The usefulness of the endoscopic surgical skill qualification system in laparoscopic right hemicolectomy: a single-center, retrospective analysis with propensity score matching.

PURPOSE: Recently, a new certification system called the Endoscopic Surgical Skill Qualification System (ESSQS) has been launched in Japan to improve surgical safety. This study aimed to determine whether ESSQS-qualified surgeons affect the short- and long-term outcomes of laparoscopic right hemicolectomy. METHODS: A total of 187 colon cancer patients who underwent laparoscopic right hemicolectomy at Kindai University Hospital between January 2016 and December 2020 were enrolled. These patients were divided into two groups based on surgeries performed by ESSQS-qualified surgeons (QS group) and non-ESSQS-qualified surgeons (NQS group). The short- and long-term outcomes were compared between the two groups before and after propensity score matching (PSM). RESULTS: After PSM, 43 patients from each group were included in the matched cohort. In the short-term outcomes, the total operative time was significantly longer in the NQS group than in the QS group (229 vs. 174 min, p < 0.0001). However, there were no significant differences in the two groups regarding blood loss (0 vs. 0 ml, p = 0.7126), conversion (0.0% vs. 7.0%, p = 0.0779), Clavien-Dindo ≥ 2 complications (9.3% vs. 7.0%, p = 0.6933), mortality (2.3% vs. 0.0%, p = 0.3145), and postoperative hospital stay (9 vs. 9 days, p = 0.5357). In the long-term outcomes, there were no significant differences between the two groups in the 3-year overall survival (86.6% vs. 83.0%, p = 0.8361) and recurrence-free survival (61.7% vs. 72.0%, p = 0.3394). CONCLUSION: Laparoscopic right hemicolectomy performed by ESSQS-qualified surgeons contributed to shorter operative time. Under the supervision of ESSQS-qualified surgeons, almost equivalent safety and oncological outcomes are expected even in surgeries performed by non-ESSQS-qualified surgeons.

Lymphatic flow mapping during colon cancer surgery using indocyanine green fluorescence imaging.

With the development of surgical technology, indocyanine green (ICG) fluorescence navigation systems may be useful in various areas of colorectal surgery, including tumor location confirmation, bowel perfusion, ureter identification, and lymph node mapping. This review provides an overview of the current status of ICG-based navigation surgery in colorectal surgery, emphasizing its role in lymphatic flow mapping. This state-of-the-art approach will allow for appropriate oncological surgeries in the field of colorectal cancer and improve the patient's prognosis.

Laparoscopic complete mesocolic excision with central vascular ligation for splenic flexure colon cancer: short- and long-term outcomes.

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.

Performance of Idylla™ RAS-BRAF mutation test for formalin-fixed paraffin-embedded tissues of colorectal cancer.

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.

The technique for less infectious and earlier healing of stoma closure wound: negative pressure wound therapy with instillation and dwelling followed by primary closure.

BACKGROUND: Temporary stomas have been widely used to avoid the risk of complications such as anastomotic leakage after colorectal resection. Stoma closure is relatively easy; however, postoperative surgical site infection (SSI) may be a problem. Various methods have been used to reduce the incidence of SSI. We aimed to evaluate a new technique for stoma wound closure. METHODS: We enrolled patients who underwent stoma closure at our hospital between September 2019 and May 2020. We selected patients who lived far from our hospital and had difficulty visiting the hospital regularly and who agreed to undergo this surgical technique. We used negative pressure wound therapy with instillation and dwelling (NPWTi-d) and delayed primary closure for these patients. RESULTS: Four patients underwent NPWTi-d and delayed primary closure without the occurrence of SSI. The median postoperative hospital stay was 9 days (range: 7-14 days), and the median number of days to confirmation of epithelialization was 11.5 days (range: 10-16 days). CONCLUSION: The combined use of NPWTi-d and delayed primary closure for the stoma wound was very effective. This method may be a valuable new technique for wound management after stoma closure.

Cytotoxic T lymphocyte response to peptide vaccination predicts survival in stage III colorectal cancer.

We previously reported a phase I clinical trial of a peptide vaccine ring finger protein 43 (RNF43) and 34-kDa translocase of the outer mitochondrial membrane (TOMM34) combined with uracil-tegafur (UFT)/LV for patients with metastatic colorectal cancer (CRC), and demonstrated the safety and immunological responsiveness of this combination therapy. In this study, we evaluated vaccination-induced immune responses to clarify the survival benefit of the combination therapy as adjuvant treatment. We enrolled 44 patients initially in an HLA-masked fashion. After the disclosure of HLA, 28 patients were in the HLA-A*2402-matched and 16 were in the unmatched group. In the HLA-matched group, 14 patients had positive CTL responses specific for the RNF43 and/or TOMM34 peptides after 2 cycles of treatment and 9 had negative responses; in the HLA-unmatched group, 10 CTL responses were positive and 2 negative. In the HLA-matched group, 3-year relapse-free survival (RFS) was significantly better in the positive CTL subgroup than in the negative-response subgroup. Patients with negative vaccination-induced CTL responses showed a significant trend towards shorter RFS than those with positive responses. Moreover, in the HLA-unmatched group, the positive CTL response subgroup showed an equally good 3-year RFS as in the HLA-matched group. In conclusion, vaccination-induced CTL response to peptide vaccination could predict survival in the adjuvant setting for stage III CRC.

[A Case of Cecal Cancer Associated with Dermatomyositis].

We report a relatively rare case of cecal cancer with dermatomyositis. An 81-year-old man was diagnosed with dermatomyositis associated with the symptoms of eruption, limb muscle weakness, and difficulty swallowing. Colonoscopy revealed a type 2 tumor in the cecum. The patient underwent laparoscopic ileocecal resection. Although it was impossible for the patient to stand before the surgery, he could stand 10 days after the surgery and walk without assistance 14 days after the surgery. In addition, the eruption disappeared, and the preoperatively high creatine kinase(CK)value normalized. Dermatomyositis with malignant tumor has been reported to be associated with poor prognosis. Symptoms related to dermatomyositis may be improved by the resection of the associated tumor. Therefore, it is important to treat the malignant tumor when the patient's condition permits.

A Multicenter Phase 2 Study on the Feasibility and Efficacy of Neoadjuvant Chemotherapy Without Radiotherapy for Locally Advanced Rectal Cancer.

BACKGROUND: This prospective multicenter phase 2 study aimed to evaluate the feasibility and efficacy of neoadjuvant chemotherapy (NAC) without radiotherapy for locally advanced rectal cancer (LARC). METHODS: Patients with LARC (cStage II and III) were included in the study. Those with cT4b tumor were excluded. Six cycles of modified FOLFOX6 (mFOLFOX6) plus either bevacizumab or cetuximab, depending on KRAS status, were administered before surgery. The primary end point of the study was the R0 resection rate. The secondary end points were adverse effect, rate of NAC completion, postoperative complications, and pathologic complete response (pCR) rate. RESULTS: The study enrolled 60 patients from eight institutions. For the study, mFOLFOX6 was administered with cetuximab to 40 patients who had wild-type KRAS and with bevacizumab to 20 patients who had KRAS mutations. The completion rate for NAC was 88.4%. Sphincter-preserving surgery was performed for 43 patients and abdominoperineal resection for 17 patients. The median operation time was 335 min, and the median blood loss was 40 g. The R0 resection rate was 98.3%, and the pCR rate was 16.7%. The overall postoperative complication rate (≥grade 2) was 21.7%. The complications included anastomotic leakage (11.6%), surgical-site infection (6.7%), and urinary dysfunction (3.3%). The patients with wild-type KRAS did not differ significantly from those with KRAS mutations in terms of response rate, postoperative complication rate, and pCR rate. CONCLUSION: The findings show that NAC is a feasible and promising treatment option for LARC (This study is registered with UMIN-CTR, UMIN000005654).

The use of transureteroureterostomy during ureteral reconstruction for advanced primary or recurrent pelvic malignancy in the era of multimodal therapy.

PURPOSE: Cancerous involvement of a ureter is sometimes encountered in pelvic surgery for malignancy. We usually perform transureteroureterostomy (TUU) in cases of unilateral lower ureteral cancerous involvement. We report the outcomes in patients treated with TUU in our institute. METHODS: We retrospectively reviewed the medical records of 11 patients who underwent TUU between June 2006 and September 2015. RESULTS: The primary disease was colon cancer in five patients, rectal cancer in four, and uterine cervical cancer and ovarian cancer in one patient each. Early postoperative complications relevant to TUU occurred in four patients; however, three patients were managed conservatively and recovered quickly. Only one patient developed ureteral obstruction, which resulted from anastomotic hematoma. Follow-up periods ranged from 5 to 78 months with a median of 28 months. The median estimated glomerular filtration rate before and after TUU was 59 ml/min (range, 31-90 ml/min) and 62.0 ml/min (range, 43-127 mL/min), respectively. No patients experienced worsening of their renal function or recurrent urinary tract infection. CONCLUSIONS: Short-term outcomes are good and long-term renal function is maintained following TUU. TUU is considered a feasible technique for ureteral reconstruction for pelvic malignancy, and TUU has great potential in the era of multimodal therapy.

New laparoscopic procedure for left-sided pancreatic cancer-artery-first approach laparoscopic RAMPS using 3D technique.

BACKGROUND: For left-sided pancreatic ductal adenocarcinoma (PDAC), radical antegrade modular pancreatosplenectomy (RAMPS) is a reasonable surgical approach for tumor-free margin resection and systemic lymph node clearance. In pancreaticoduodenectomy for PDAC, the superior mesenteric artery (SMA)-first approach (or the "artery-first approach") has become the standard procedure. With improvements in laparoscopic instruments and techniques, some surgeons attempted to apply laparoscopic RAMPS (L-RAMPS) for carefully selected patients with left-sided PDAC. However, owing to several technical difficulties in this procedure, its application remains uncommon. Moreover, the artery-first approach in L-RAMPS has not been reported. Here, we developed the artery-first approach L-RAMPS for left-sided PDAC and have presented the same in this report. CASE PRESENTATION: Between June 2014 and July 2015, 16 patients with left-sided PDAC were referred to our division for pancreatic resection. The following technique was used for performing L-RAMPS on 3 of the 16 patients (19%). Six trocars were placed. After opening the omental bursa, only the middle segment of the pancreas was initially separated from both the left renal vein and the SMA. We termed this procedure as the "artery-first approach using a dome-shaped dorsomedial dissection (3D) technique." This 3D technique enabled the interruption of the entire arterial supply to the specimen while preserving the venous drainage through the splenic vein for preventing venous congestion. The technique also contributed to the early detection of no tumor infiltration into the SMA and the early determination of posterior dissection plane. After pancreatic neck transection, the splenic artery and vein were divided. Finally, the pancreatic tail and spleen were dissected in a right-to-left direction. All operations were completed without any intraoperative complications. The median blood loss and retrieved lymph node count were 75 mL and 37, respectively, which were superior to those reported by other previous studies on L-RAMPS. All resection margins were free of carcinoma. No severe postoperative complications were observed. CONCLUSIONS: The artery-first approach L-RAMPS using 3D technique is safe and feasible to perform. The significance of our proposed procedure is minimal blood loss and precise lymphadenectomy. Therefore, this novel technique may become the preferred treatment for left-sided PDAC in selected cases.

Liver necrosis shortly after pancreaticoduodenectomy with resection of the replaced left hepatic artery.

BACKGROUND: Surgeons, in general, underestimate the replaced left hepatic artery (rLHA) that arises from the left gastric artery (LGA), compared with the replaced right hepatic artery (rRHA), especially in standard gastric cancer surgery. During pancreaticoduodenectomy (PD), preservation of the rRHA arising from the superior mesenteric artery (SMA) is widely accepted to prevent critical postoperative complications, such as liver necrosis, bile duct ischemia, and biliary anastomotic leakage. In contrast, details of complication onset following rLHA resection remain unknown. We report two cases of postoperative liver necrosis shortly after rLHA resection during PD for advanced gastric cancer. CASE PRESENTATION: Both cases had advanced gastric cancer with infiltration of the pancreatic head. In case 1, the rLHA comprised segment 2/3 artery (A2 + A3), which arose from the LGA. The rRHA originated from the SMA, and the segment 4 artery (A4) was a branch of the rRHA. We conducted PD with combined en bloc resection of both the rLHA and rRHA, and anastomosis between the distal and proximal stumps of the rRHA and LGA, respectively. The divided A2 + A3 was not reconstructed. In case 2, the rLHA comprised segment 2 artery (A2) only, which arose from the LGA. The segment 3/4 artery and the RHAs originated from the proper hepatic artery. We undertook PD with combined en bloc resection of A2 without vascular reconstruction. In both patients, serious necrosis of the lateral segment of the liver occurred within 6 days after PD. Case 1 recovered with conservative management, whereas case 2 required lateral segmentectomy of the liver. Pathologically, the necrotic area in case 2 was apparently circumscribed and confined to segment 2 of the liver, potentially implicating rLHA resection during PD as causing hepatic necrosis. CONCLUSIONS: During PD, rLHA resection can cause serious liver necrosis. Therefore, this artery should be preserved as far as oncologically acceptable. In cases that require rLHA resection during PD due to tumor conditions, surgeons should carefully monitor postoperative course while keeping in mind the possible necessity of urgent hepatectomy.

[Survival Benefit by Combined Administration of Cyclophosphamide, Lentinula edodes Mycelia Extract(LEM), and Ganoderma lucidum Mycelia Extract(MAK)in S1018B10 Tumor-Bearing Mice].

Cyclophosphamide(CY)was intraperitoneally administered once a week to C57BL/10mice that had received Rous sarcoma virus(RSV)-induced S1018B10 syngeneic tumor transplantation and in whom tumor diameter exceeded 4.5 mm. Survival was prolonged in a group of mice that also received a mixture of LEM and MAK orally. When splenic cells were cultured under mitomycin C-treated S1018B10 stimulation and the S1018B10-directed cell killing ability was examined, the effector cells were found to be F4/80 - DC/Mф cells. Flow cytometric analysis showed that the proportion of F4/80- DC/Mф cells in the splenic cell culture of the CY+LEM+MAK treatment group was higher than that in the untreated group. The ratio of F4/80+ CD8a+ cells in the CY+LEM+MAK treatment group was lower than that in the untreated group.

[A Case of Local Resection for Rectal GIST Following Neoadjuvant Imatinib Mesylate Treatment].

A 67-year-old woman presented with bloody stools and constipation. A rectal digital examination revealed a smooth and elastic hard tumor in the posterior wall of the rectum. We diagnosed the tumor as rectal GIST measuring 5 cm in diameter. Because the patient desired anal preservation, neoadjuvant imatinib mesylate(IM)(400mg/day)treatment was administered. Although the diameter of the tumor reduced to 2 cm in the third week of administration, the patient experienced erythema-type drug eruption(Grade 3). We discontinued the IM treatment and initiated steroid therapy. After the eruption had disappeared, IM treatment was resumed, initially with half doses. Local transanal resection was performed 36days after the neoadjuvant IM treatment. Currently, the indication and the administration period of IM for preoperative treatment is not clear. It may be necessary to accumulate cases to evaluate neoadjuvant IM therapy.

A retrospective analysis on the utility and complications of upper arm ports in 433 cases at a single institute.

BACKGROUND: We have employed upper arm central venous ports (UACVPs) since 2006 for long-term intravenous chemotherapy (CTx) or fluid supplementation. We evaluated the long-term availability of CVPs implanted in the upper arm to determine whether UACVPs could be one of the treatment options besides chest CVPs in terms of CVP-related complications. METHODS: We reviewed the medical records of all patients who underwent subcutaneous implantation of UACVPs at Kyoto University Hospital from 1 April, 2006 to 30 June, 2009. We assessed the indwelling duration of the UACVPs and the incidences of early and late UACVP-related complications. RESULTS: A total of 433 patients underwent subcutaneous implantation of UACVPs during this time period. The cumulative follow-up period was 251,538 catheter days, and the median duration of UACVP indwelling was 439.0 days (1-2, 24). There was no UACVP-related mortality throughout the study period. A total of 83 UACVP-related complications occurred (19.2 %), including 43 cases of infection (9.9 %, 0.17/1000 catheter days), ten cases of catheter-related thrombosis (2.3 %, 0.040/1000 catheter days), ten cases of occlusion (2.3 %, 0.040/1000 catheter days), nine cases of catheter dislocation (2.0 %, 0.036/1000 catheter days), five cases of port leakage (1.2 %, 0.019/1000 catheter days), four cases of skin dehiscence (0.9 %, 0.015/1000 catheter days) and two cases of port chamber twist (0.5 %, 0.008/1000 catheter days). The removal-free one-year port availability was estimated at 87.8 %. CONCLUSIONS: UACVPs were of long-term utility, with complication rates comparable to those of chest CVPs previously reported.

Clinical efficacy of liver resection after downsizing systemic chemotherapy for initially unresectable liver metastases.

BACKGROUND: This study sought to clarify the clinical benefits of liver resection after downsizing systemic chemotherapy for initially unresectable colorectal liver metastases (CLM). METHODS: Survival and clinical characteristics of CLM patients who underwent resection between January 2001 and December 2013 were retrospectively assessed. The study cohort of 88 patients with limited liver disease who underwent curative liver resection comprised 34 with initially resectable synchronous disease (synchronous group), 38 with initially resectable metachronous disease (metachronous group), and 16 with initially unresectable converted disease (conversion group). RESULTS: The median duration of follow-up for the overall study population was 33 (1-98) months. Overall survival (OS) in the conversion group was not significantly different from that in the other groups. However, disease-free survival (DFS) in the conversion group was significantly shorter than that in the synchronous group. The median DFS was 19.1 months in the synchronous group, 16.6 months in the metachronous group, and 15.3 months in the conversion group. Most patients in the conversion group had recurrence shortly after liver resection in the remnant liver with or without metastases at other sites, but many could undergo repeat hepatectomy or resection of the metastases at other sites. CONCLUSIONS: Although the converted patients tended to have recurrence shortly after liver resection, survival could be prolonged by repeat hepatectomy or resection of metastases at other sites. Liver resection after downsizing chemotherapy appears to be efficacious for patients with initially unresectable CLM and may result in long-term outcomes equivalent to those of patients with initially resectable CLM.

Intramural metastasis of T1 rectal cancer: report of a case report.

BACKGROUND: Intramural metastasis (IM) is extremely rare in colorectal cancer, although it often occurred in esophageal cancer. CASE PRESENTATION: We report a rare case of T1 rectal cancer with IM which was successfully resected by laparoscopic surgery. A 62-year-old man was admitted to our institution for the treatment of rectal cancer detected by medical examination. Colonoscopy revealed two tumors in the rectum: a type II rectal cancer of 2 cm in diameter located 5 cm proximal to the anal verge and a submucosal tumor of 1 cm in diameter located approximately 1.5 cm proximal to the rectal cancer. Abdominal computed tomography (CT), magnetic resonance imaging (MRI), and transrectal ultrasonography indicated the rectal cancer invaded into the submucosal layer with no metastasis to regional lymph nodes or distant organs. The patient underwent laparoscopic intersphincteric resection.Histopathological analysis revealed that the rectal cancer was moderately differentiated adenocarcinoma (stage I; pT1N0M0 according to the 7th edition of UICC) with severe lymphovascular invasion (ly1, v3) and that the submucosal tumor was composed of moderately differentiated adenocarcinoma proliferating within the muscularis propria. A number of features of the submucosal tumor indicated that this was an IM of the rectal cancer: clearly distinct location from the rectal cancer, growth predominantly within the muscularis propria, similar structural and cellular heterogeneity, and the presence of tumor emboli within vascular vessels. The patient was postoperatively followed for more than 4 years without any sign of recurrence. CONCLUSIONS: To the best of our knowledge, this is the first report of the T1 rectal cancer with IM.

Laparoscopic Total Gastrectomy for Remnant Gastric Cancer Following Distal Gastrectomy with Radical Lymphadenectomy.

BACKGROUND/AIMS: In cases of remnantgastric cancer (RGC) with previous lymphadenectomy, laparoscopic total gastrectomy (LTG) is still uncommon because of the technical difficulties associated with adhesions from previous gastric cancer surgery and variations in anastomotic reconstruction. Here we demonstrate our procedure of LTG for RGC following distal gastrectomy (DG) with radical lymphadenectomy and review its clinical results. METHODOLOGY: From October 2008 to June 2014, we carried out three consecutive LTGs for RGC with previous lymphadenectomy. All cases had a past history of primary gastric cancer that had required open or laparoscopic DG with D2 radical lymphadenectomy. The preoperative TNM statuses of RGC were all cT1N0M0. RESULTS: All patients successfully underwent LTG without open conversion or intraoperative complications. The median operative duration was 360 min; the median blood loss was 45 mL. The median number of retrieved lymph nodes was 23. No complications occurred postoperatively, and the median length of postoperative hospitalization was 20 days. The pathological TNM statuses of the RGC were all T1N0M0. Resection margins were negative in all cases (R0). CONCLUSIONS: Our novel procedure of LTG for RGC following DG with radical lymphadenectomy is technically acceptable, safe, and feasible.

Risk factors for anastomotic leakage after laparoscopic low anterior resection with DST anastomosis.

BACKGROUND: Laparoscopic rectal surgery involving rectal transection and anastomosis with stapling devices is technically difficult. The aim of this study was to evaluate the risk factors for anastomotic leakage (AL) after laparoscopic low anterior resection (LAR) with double-stapling technique (DST) anastomosis. METHODS: This was a retrospective single-institution study of 154 rectal cancer patients who underwent laparoscopic LAR with DST anastomosis between June 2005 and August 2013. Patient-, tumor-, and surgery-related variables were examined by univariate and multivariate analyses. The outcome of interest was clinical AL. RESULTS: The overall AL rate was 12.3% (19/154). In univariate analysis, tumor size (P = 0.001), operative time (P = 0.049), intraoperative bleeding (P = 0.037), lateral lymph node dissection (P = 0.009), multiple firings of the linear stapler (P = 0.041), and precompression before stapler firings (P = 0.008) were significantly associated with AL. Multivariate analysis identified tumor size (odds ratio [OR] 4.01; 95% confidence interval [CI] 1.25-12.89; P = 0.02) and precompression before stapler firings (OR 4.58; CI 1.22-17.20; P = 0.024) as independent risk factors for AL. In particular, precompression before stapler firing tended to reduce the AL occurring in early postoperative period. CONCLUSIONS: Using appropriate techniques, laparoscopic LAR with DST anastomosis can be performed safely without increasing the risk of AL. Important risk factors for AL were tumor size and precompression before stapler firings.