recurrence in unusual sites, including the cervical region, and lenvatinib may be effective in those recurrences.

RNA-Sequencing Based microRNA Expression Signature of Colorectal Cancer: The Impact of Oncogenic Targets Regulated by miR-490-3p.

To elucidate novel aspects of the molecular pathogenesis of colorectal cancer (CRC), we have created a new microRNA (miRNA) expression signature based on RNA-sequencing. Analysis of the signature showed that 84 miRNAs were upregulated, and 70 were downregulated in CRC tissues. Interestingly, our signature indicated that both guide and passenger strands of some miRNAs were significantly dysregulated in CRC tissues. These findings support our earlier data demonstrating the involvement of miRNA passenger strands in cancer pathogenesis. Our study focused on downregulated miR-490-3p and investigated its tumor-suppressive function in CRC cells. We successfully identified a total of 38 putative oncogenic targets regulated by miR-490-3p in CRC cells. Among these targets, the expression of three genes (IRAK1: p = 0.0427, FUT1: p = 0.0468, and GPRIN2: p = 0.0080) significantly predicted 5-year overall survival of CRC patients. Moreover, we analyzed the direct regulation of IRAK1 by miR-490-3p, and its resultant oncogenic function in CRC cells. Thus, we have clarified a part of the molecular pathway of CRC based on the action of tumor-suppressive miR-490-3p. This new miRNA expression signature of CRC will be a useful tool for elucidating new molecular pathogenesis in this disease.

Colorectal Cancer Patients Have Four Specific Bacterial Species in Oral and Gut Microbiota in Common-A Metagenomic Comparison with Healthy Subjects.

Oral microbiota is reportedly associated with gut microbiota and influences colorectal cancer (CRC) progression; however, the details remain unclear. This study aimed to evaluate the role of oral microbiota in CRC progression. Fifty-two patients with CRC and 51 healthy controls were included. Saliva and stool samples were collected, and microbiota were evaluated using 16S rRNA analysis and next-generation sequencing. Comparative analysis was performed on both groups. Linear discriminant analysis effect size (LEfSe) revealed the presence of indigenous oral bacteria, such as Peptostreptococcus, Streptococcus, and Solobacterium spp., at a significantly higher relative abundance in saliva and stool samples of CRC patients compared with controls. Next, CRC patients were divided into early stage (Stage I, II; n = 26; 50%) and advanced stage (Stage III, IV; n = 26; 50%) disease. LEfSe revealed that S. moorei was present at a significantly higher relative abundance in the advanced-stage group compared with the early-stage group, again consistent for both saliva and stool samples. Among bacterial species with significantly higher relative abundance in CRC patients, P. stomatis, S. anginosus, S. koreensis, and S. moorei originated from the oral cavity, suggesting indigenous oral bacteria may have promoted initiation of CRC carcinogenesis. Furthermore, S. moorei may influence CRC progression.

Prognostic Significance of HER2 Expression for Gastric Cancer With Clinically Para-aortic Lymph Node Metastasis.

BACKGROUND/AIM: To determine the prognostic utility of trastuzumab-based chemotherapy based on human epidermal growth factor receptor 2 (HER2) expression in patients with para-aortic lymph node (PAN) metastasis from gastric cancer. PATIENTS AND METHODS: A total of 41 patients with clinical PAN metastasis from gastric cancer who underwent chemotherapy were retrospectively enrolled. RESULTS: Eighteen (43.9%) patients had HER2-positive tumors and consequently, received trastuzumab-based chemotherapy. A total of 11 patients underwent surgery. HER2 status was significantly correlated with the number of distant metastatic sites, the presence or absence of trastuzumab-based chemotherapy, and the presence or absence of gastrectomy. HER2-positive patients had significantly better prognosis than HER2-negative patients. Multivariate analysis identified age and trastuzumab-based chemotherapy based on HER2 status as an independent prognostic factor. CONCLUSION: Assessing HER2 expression and subsequent trastuzumab-based chemotherapy can be an effective method for determining the prognosis of patients with PAN metastasis from gastric cancer.

Prognostic impact of surgery after chemotherapy for type 4 gastric cancer.

PURPOSE: To assess the clinical indications for, and prognostic impact of surgery after, chemotherapy for type 4 gastric cancer. METHODS: The subjects of this retrospective study were 67 patients who received chemotherapy for type 4 gastric cancer. The patients were grouped into those with progressive disease (PD group) and those without PD (non-PD group), according to the tumor response to chemotherapy. RESULTS: Distant metastases developed in 58 patients. With regard to tumor response, there were 16 patients in the PD group and 51 patients in the non-PD group. The prognosis of the PD group patients was significantly poorer than that of the non-PD group patients (p < 0.0001). R0 resection was performed for 21 of 23 patients who underwent surgery after chemotherapy. Multivariate analysis revealed tumor response and surgery as independent prognostic factors (p = 0.0001 and p = 0.0009, respectively). Moreover, multivariate analysis of the surgery group revealed that metastatic nodal status (N0-1 vs. N2-3) and residual tumor status (R0 vs. R1-2) were significant independent prognostic factors (p = 0.0258 and p = 0.0458, respectively). CONCLUSION: The findings of this study suggest that surgery after chemotherapy for type 4 gastric cancer may improve the prognosis of responders with N0-1 status, who undergo curative R0 resection.

Cellular-resolution gene expression profiling in the neonatal marmoset brain reveals dynamic species- and region-specific differences.

Precise spatiotemporal control of gene expression in the developing brain is critical for neural circuit formation, and comprehensive expression mapping in the developing primate brain is crucial to understand brain function in health and disease. Here, we developed an unbiased, automated, large-scale, cellular-resolution in situ hybridization (ISH)-based gene expression profiling system (GePS) and companion analysis to reveal gene expression patterns in the neonatal New World marmoset cortex, thalamus, and striatum that are distinct from those in mice. Gene-ontology analysis of marmoset-specific genes revealed associations with catalytic activity in the visual cortex and neuropsychiatric disorders in the thalamus. Cortically expressed genes with clear area boundaries were used in a three-dimensional cortical surface mapping algorithm to delineate higher-order cortical areas not evident in two-dimensional ISH data. GePS provides a powerful platform to elucidate the molecular mechanisms underlying primate neurobiology and developmental psychiatric and neurological disorders.

Anatomical study of the inferior mesenteric vein using three-dimensional computed tomography angiography in laparoscopy-assisted surgery for left-sided colorectal cancer.

PURPOSE: To investigate the drainage patterns of the inferior mesenteric vein (IMV) and measure the distance from the root of the inferior mesenteric artery (IMA) to the IMV using preoperative three-dimensional computed tomography (3D-CT) angiography in patients undergoing surgery for left-sided colorectal cancer. METHODS: In this retrospective study, we analyzed data collected prospectively on 167 consecutive patients who underwent laparoscopic left-sided colorectal cancer surgery between July, 2014 and August, 2019. The drainage pattern of the IMV and the distance from the root of the IMA to the IMV were evaluated using 3D-CT angiography. We also assessed intraoperative adverse events and postoperative outcomes. RESULTS: The IMV drained into the superior mesenteric vein (SMV) in 44 patients, into the confluence point of the SMV and splenic vein (SV) in 38 patients, into the SV in 83 patients, and into the middle colic vein in the remaining three patients. The median length from the root of the IMA to the IMV was 22.1 mm (1.3-84.9). IMV injury occurred in only one patient during surgery, but resulted in colonic ischemia. CONCLUSION: 3D-CT angiography is useful for the preoperative assessment of vascular anatomical variations of the IMV and IMA for safe intraoperative navigation and prevention of complications during laparoscopy-assisted left-sided colorectal surgery.