Revolutionizing sphincter preservation in ultra-low rectal cancer: exploring the potential of transanal endoscopic intersphincteric resection (taE-ISR): a propensity score-matched cohort study.

BACKGROUND: With the optimization of neoadjuvant treatment regimens, the indications for intersphincteric resection (ISR) have expanded. However, limitations such as unclear surgical field, impaired anal function, and failure of anal preservation still exist. Transanal total mesorectal excision can complement the drawbacks of ISR. Therefore, this study combined these two techniques and proposed transanal endoscopic intersphincteric resection (taE-ISR), aiming to explore the value of this novel technique in anal preservation for ultra-low rectal cancer. MATERIAL AND METHODS: Four high-volume centres were involved. After 1:1 propensity score-matching, patients with ultra-low rectal cancer underwent taE-ISR ( n =90) or ISR ( n =90) were included. Baseline characteristics, perioperative outcomes, pathological results, and follow-up were compared between the two groups. A nomogram model was established to assess the potential risks of anal preservation. RESULTS: The incidence of adjacent organ injury (0.0% vs. 5.6%, P =0.059), positive distal resection margin (1.1% vs. 8.9%, P =0.034), and incomplete specimen (2.2% vs. 13.3%, P =0.012) were lower in taE-ISR group. Moreover, the anal preservation rate was significantly higher in taE-ISR group (97.8% vs. 82.2%, P =0.001). Patients in the taE-ISR group showed a better disease-free survival ( P =0.044) and lower cumulative recurrence ( P =0.022) compared to the ISR group. Surgery procedure, tumour distance, and adjacent organ injury were factors influencing anal preservation in patients with ultra-low rectal cancer. CONCLUSION: taE-ISR technique was safe, feasible, and improved surgical quality, anal preservation rate and survival outcomes in ultra-low rectal cancer patients. It held significant clinical value and showed promising application prospects for anal preservation.

Natural orifice specimen extraction surgery versus small-incision assisted laparoscopic radical right hemicolectomy.

Conventional laparoscopic-assisted right hemicolectomy requires a small abdominal incision to extract the specimen, which becomes an important source of postoperative complications and impairs perioperative experience. Transvaginal natural orifice specimen extraction surgery (NOSES VIIIA) avoids this small incision by extracting the specimen through the vagina. Here we describe the design of a multicenter, open-label, parallel, noninferior, phase III randomized controlled trial (NCT05495048). The aim of this study is to confirm that the NOSES VIIIA procedure is not inferior to small-incision assisted right hemicolectomy in long-term oncological efficacy. A total of 352 female patients with right colon adenocarcinoma/high-grade intraepithelial neoplasia will be randomly assigned to the NOSES VIIIA arm and the small-incision arm in a 1:1 ratio. The primary end point of this trial is 3 year disease-free survival. Clinical Trial Registration: NCT05495048 (ClinicalTrials.gov).

Predicting multiple linear stapler firings in double stapling technique with an MRI-based deep-learning model.

Multiple linear stapler firings is a risk factor for anastomotic leakage (AL) in laparoscopic low anterior resection (LAR) using double stapling technique (DST) anastomosis. In this study, our objective was to establish the risk factors for ≥ 3 linear stapler firings, and to create and validate a predictive model for ≥ 3 linear stapler firings in laparoscopic LAR using DST anastomosis. We retrospectively enrolled 328 mid-low rectal cancer patients undergoing laparoscopic LAR using DST anastomosis. With a split ratio of 4:1, patients were randomly divided into 2 sets: the training set (n = 260) and the testing set (n = 68). A clinical predictive model of ≥ 3 linear stapler firings was constructed by binary logistic regression. Based on three-dimensional convolutional networks, we built an image model using only magnetic resonance (MR) images segmented by Mask region-based convolutional neural network, and an integrated model based on both MR images and clinical variables. Area under the curve (AUC), sensitivity, specificity, accuracy, positive predictive value (PPV), and Youden index were calculated for each model. And the three models were validated by an independent cohort of 128 patients. There were 17.7% (58/328) patients received ≥ 3 linear stapler firings. Tumor size ≥ 5 cm (odds ratio (OR) = 2.54, 95% confidence interval (CI) = 1.15-5.60, p = 0.021) and preoperative carcinoma embryonic antigen (CEA) level > 5 ng/mL [OR = 2.20, 95% CI = 1.20-4.04, p = 0.011] were independent risk factors associated with ≥ 3 linear stapler firings. The integrated model (AUC = 0.88, accuracy = 94.1%) performed better on predicting ≥ 3 linear stapler firings than the clinical model (AUC = 0.72, accuracy = 86.7%) and the image model (AUC = 0.81, accuracy = 91.2%). Similarly, in the validation set, the integrated model (AUC = 0.84, accuracy = 93.8%) performed better than the clinical model (AUC = 0.65, accuracy = 65.6%) and the image model (AUC = 0.75, accuracy = 92.1%). Our deep-learning model based on pelvic MR can help predict the high-risk population with ≥ 3 linear stapler firings in laparoscopic LAR using DST anastomosis. This model might assist in determining preoperatively the anastomotic technique for mid-low rectal cancer patients.

Quantifying the air quality impact of ship emissions in China's Bohai Bay.

Bohai Bay, as a significant economic bay area in China, has experienced considerable ecological consequences during its rapid economic development. One of the major environmental challenges is the emission of air pollutants from ships, which has had a severe impact on regional air quality and the health of residents. To assess the influence of pollutants on the air quality around the Bohai Bay area, a Weather Research and Forecasting and Community Multiscale Air Quality (WRF-CMAQ) model was established using a 9 km × 9 km high-resolution ship emission gridded inventory from 2018. The WRF-CMAQ model was employed to compare two scenarios: vessel emissions and non-vessel emissions, in order to evaluate the impact of ship emissions. By analyzing the pollutant concentrations in Bohai Bay and the degree of change in pollutant concentration in six cities under these two scenarios, significant differences were observed. Furthermore, a comparison of the hourly concentration contributions of ship emissions between port cities and inland cities within the same region revealed that inland cities were less affected by ship emissions. The main contributing factors to this disparity were identified as wind direction and wind speed.

Pathological and perioperative outcomes of extracorporeal versus intracorporeal anastomosis in laparoscopic transverse colon cancer resection: retrospective multicentre study.

BACKGROUND: The aim of this study was to compare the pathological and perioperative outcomes of extracorporeal versus intracorporeal anastomosis after laparoscopic transverse colon cancer resection. METHODS: In this retrospective study, patients from seven institutions in China who underwent laparoscopic resection of transverse colon cancer between 2019 and 2021 were selected and included. Either extended right hemicolectomy or transverse colectomy/extended left hemicolectomy was performed. The clinical characteristics and the pathological and perioperative outcomes were compared between patients undergoing extracorporeal or intracorporeal anastomosis. Resection margin lengths were measured on formalin-fixed specimens and an inadequate margin was defined as less than 4.2 cm between the division and the tumour. The outcome of interest was the prevalence of specimens with an inadequate margin. Length of incision, bowel function recovery, hospital stay, early postoperative pain (first day after surgery), 30-day complications, and nodal harvest were investigated as secondary outcomes. RESULTS: Of 411 patients treated during the study interval, 370 patients with transverse colon cancer were included (23.2 per cent treated with intracorporeal anastomosis and 76.8 per cent treated with extracorporeal anastomosis). The prevalence of specimens with inadequate margins was lower in the intracorporeal anastomosis group compared with the extracorporeal anastomosis group in patients undergoing extended right hemicolectomy (P = 0.045) and in patients undergoing transverse colectomy/extended left hemicolectomy (P = 0.030). In multivariate analysis, extracorporeal anastomosis (OR 2.94 (95 per cent c.i. 1.33 to 6.49), P = 0.008) and transverse colectomy/extended left hemicolectomy (OR 1.75 (95 per cent c.i. 1.03 to 2.96), P = 0.038) were independent risk factors for specimens with an inadequate margin. Intracorporeal anastomosis was associated with a shorter incision length (P < 0.001), an earlier recovery of bowel function (P = 0.035), a shorter postoperative hospital stay (P = 0.042), less early postoperative pain (P < 0.001), a longer specimen length (P = 0.042), a longer resection margin (P = 0.007), and a greater lymph node harvest (P = 0.036). There was no statistically significant difference in 30-day complications. CONCLUSION: Patients with transverse colon cancer have better perioperative outcomes, fewer margins of less than 4.2 cm, and larger lymph node harvests when the anastomosis is performed intracorporeally. Further studies are needed to confirm these findings. REGISTRATION NUMBER: NCT05061199 (www.clinicaltrials.gov).

Structured training curricula for robotic colorectal surgery in China: does laparoscopic experience affect training effects?

Background: Robotic surgery has been widely adopted for colorectal cancer (CRC). Many surgeons in China have completed structured training programs and have performed robotic colorectal surgeries. This multicenter study aimed to evaluate the training effects of structured training curricula in China for surgeons with different laparoscopic experiences during their initial implementation of robotic colorectal surgery. Methods: Ten surgeons from five high-volume centers participated in this retrospective study. The baseline characteristics, perioperative data, and pathological outcomes were compared between the first 15 robotic surgeries performed by five surgeons with extensive laparoscopic experience (group A) and the first 15 robotic surgeries performed by five surgeons with limited laparoscopic experience (group B) at each center. Results: Compared with group B, group A showed shorter operation time (200.9 vs. 254.2 min, P<0.001), less blood loss (100.0 vs. 150.0 mL, P=0.025), and a lower incidence of intraoperative complications (2.7% vs. 21.4%, P=0.015). The reoperation rate (1.3% vs. 5.3%, P=0.036) and postoperative complication rate (6.7% vs. 22.7%, P=0.025) were significantly lower in group A than in group B. There were no statistically significant differences in baseline characteristics (e.g., age, sex, and tumor location) and pathological information (e.g., tumor stage, lymph node count, and tumor size) between the two groups. Radical resection (R0) was performed in all cases. Conclusions: In China, structured training curricula can help surgeons with extensive laparoscopic experience make a smooth transition from laparoscopic to robotic surgery. However, the higher intraoperative and postoperative complication rates indicate that structured training curricula still require further refinement for surgeons with limited laparoscopic experience.

Infrapyloric (No. 206) and greater curvature (No. 204) lymph node metastasis in adenocarcinoma located in the right half of the transverse colon (InCLART Study): protocol for a multicentre prospective observational study.

INTRODUCTION: In the case of right-sided transverse colon cancer (RTCC) and hepatic flexure colon cancer (HFCC), there is a potential connection of lymph drainage between mesentery and greater omentum. However, most previous reports have been limited case series with No. 206 and No. 204 lymph node (LN) dissection for RTCC and HFCC. METHODS AND ANALYSIS: The InCLART Study is a prospective observational study aiming to enrol 427 patients with RTCC and HFCC treated at 21 high-volume institutions in China. The prevalence of infrapyloric (No. 206) and greater curvature (No. 204) LN metastasis and short-term outcomes will be investigated in a consecutive series of patients with T2 or deeper invasion RTCC or HFCC, following the principle of complete mesocolic excision with central vascular ligation. Primary endpoints were performed to identify the prevalence of No. 206 and No. 204 LN metastasis. Secondary analyses will be used to estimate prognostic outcomes, intraoperative and postoperative complications, the consistency of preoperative evaluation and postoperative pathological results of LN metastasis. ETHICS AND DISSEMINATION: Ethical approval for the study has been granted by the Ruijin Hospital Ethics Committee (approval number: 2019-081) and has been or will be approved successively by each participating centre's Research Ethics Board. The findings will be disseminated in peer-reviewed publications. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03936530; https://clinicaltrials.gov/ct2/show/NCT03936530).

Magnetic resonance imaging-based deep learning model to predict multiple firings in double-stapled colorectal anastomosis.

BACKGROUND: Multiple linear stapler firings during double stapling technique (DST) after laparoscopic low anterior resection (LAR) are associated with an increased risk of anastomotic leakage (AL). However, it is difficult to predict preoperatively the need for multiple linear stapler cartridges during DST anastomosis. AIM: To develop a deep learning model to predict multiple firings during DST anastomosis based on pelvic magnetic resonance imaging (MRI). METHODS: We collected 9476 MR images from 328 mid-low rectal cancer patients undergoing LAR with DST anastomosis, which were randomly divided into a training set (n = 260) and testing set (n = 68). Binary logistic regression was adopted to create a clinical model using six factors. The sequence of fast spin-echo T2-weighted MRI of the entire pelvis was segmented and analyzed. Pure-image and clinical-image integrated deep learning models were constructed using the mask region-based convolutional neural network segmentation tool and three-dimensional convolutional networks. Sensitivity, specificity, accuracy, positive predictive value (PPV), and area under the receiver operating characteristic curve (AUC) was calculated for each model. RESULTS: The prevalence of ≥ 3 linear stapler cartridges was 17.7% (58/328). The prevalence of AL was statistically significantly higher in patients with ≥ 3 cartridges compared to those with ≤ 2 cartridges (25.0% vs 11.8%, P = 0.018). Preoperative carcinoembryonic antigen level > 5 ng/mL (OR = 2.11, 95%CI 1.08-4.12, P = 0.028) and tumor size ≥ 5 cm (OR = 3.57, 95%CI 1.61-7.89, P = 0.002) were recognized as independent risk factors for use of ≥ 3 linear stapler cartridges. Diagnostic performance was better with the integrated model (accuracy = 94.1%, PPV = 87.5%, and AUC = 0.88) compared with the clinical model (accuracy = 86.7%, PPV = 38.9%, and AUC = 0.72) and the image model (accuracy = 91.2%, PPV = 83.3%, and AUC = 0.81). CONCLUSION: MRI-based deep learning model can predict the use of ≥ 3 linear stapler cartridges during DST anastomosis in laparoscopic LAR surgery. This model might help determine the best anastomosis strategy by avoiding DST when there is a high probability of the need for ≥ 3 linear stapler cartridges.

Safety and feasibility of laparoscopic surgery for colorectal and gastric cancer under the Chinese multi-site practice policy: admittance standards of competence are needed.

Background: The multi-site practice (MSP) policy has been practiced in China over 10 years. This study aimed to investigate the safety and feasibility of performing laparoscopic surgery for colorectal cancer (LSCRC) and gastric cancer (LSGC) under the Chinese MSP policy. Methods: We collected and analysed the data from 1,081 patients who underwent LSCRC or LSGC performed by one gastrointestinal surgeon in his original hospital (n = 573) and his MSP institutions (n = 508) between January 2017 and December 2020. Baseline demographics, intraoperative outcomes, post-operative recovery, and pathological results were compared between the original hospital and MSP institutions, as well as between MSP institutions with and without specific competence (surgical skill, operative instrument, perioperative multi-discipline team). Results: In our study, 690 patients underwent LSCRC and 391 patients underwent LSGC. The prevalence of post-operative complications was comparable for LSCRC (11.5% vs 11.1%, P = 0.89) or LSGC (15.2% vs 12.6%, P = 0.46) between the original hospital and MSP institutions. However, patients in MSP institutions without qualified surgical assistant(s) and adequate instruments experienced longer operative time and greater intraoperative blood loss. The proportion of patients with inadequate lymph-node yield was significantly higher in MSP institutions than in the original hospital for both LSCRC (11.5% vs 21.2%, P < 0.01) and LSGC (9.8% vs 20.5%, P < 0.01). Conclusion: For an experienced gastrointestinal surgeon, performing LSCRC and LSGC outside his original hospital under the MSP policy is safe and feasible, but relies on the precondition that the MSP institutions are equipped with qualified surgical skills, adequate operative instruments, and complete perioperative management.

Light triggered release of a triple action porphyrin-cisplatin conjugate evokes stronger immunogenic cell death for chemotherapy, photodynamic therapy and cancer immunotherapy.

Photodynamic therapy (PDT) has emerged as an attractive therapeutic approach which can elicit immunogenic cell death (ICD). However, current ICD inducers are still very limited as the representative ICD induces of photosensitizers can only evoke insufficient ICD to achieve unsatisfactory cancer immunotherapy. Herein, we demonstrated the use of a triple action cationic porphyrin-cisplatin conjugate (Pt-1) for drug delivery by a reactive oxygen species (ROS) sensitive polymer as nanoparticles (NP@Pt-1) for combined chemotherapy, PDT and immunotherapy. This unique triple action Pt-1 contains both chemotherapeutic Pt drugs and Porphyrin as a photosensitizer to generate ROS for PDT. Moreover, the ROS generated by Pt-1 can on the one hand degrade polymer carriers to release Pt-1 for chemotherapy and PDT. On the other hand, the ROS generated by Pt-1 subsequently triggered the ICD cascade for immunotherapy. Taken together, we demonstrated that NP@Pt-1 were the most effective and worked in a triple way. This study could provide us with new insight into the development of nanomedicine for chemotherapy, PDT as well as cancer immunotherapy.

Structured training curriculums for transanal total mesorectal excision in China: refinement is needed.

Background: Transanal total mesorectal excision (TaTME) is an alternative for mid-low rectal cancer. In China, this procedure has been performed in high-volume centers with structured training curriculums. The efficacy of the TaTME structured training curriculums in China is still unclear. This multicenter study aimed to explore the effectiveness of the structured training curriculums in China. Methods: Seven high-volume centers in China participated in this study. The first 25 patients who underwent TaTME in each center were enrolled. In the cohort, patients were divided into 3 groups. The first 5 procedures (group 1) were performed under proctoring according to the requirement of structured training curriculums. The latter 20 cases without proctoring were split into 2 groups (10 cases in each group, groups 2 and 3) according to the order of operation date. The baseline characteristics, perioperative complications, and pathological outcomes were compared between groups 1 and 2, as well as between groups 2 and 3. Results: Symptomatic anastomotic leakage (AL) occurred in 18.6% of the patients in group 2 compared with 5.7% in group 1 (P1=0.08) and 5.0% in group 3 (P2=0.04). Seven (11.3%) patients in group 2 developed defecation disorders whereas no patients had this complication in group 3 (P2=0.02). Compared with group 2, the operative time was shorter (235 vs. 223 min, P2=0.40), while the rates of intraoperative complications (15.7% vs. 5.7%, P2=0.10), postoperative complications (31.3% vs. 25.7%, P2=0.06), AL (20.0% vs. 8.6%, P2=0.04), and positive distal resection margin (DRM) (7.5% vs. 2.9%, P2=0.27) were lower in group 3. Conclusions: The effect of the structured training curriculums was acceptable but needed further improvement. The prevalence of anastomosis-related complications and the quality control of specimens are still not optimal, and measures for refinement (for example, more cases under proctoring) are needed in the curriculums.

Risk factors of chylous ascites and its relationship with long-term prognosis in laparoscopic D3 lymphadenectomy for right colon cancer.

BACKGROUND: Chylous ascites (CA) after laparoscopic D3 lymphadenectomy for right colon cancer is not rare. However, the risk factors for CA have not been fully explored. Few studies have investigated the effect of CA on long-term prognosis. METHODS: The clinical data of patients with right colon cancer who underwent laparoscopic D3 lymphadenectomy in five centers from January 2013 to December 2018 were retrospectively collected. Univariate and multivariate analyses were performed to determine the clinicopathological factors associated with CA. Then, the long-term prognosis of patients with and without CA was compared by propensity score matching and Kaplan-Meier survival analysis. RESULTS: The incidence of CA was 4.4% (48/1090). Pathological T stage (p = 0.025), dissection along the left side of the superior mesenteric artery (p < 0.001) and the number of retrieved lymph nodes (p < 0.001) were independent risk factors for CA. After propensity score matching, 48 patients in the CA group and 353 patients in the non-CA group were enrolled. Kaplan-Meier survival analysis indicated that CA was not associated with overall survival (p = 0.454) and disease-free survival (p = 0.163). In patients with stage III right colon cancer, there were no significant differences in overall survival (p = 0.501) and disease-free survival (p = 0.254). CONCLUSIONS: Pathological T stage, number of retrieved lymph nodes, and left side dissection along the superior mesenteric artery were independent risk factors for CA after laparoscopic D3 lymphadenectomy. CA does not impair the oncological outcomes of patients.

Application Value of 4K High-Definition System in Laparoscopic Gastrectomy: Preliminary Results and Initial Experience.

Background: To investigate the application value of 4K high definition (HD) in laparoscopic gastrectomy by comparing the short-term outcomes and subjective perception with three-dimensional (3D) and HD vision systems. Materials and Methods: A retrospective study was conducted between September 2018 and February 2019; a total of 87 patients who underwent laparoscopic gastrectomy were enrolled and divided into three groups in terms of different type of vision system used for surgery: 4K, 3D, and HD. Demographic and clinicopathological data as well as short-term outcomes were collected and analyzed. A questionnaire survey was completed by the team of surgeons to evaluate the subjective perception of different vision systems. Results: There was no significant difference in gender, body mass index, age, American Society of Anesthesiologists (ASA) score and history of abdominal surgery, tumor location as well as type of operation, and anastomosis between the 4K, 3D, and HD groups. All patients underwent laparoscopic gastrectomy without conversion to laparotomy. There was no difference between the three groups regarding operation time (4K versus 3D versus two-dimensional (2D), 183.60 ± 52.5 versus 189.69 ± 69.87 versus 211.00 0 ± 49.33, P = .145) and estimated blood loss (4K versus 3D versus 2D, 123.60 ± 119.51 versus 150.62 ± 105.46 versus 129.00 ± 103.57, P = .602), no difference was found in time to first flatus and postoperative hospital stay between the three groups. No significant difference was found in postoperative complications between the three groups. As for pathological results, there was no difference in tumor size and tumor-node-metastasis (TNM) stage. In 4K group, the number of lymph node harvested was 32.60 ± 10.28, no difference was found compared with that of 3D (29.81 ± 8.94) and HD groups (27.69 ± 10.96). The score of group 3D was the lowest concerning asthenopia and motion sickness. On the contrary, 3D group achieved the highest score in topographical orientation and depth description. 4K group was graded the highest in terms of control co-ordination of visual angle, visual acuity, radiance, resolution ratio and frames, and refresh rate. HD group was graded significantly lower in sense of control compared with that of 4K and 3D group. No significant difference was found in color resolution and contrast. Conclusions: In conclusion, the short-term effect of 4K HD laparoscopic system is comparable with that of HD and 3D laparoscopy, whereas 4K could reduce adverse effect than traditional instrument and improve quality of surgery. The Clinical Trial Registration number is NCT01441336.

A greater lymph node yield is required during pathological examination in microsatellite instability-high gastric cancer.

BACKGROUND: The impact of microsatellite status on lymph node (LN) yield during lymphadenectomy and pathological examination has never been assessed in gastric cancer (GC). In this study, we aimed to appraise the association between microsatellite instability-high (MSI-H) and LN yield after curative gastrectomy. METHODS: We retrospectively analyzed 1757 patients with GC undergoing curative gastrectomy and divided them into two groups: MSI-H (n = 185(10.5%)) and microsatellite stability (MSS) (n = 1572(89.5%)), using a five-Bethesda-marker (NR-24, BAT-25, BAT-26, CAT-25, MONO-27) panel. The median LN count and the percentage of specimens with a minimum of 16 LNs (adequate LN ratio) were compared between the two groups. The log odds (LODDS) of positive LN count (PLNC) to negative LN count (NLNC) and the target LN examined threshold (TLNT(x%)) were calculated in both groups. RESULTS: Statistically significant differences were found in the median LN count between MSI-H and MSS groups for the complete cohort (30 vs. 28, p = 0.031), for patients undergoing distal gastrectomy (DG) (30 vs. 27, p = 0.002), for stage II patients undergoing DG (34 vs. 28, p = 0.005), and for LN-negative patients undergoing DG (28 vs. 24, p = 0.002). MSI-H was an independent factor for higher total LN count in patients undergoing DG (p = 0.011), but it was not statistically correlated to the adequate LN ratio. Statistically significant differences in PLNC, NLNC and LODDS were found between MSI-H GC and MSS GC (all p < 0.001). The TLNT(90%) for MSI-H and MSS groups were 31 and 25, respectively. TLNT(X%) of MSI-H GC was always higher than that of MSS GC regardless of the given value of X%. CONCLUSIONS: MSI-H was associated with higher LN yield in patients undergoing gastrectomy for GC. Although MSI-H did not affect the adequacy of LN harvest, we speculate that a greater lymph node yield is required during pathological examination in MSI-H GC.

Prognostic value of apical lymph node metastasis at the inferior mesenteric artery in sigmoid and rectal cancer patients who undergo laparoscopic surgery.

BACKGROUND AND OBJECTIVES: Evidence supporting the importance of apical lymph nodes (LNs) and the potential long-term impact of LN metastases at the inferior mesenteric artery (IMA) lymphectomy remains limited. This study aimed to evaluate the prognostic value of LNs at the IMA (IMA-LN) in sigmoid and rectal cancer patients undergoing laparoscopic surgery. METHODS: We retrospectively evaluated 265 consecutive patients who underwent laparoscopic sigmoid or rectal cancer surgery between August 2016 and May 2020. They were divided into two groups according to the pathological results of the IMA LNs: IMA-LN negative (n = 248) and IMA-LN positive (n = 17). RESULTS: The IMA-LN negative group had significantly better overall survival (OS) (p = .020) and disease-free survival (DFS) (p = .000) than did the IMA-LN positive group. IMA-LN metastasis was associated with worse OS and DFS regardless of the pN stage. Patients with IMA-LN metastasis had a higher risk of postoperative recurrence, especially liver (p = .000) and lung (p = .025) metastasis, than did those without metastasis. However, there was no significant difference in the local recurrence rate between the two groups. CONCLUSIONS: IMA-LN metastasis is an independent risk factor for poor prognosis in sigmoid and rectal cancer. Dissecting and evaluating IMA-LN separately is a more accurate and practical method for predicting prognosis.

Impact of microsatellite status on negative lymph node count and prognostic relevance after curative gastrectomy.

BACKGROUND AND OBJECTIVES: The impact of microsatellite instability-high (MSI-H) phenotype on lymph node yield after lymphadenectomy has never been discussed in gastric cancer (GC). In this study, we aimed to assess the association of microsatellite status with negative lymph node count (NLNC) as well as its prognostic value. METHODS: We retrospectively analyzed 1491 GC patients and divided them into two groups: MSI-HGC (n = 141 [9.5%]) and microsatellite stability (MSSGC ) (n = 1350 [90.5%]). The NLNC and survival data were compared between the two groups. The log odds of positive lymph nodes (LNs) to negative LNs and the target lymph node examined threshold (TLNT) were calculated in both groups. RESULTS: A statistically significant difference was found in median NLNC (26 vs. 23, p < .001) between MSI-HGC and MSSGC patients. MSI status was an independent factor for NLNC (p < .001). NLNC showed positive prognostic value for cases with metastatic lymph node (LN+ ) in both MSI-HGC and MSSGC groups. The TLNT(90%) for MSI-HGC and MSSGC were 33 and 26, respectively. CONCLUSIONS: MSI-HGC was associated with higher NLNC in GC patients and this was independent of the presence of LN+ . However, more LNs are needed during pathological examination to capture LN+ cases in MSI-HGC.

Pelvic peritoneum closure reduces postoperative complications of laparoscopic abdominoperineal resection: 6-year experience in single center.

BACKGROUND: To investigate feasibility of laparoscopic abdominoperineal resection with pelvic peritoneum closure (LAPR-PPC) for lower rectal cancer. METHODS: LAPR-PPC has been used for lower rectal cancer in our institution since 2014. In this study, we retrospectively analyzed the data from 86 patients who underwent LAPR-PPC and compared with the data from 96 patients who underwent laparoscopic APR without PPC (LAPR) from January 2013 to December 2018. RESULTS: The rate of perineal surgical site infection (SSI) (18.75% (18/96) vs. 5.81% (5/86), p < 0.01), delayed (> 4 weeks) perineal healing (12.50% (12/96) vs. 3.49% (3/86), p = 0.027), ileus (7.29% (7/96) vs 1.16% (1/86), p = 0.044), and postoperative perineal hernia (PPH, 5.21% (5/96) vs. 0% (0/86), p = 0.032) were significantly lower in LAPR-PPC group than LAPR group. The patients in LAPR-PPC group had shorter hospitalization time (21.32 ± 11.95 days vs. 13.93 ± 11.51 days, p < 0.01). CONCLUSIONS: PPC procedure enabled the reduction in perineal wound complications, ileus, PPH, and consequently shortened hospitalization time. LAPR-PPC is beneficial for the patients with lower rectal cancer.

Detection of Microsatellite Instability from Circulating Tumor DNA by Targeted Deep Sequencing.

Currently, microsatellite instability (MSI) detection is limited to tissue samples with sufficient tumor content. Detection of MSI from blood has been explored but confounded by low sensitivity due to limited circulating tumor DNA (ctDNA). We developed a next-generation sequencing-based algorithm, blood MSI signature enrichment analysis, to detect MSI from blood. Blood MSI signature enrichment analysis development involved three major steps. First, marker sites that can effectively distinguish high MSI (MSI-H) from microsatellite stable tumors were extracted. Second, MSI signature enrichment analysis was performed based on hypergeometric probability, under the null hypothesis that plasma samples have similar MSI-H and microsatellite stable read coverage patterns for particular marker sites as the white blood cells from the training data set. Finally, enrichment scores of marker sites were normalized, and all markers were collectively considered to determine the MSI status of a plasma sample. In vitro dilution experiments with cell lines and in silico simulation experiments based on mixtures of MSI-H plasma and paired white blood cell DNA demonstrated 98% sensitivity and 100% specificity at a minimum of 1% ctDNA and 91.8% sensitivity and 100% specificity with 0.4% ctDNA. An independent validation cohort of 87 colorectal cancer patients with orthogonal confirmation of MSI status of tissues confirmed performance, achieving 94.1% sensitivity (16/17) and 100% specificity (27/27) for samples with ctDNA >0.4%.

Microsatellite Status Affects Tumor Response and Survival in Patients Undergoing Neoadjuvant Chemotherapy for Clinical Stage III Gastric Cancer.

BACKGROUND: We assessed the association between microsatellite instability-high (MSI-H) and tumor response to neoadjuvant chemotherapy (NAC) as well as its prognostic relevance in patients with clinical stage III gastric cancer (cStage III GC). MATERIALS AND METHODS: The NAC + surgery and the control cohorts consisted of 177 and 513 cStage III GC patients, respectively. The clinical and pathological features were compared between patients with MSI-H [n=57 (8.3%)] and microsatellite stability or microsatellite instability-low (MSS/MSI-L) [n=633 (91.7%)]. Radiological and histological response to NAC were evaluated based on response evaluation criteria in solid tumors (RECIST) and tumor regression grade (TRG) systems, respectively. The log-rank test and Cox analysis were used to determine the survival associated with MSI status as well as tumor regression between the two groups in both NAC + surgery and the control cohorts. RESULTS: A statistically significant association was found between MSI-H and poor histological response to NAC (p=0.038). Significant survival priority of responders over poor-responders could only be observed in MSS/MSI-L but not in MSI-H tumors. However, patients with MSI-H had statistically significantly better survival compared to patients with MSS/MSI-L in both the NAC + surgery (hazard ratio=0.125, 95% CI, 0.017-0.897, p=0.037 ) and the control cohort (hazard ratio=0.479, 95% CI, 0.268-0.856, p=0.013). CONCLUSION: MSI-H was associated with poorer regression and better survival after NAC for cStage III GC. TRG evaluation had prognostic significance in MSS/MSI-L but not in MSI-H. Further studies are needed to assess the value of NAC for cStage III GC patients with MSI-H phenotype.