New definition of borderline resectable colorectal liver metastasis based on prognostic outcomes.

BACKGROUND: Although surgical resection is the curative treatment for colorectal liver metastases (CRLM), the efficacy of neoadjuvant chemotherapy (NAC) has been discussed due to recent remarkable advances in chemotherapy. The definition of borderline resectable (BR) is most important, where neoadjuvant chemotherapy should be administered. This study aimed to examine a new definition of BR CRLM based on the results of the treatment outcomes. METHODS: This study included 127 patients who underwent liver resection for CRLM after exclusion of conversion cases between April 2010 and December 2023. Upfront resection was performed for synchronous and single liver metastasis or metachronous liver metastases. NAC was administered for multiple synchronous liver metastases. In order to find a new definition of BR, we examined the prognostic factors obtained from the treatment outcomes. RESULTS: CA19-9 level > 37.0 was the only prognostic factor in the upfront group [hazard ratio (HR) 2.386, 95% CI, 1.583-4.769; p = 0.049]. in the NAC group, a maximum tumor diameter ˃3 cm (HR 2.248, 95% CI 1.038-4,867, p = 0.040), CA19-9 level > 37.0 (HR 2.239, 95% CI 1.044-4.800, p = 0.038), and a right-sided primary tumor in the colon (HR 2.770, 95% CI 1.284-5.988, p = 0.009) were identified as significant prognostic factors. CONCLUSIONS: In cases of CRLM, patients with CA19-9 levels > 37.0, or CA19-9 level with < 37.0 but with a primary tumor in the right colon or a maximum tumor diameter of > 3 cm can be defined as BR CRLM and should be treated with NAC.

Early Identification of Patients with Potential Failure of Nonoperative Management for Gastroduodenal Peptic Ulcer Perforation.

INTRODUCTION: We aimed to identify objective factors associated with failure of nonoperative management (NOM) of gastroduodenal peptic ulcer perforation (GDUP) and establish a scoring model for early identification of patients in whom NOM of GDUP may fail. METHODS: A total of 71 patients with GDUP were divided into NOM (cases of NOM success) and operation groups (cases requiring emergency operation or conversion from NOM to operation). Using logistic regression analysis, a scoring model was established based on the independent factors. The patients were stratified into low-risk and high-risk groups according to the scores. RESULTS: Of the 71 patients, 18 and 53 were in the NOM and operation groups, respectively. Ascites in the pelvic cavity on computed tomography (CT) and sequential organ failure assessment (SOFA) score at admission were identified as independent factors for NOM failure. The scoring model was established based on the presence of ascites in the pelvic cavity on CT and SOFA score ≥2 at admission. The operation rates for GDUP were 28.6% and 86.0% in the low-risk (score, 0) and high-risk groups (scores, 2 and 4), respectively. CONCLUSION: Our scoring model may help determine NOM failure or success in patients with GDUP and make decisions regarding initial treatment.

Development of a scoring model based on objective factors to predict gangrenous/perforated appendicitis.

BACKGROUND: The mortality rate of gangrenous/perforated appendicitis is higher than that of uncomplicated appendicitis. However, non-operative management of such patients is ineffective. This necessitates their careful exam at presentation to identify gangrenous/perforated appendicitis and aid surgical decision-making. Therefore, this study aimed to develop a new scoring model based on objective findings to predict gangrenous/perforated appendicitis in adults. METHODS: We retrospectively analyzed 151 patients with acute appendicitis who underwent emergency surgery between January 2014 and June 2021. We performed univariate and multivariate analyses to identify independent objective predictors of gangrenous/perforated appendicitis, and a new scoring model was developed based on logistic regression coefficients for independent predictors. Receiver operating characteristic (ROC) curve analysis and the Hosmer-Lemeshow test were performed to assess the discrimination and calibration of the model. Finally, the scores were classified into three categories based on the probability of gangrenous/perforated appendicitis. RESULTS: Among the 151 patients, 85 and 66 patients were diagnosed with gangrenous/perforated appendicitis and uncomplicated appendicitis, respectively. Using the multivariate analysis, C-reactive protein level, maximal outer diameter of the appendix, and presence of appendiceal fecalith were identified as independent predictors for developing gangrenous/perforated appendicitis. Our novel scoring model was developed based on three independent predictors and ranged from 0 to 3. The area under the ROC curve was 0.792 (95% confidence interval, 0.721-0.863), and the Hosmer-Lemeshow test showed a good calibration of the novel scoring model (P = 0.716). Three risk categories were classified: low, moderate, and high risk with probabilities of 30.9%, 63.8%, and 94.4%, respectively. CONCLUSIONS: Our scoring model can objectively and reproducibly identify gangrenous/perforated appendicitis with good diagnostic accuracy and help in determining the degree of urgency and in making decisions about appendicitis management.

Risk factors for postoperative disseminated intravascular coagulation in surgical patients with non-occlusive mesenteric ischemia.

PURPOSE: The prognostic impact of disseminated intravascular coagulation (DIC) in surgical patients with non-occlusive mesenteric ischemia (NOMI) is unclear. This study aimed to confirm the association between postoperative DIC and prognosis and to identify preoperative risk factors associated with postoperative DIC. METHODS: This retrospective study included 52 patients who underwent emergency surgery for NOMI between January 2012 and March 2022. Kaplan-Meier curve analysis with the log-rank test was used to compare 30-day survival and hospital survival between patients with and without postoperative DIC. In addition, univariable and multivariable logistic regression analyses were performed to identify the preoperative risk factors for postoperative DIC. RESULTS: The 30-day and hospital mortality rates were 30.8% and 36.5%, respectively, and the incidence rate of DIC was 51.9%. Compared to patients without DIC, patients with DIC showed significantly lower rates of 30-day survival (41.5% vs 96%, log-rank P < 0.001) and hospital survival (30.2% vs 86.4%, log-rank, P < 0.001). Logistic regression analyses showed that the Japanese Association for Acute Medicine (JAAM) DIC score (OR = 2.697; 95% CI, 1.408-5.169; P = 0.003) and Sequential Organ Failure Assessment (SOFA) score (OR = 1.511; 95% CI, 1.111-2.055; P = 0.009) were independent risk factors for postoperative DIC in surgical patients with NOMI. CONCLUSION: The development of postoperative DIC is a significant prognostic factor for 30-day and hospital mortalities in surgical patients with NOMI. In addition, the JAAM DIC score and SOFA score have a high discriminative ability for predicting the development of postoperative DIC.

Preoperative scoring system for prediction of extended resection during emergency surgery for acute appendicitis.

PURPOSE: Appendicectomy is the primary treatment for acute appendicitis. However, extended resection (ER) may be required in difficult cases. Preoperative prediction of ER may identify challenging cases but remains difficult. We aimed to establish a preoperative scoring system for ER prediction during emergency surgery for acute appendicitis. METHODS: This was a single-center retrospective study. Patients who underwent emergency surgery for acute appendicitis between January 2014 and December 2022 were included and divided into ER and appendicectomy groups. Independent variables associated with ER were identified using multivariate logistic regression analysis. A new scoring system was established based on these independent variables. The discrimination of the new scoring system was assessed using the area under the receiver operating characteristic curve (AUC). The risk categorization of the scoring system was also analyzed. RESULTS: Of the 179 patients in this study, 12 (6.7%) underwent ER. The time interval from symptom onset to surgery ≥ 4 days, a retrocecal or retrocolic appendix, and the presence of an abscess were identified as independent preoperative predictive factors for ER. The new scoring system was established based on these three variables, and the scores ranged from 0 to 6. The AUC of the scoring system was 0.877, and the rates of ER among patients in the low- (score, 0-2), medium- (score, 4), and high- (score, 6) risk groups were estimated to be 2.5%, 28.6%, and 80%, respectively. CONCLUSION: Our scoring system may help surgeons identify patients with acute appendicitis requiring ER and facilitate decision-making regarding treatment options.

Impact of atherosclerosis on the postoperative complications of colorectal surgery in older patients with colorectal cancer.

BACKGROUND: Atherosclerosis is associated with various comorbidities; nonetheless, its effect on the postoperative complications of colorectal surgery in older patients with colorectal cancer (CRC) remains unclear. This study aimed to evaluate the impact of atherosclerosis on the postoperative complications of colorectal surgery in older adults with CRC. METHODS: Patients aged ≥ 65 years who underwent surgery for CRC between April 2017 and October 2020 were enrolled. To evaluate atherosclerosis, we prospectively calculated the cardio-ankle vascular index (CAVI) measured by the blood pressure/pulse wave test and abdominal aortic calcification (AAC) score from computed tomography. Risk factors for Clavien-Dindo grade ≥ III postoperative complications were evaluated by univariate and logistic regression analyses. RESULTS: Overall, 124 patients were included. The mean CAVI value and AAC score were 9.5 ± 1.8 and 7.0 ± 8.0, respectively. Clavien-Dindo grade ≥ III postoperative complications were observed in 14 patients (11.3%). CAVI (odds ratio, 1.522 [95% confidence interval, 1.073-2.160], p = 0.019), AAC score (1.083 [1.009-1.163], p = 0.026); and operative time (1.007 [1.003-1.012], p = 0.001) were identified as risk factors for postoperative complications. Based on the optimal cut-off values of CAVI and AAC score, the probability of postoperative complications was 27.8% in patients with abnormal values for both parameters, which was 17.4 times higher than the 1.6% probability of postoperative complications in patients with normal values. CONCLUSIONS: Atherosclerosis, particularly that assessed using CAVI and AAC score, could be a significant predictor of postoperative complications of colorectal surgery in older adults with CRC.

Prediction model for irreversible intestinal ischemia in strangulated bowel obstruction.

BACKGROUND: Preoperatively diagnosing irreversible intestinal ischemia in patients with strangulated bowel obstruction is difficult. Therefore, this study aimed to establish a prediction model for irreversible intestinal ischemia in strangulated bowel obstruction. METHODS: We included 83 patients who underwent emergency surgery for strangulated bowel obstruction between January 2014 and March 2022. The predictors of irreversible intestinal ischemia in strangulated bowel obstruction were identified using logistic regression analysis, and a prediction model for irreversible intestinal ischemia in strangulated bowel obstruction was established using the regression coefficients. Receiver operating characteristic analysis and fivefold cross-validation was used to assess the model. RESULTS: The prediction model (range, 0-4) was established using a white blood cell count of ≥ 12,000/µL and the computed tomography value of peritoneal fluid that was ≥ 20 Hounsfield units. The areas of the receiver operating characteristic curve of the new prediction model were 0.814 and 0.807 after fivefold cross-validation. A score of ≥ 2 was strongly suggestive of irreversible intestinal ischemia in strangulated bowel obstruction and necessitated bowel resection (odds ratio = 15.938). The bowel resection rates for the prediction scores of 0, 2, and 4 were 15.2%, 66.7%, and 85.0%, respectively. CONCLUSION: Our model may help predict irreversible intestinal ischemia that necessitates bowel resection for strangulated bowel obstruction cases and thus enable surgeons to recognize the severity of the situation, prepare for deterioration of patients with progression of intestinal ischemia, and select the appropriate surgical procedure for treatment.

Prediction Model for Failure of Nonoperative Management of Uncomplicated Appendicitis in Adults.

BACKGROUND: Prediction of failure of nonoperative management (NOM) in uncomplicated appendicitis (UA) is difficult. This study aimed to establish a new prediction model for NOM failure in UA. METHODS: We included 141 adults with UA who received NOM as initial treatment. NOM failure was defined as conversion to operation during hospitalization. Independent predictors of NOM failure were identified using logistic regression analysis. A prediction model was established based on these independent predictors. Receiver operating characteristic (ROC) curve analysis and the Hosmer-Lemeshow test were used to assess the discrimination and calibration of the model, respectively, and risk stratification using the model was performed. RESULTS: Among 141 patients, NOM was successful in 120 and unsuccessful in 21. Male sex, maximal diameter of the appendix, and the presence of fecalith were identified as independent predictors of NOM failure for UA. A prediction model with scores ranging from 0 to 3 was established using the three variables (male sex, maximal diameter of the appendix ≥ 15 mm, and the presence of fecalith). The area under the ROC curve for the new prediction model was 0.778, and the model had good calibration (P = 0.476). A score of 2 yielded a sensitivity of 71.4% and a specificity of 90.8%. Patients were stratified into low (0-1), moderate (2), and high (3) risk categories, which had NOM rates of 5.2%, 47.1%, and 77.8%, respectively. CONCLUSIONS: Our prediction model may predict NOM failure in UA with good diagnostic accuracy and help surgeons select appropriate treatments.

New risk factors of postoperative complications in elective gastrointestinal surgery of elderly patients: a prospective cohort study.

BACKGROUND: Gastrointestinal surgery in elderly individuals presents unexpected postoperative complications. However, predicting postoperative complications in elderly patients undergoing gastrointestinal surgeries is challenging because of the lack of a reliable preoperative evaluation system. We aimed to prospectively evaluate three new preoperative assessment methods to predict the postoperative complications in elderly patients undergoing elective gastrointestinal surgery. Moreover, we aimed to identify new risk factors of postoperative complications in this patient group. METHODS: This prospective cohort study enrolled 189 patients (age ≥ 65 years) who underwent elective gastrointestinal surgery at Tokyo Medical University Hachioji Medical Center between April 2017 and March 2019. Assessments performed preoperatively included the biological impedance analysis for evaluating the skeletal muscle mass, the SF-8 questionnaire for evaluating the subjective health-related quality of life, and the blood pressure/pulse wave test for assessing arteriosclerosis. The risk factors for Clavien-Dindo Grade ≥ III postoperative complications were assessed using these new evaluation methods. RESULTS: Clavien-Dindo Grade ≥ III postoperative complications were observed in 28 patients (14.8%). Univariate and multivariate analyses identified male sex, low skeletal muscle mass, and cardio-ankle vascular index ≥ 10 (arteriosclerosis) as significant independent risk factors of developing Grade ≥ III complications. CONCLUSIONS: Male sex, low skeletal muscle mass, and arteriosclerosis were significant risk factors of postoperative complications in elderly patients undergoing elective gastrointestinal surgery. The obtained knowledge could be useful in identifying high-risk patients who require careful perioperative management.

[A Case of Left Transverse Colon Cancer Safely Resected Using Three-Dimensional CT Angiography and Indocyanine Green Fluorography].

A 77-year-old man was admitted to our hospital because of a positive occult blood test result and diagnosed as having left transverse colon cancer(cT2N0M0)on detailed examination. The patient underwent a sigmoidectomy for colon cancer 24 years previously. Three-dimensional(3D)-CT angiography was performed before the present operation. The left branch of the middle colic artery, which was independently branched, and the marginal artery of the colon were found to be supplying blood from the left side of the transverse colon to the anastomosis of the sigmoid colon. In addition, the root of the left branch of the middle colic artery arose from the caudal side of the first jejunal vein. Therefore, a left hemicolectomy was performed. In accordance with the preoperative simulation, we safely resected the left branch of the middle colic artery at the root. Intraoperative blood flow evaluation using indocyanine green(ICG)fluorography clearly displayed the demarcation of the oral blood flow and the point of anastomosis. No notable complications occurred after the surgery. The results of the pathological analyses indicated a pT1bN0M0 tumor stage. Therefore, we conclude that 3D-CT angiography and ICG fluorography are useful for performing safer operations for left transverse colon cancers.

Artificial intelligence may help in predicting the need for additional surgery after endoscopic resection of T1 colorectal cancer.

BACKGROUND AND STUDY AIMS: Decisions concerning additional surgery after endoscopic resection of T1 colorectal cancer (CRC) are difficult because preoperative prediction of lymph node metastasis (LNM) is problematic. We investigated whether artificial intelligence can predict LNM presence, thus minimizing the need for additional surgery. PATIENTS AND METHODS: Data on 690 consecutive patients with T1 CRCs that were surgically resected in 2001 - 2016 were retrospectively analyzed. We divided patients into two groups according to date: data from 590 patients were used for machine learning for the artificial intelligence model, and the remaining 100 patients were included for model validation. The artificial intelligence model analyzed 45 clinicopathological factors and then predicted positivity or negativity for LNM. Operative specimens were used as the gold standard for the presence of LNM. The artificial intelligence model was validated by calculating the sensitivity, specificity, and accuracy for predicting LNM, and comparing these data with those of the American, European, and Japanese guidelines. RESULTS: Sensitivity was 100 % (95 % confidence interval [CI] 72 % to 100 %) in all models. Specificity of the artificial intelligence model and the American, European, and Japanese guidelines was 66 % (95 %CI 56 % to 76 %), 44 % (95 %CI 34 % to 55 %), 0 % (95 %CI 0 % to 3 %), and 0 % (95 %CI 0 % to 3 %), respectively; and accuracy was 69 % (95 %CI 59 % to 78 %), 49 % (95 %CI 39 % to 59 %), 9 % (95 %CI 4 % to 16 %), and 9 % (95 %CI 4 % - 16 %), respectively. The rates of unnecessary additional surgery attributable to misdiagnosing LNM-negative patients as having LNM were: 77 % (95 %CI 62 % to 89 %) for the artificial intelligence model, and 85 % (95 %CI 73 % to 93 %; P < 0.001), 91 % (95 %CI 84 % to 96 %; P < 0.001), and 91 % (95 %CI 84 % to 96 %; P < 0.001) for the American, European, and Japanese guidelines, respectively. CONCLUSIONS: Compared with current guidelines, artificial intelligence significantly reduced unnecessary additional surgery after endoscopic resection of T1 CRC without missing LNM positivity.

Impact of obesity on short- and long-term outcomes of laparoscopy assisted distal gastrectomy for gastric cancer.

BACKGROUND: Laparoscopy assisted distal gastrectomy (LADG) for gastric cancer has been rapidly adopted for the treatment of both early and advanced gastric cancers which need lymph node dissection, but remains difficult procedure, especially in patients with obesity. We evaluated the impact of obesity on short- and long-term outcomes of LADG for gastric cancer. METHODS: We retrospectively investigated 243 patients who underwent LADG for gastric cancer between January 2007 and December 2014. The patients were classified based on their body mass index (BMI) into the Obese (BMI ≥ 25) and Non-Obese (BMI < 25) Groups. Patient characteristics, clinicopathologic and operative findings, and short- and long-term outcomes were investigated and compared between the groups. RESULTS: The groups did not differ in age, sex, American Society of Anesthesiologists score, the presence of comorbidities, or pathologic stage. Operative time (265 ± 46.6 vs. 244 ± 55.6 min; P = 0.007) and estimated blood loss (113 ± 101.4 vs. 66.5 ± 95.2 ml; P = 0.007) were greater in the Obese Group. Fewer lymph nodes were retrieved in the Obese Group (38 ± 23.7 vs. 47.5 ± 24.3; P = 0.004). No differences were evident in postoperative complication rate (20% vs. 17%; P = 0.688) or the duration of postoperative hospital stay (9 ± 8.5 vs. 9 ± 5.1 days; P = 0.283) between the two groups. In the Obese Group, the 5-year overall survival rate was significantly lower than in the Non-Obese Group (67.6% vs. 90.3%; P = 0.036). Furthermore, 5-year disease-specific survival was significantly lower in the Obese Group than in the Non-Obese Group (72.7% vs. 94.9%; P = 0.015). CONCLUSIONS: LADG in patients with obesity could be performed as safe as in patients without obesity, with comparable postoperative results. But obesity may be a poor prognostic factor in gastric cancer.

Safety and curability of laparoscopic gastrectomy in elderly patients with gastric cancer.

BACKGROUND: Elderly patients are often considered as a high-risk population for major abdominal surgery due to reduced functional reserve and increased comorbidities. The aim of this study was to assess the safety and curability of laparoscopic gastrectomy in elderly patients with gastric cancer compared with short- and long-term outcomes in non-elderly patients. METHODS: We retrospectively investigated 386 patients who underwent laparoscopic gastrectomy for gastric cancer between January 2007 and December 2015 at the Digestive Disease Center, Showa University, Northern Yokohama Hospital. We categorized the patients into two groups by age: the elderly patients (≥ 75 years old) and the non-elderly patients (< 74 years old). Patient characteristics, clinicopathologic and operative findings, and short- and long-term outcomes were investigated and compared between the two groups. RESULTS: The elderly group showed a significantly higher rate of comorbidities (73.1 vs. 49.2%, P < 0.001), and American Society of Anesthesiologists (ASA) scores ≥ 2 (76.3 vs. 43.7%, P < 0.001), and using anticoagulant agents (25.8 vs. 7.9%, P < 0.001) than the non-elderly group. The postoperative morbidity and mortality did not differ between the two groups (19.4 vs. 18.8%; P = 0.880, 2.2 vs. 0%; P = 0.058). In the multivariate analysis, male sex was the only risk factor for postoperative morbidity after laparoscopic gastrectomy. However, age was not found to be a risk factor. The 5-year overall survival ratio was significantly lower in the elderly group than in the non-elderly group (67.7 vs. 85.0%; P < 0.001). However, the 5-year disease-specific survival ratio was similar in the two groups (84.8 vs. 89.1%; P = 0.071). CONCLUSION: Laparoscopic gastrectomy for gastric cancer could be safely performed in elderly patients with acceptable postoperative morbidity and curability.

Accuracy of diagnosing invasive colorectal cancer using computer-aided endocytoscopy.

Background and study aims Invasive cancer carries the risk of metastasis, and therefore, the ability to distinguish between invasive cancerous lesions and less-aggressive lesions is important. We evaluated a computer-aided diagnosis system that uses ultra-high (approximately × 400) magnification endocytoscopy (EC-CAD). Patients and methods We generated an image database from a consecutive series of 5843 endocytoscopy images of 375 lesions. For construction of a diagnostic algorithm, 5543 endocytoscopy images from 238 lesions were randomly extracted from the database for machine learning. We applied the obtained algorithm to 200 endocytoscopy images and calculated test characteristics for the diagnosis of invasive cancer. We defined a high-confidence diagnosis as having a ≥ 90 % probability of being correct. Results Of the 200 test images, 188 (94.0 %) were assessable with the EC-CAD system. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were 89.4 %, 98.9 %, 94.1 %, 98.8 %, and 90.1 %, respectively. High-confidence diagnosis had a sensitivity, specificity, accuracy, PPV, and NPV of 98.1 %, 100 %, 99.3 %, 100 %, and 98.8 %, respectively. Conclusion: EC-CAD may be a useful tool in diagnosing invasive colorectal cancer.

Fecal Volume after Laparoscopic Low Anterior Resection Predicts Anastomotic Leakage.

BACKGROUND/AIM: Anastomotic leakage (AL) is a major complication after laparoscopic low anterior resection (Lap-LAR). Many surgeons encounter AL following severe postoperative diarrhea. However, little is known about the relationship between postoperative fecal volume and AL. This study determined whether postoperative fecal volume can predict AL. METHODS: A retrospective assessment was performed with data from 176 patients with rectal cancers who underwent Lap-LAR between April 2011 and August 2015. A transanal tube was routinely placed in all cases. The fecal volume from the transanal tube was measured daily. The total fecal volume for 3 days after surgery was compared between the AL and non-AL groups. RESULTS: AL occurred in 11 patients. There were 3 patients with a fecal volume ≥1,000 mL for 3 days after surgery. AL occurred in these 3 patients. In patients with a fecal volume <1,000 mL, the total fecal volume was significantly greater in the AL group than that in the non-AL group (p = 0.0003). The cut-off value of the total fecal volume in AL was 118 mL. CONCLUSIONS: The volume of fecal discharge for 3 days after surgery is associated with the incidence of AL, and a fecal volume ≥118 mL may be a reliable predictor for AL.

Practical problems of measuring depth of submucosal invasion in T1 colorectal carcinomas.

PURPOSE: Submucosal invasion depth (SID) in colorectal carcinoma (CRC) is an important factor in estimating risk of lymph node metastasis, but can be difficult to measure, leading to inadequate or over-extensive treatment. Here, we aimed to clarify the practical aspects of measuring SID in T1 CRC. METHODS: We investigated 568 T1 CRCs that were resected surgically at our hospital from April 2001 to December 2013, and relationships between SID and clinicopathological factors, including the means of measurement, lesion morphology, and lymph node metastasis. RESULTS: Of these 568 lesions, the SID was ≥1000 µm in 508 lesions. SIDs for lesions measured from the surface layer were all ≥1000 µm. Although lesions with SIDs ≥1000 µm were associated with significantly higher levels of unfavorable histologic types and lymphovascular infiltration than shallower lesions, a depth of ≥1000 µm was not a significant risk factor for lymph node metastasis (LNM) (6.7 vs. 9.8 %; P = 0.64), and no lesions for which the sole pathological factor was SID ≥1000 µm had lymph node metastasis. Protruded lesions showed deeper SIDs than other types. CONCLUSIONS: Although we found several problems of measuring SID in this study, we also found, surprisingly, that SID is not a risk factor for lymph node metastasis, and its measurement is not needed to estimate the risk of lymph node metastasis.

Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis.

BACKGROUND AND AIM: Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection. METHODS: Initial or additional surgery with nodal dissection was performed in 653 T1 carcinoma cases. Clinicopathological factors were retrospectively analyzed with respect to nodal metastasis. The status of the muscularis mucosae (MM grade) was defined as grade 1 (maintenance) or grade 2 (fragmentation or disappearance). The lesions were then stratified based on the risk of nodal metastasis. RESULTS: Muscularis mucosae grade was associated with nodal metastasis (P = 0.026), and no patients with MM grade 1 lesions had nodal metastasis. Significant risk factors for nodal metastasis in patients with MM grade 2 lesions were attribution of women (P = 0.006), lymphovascular infiltration (P < 0.001), tumor budding (P = 0.045), and poorly differentiated adenocarcinoma or mucinous carcinoma (P = 0.007). Nodal metastasis occurred in 1.06% of lesions without any of these pathological factors, but in 10.3% and 20.1% of lesions with at least one factor in male and female patients, respectively. There was good inter-observer agreement for MM grade evaluation, with a kappa value of 0.67. CONCLUSIONS: Stratification using MM grade, pathological factors, and patient sex provided more appropriate indication for additional surgery with lymph node dissection after endoscopic treatment for T1 colorectal carcinomas.

'Head Invasion' Is Not a Metastasis-Free Condition in Pedunculated T1 Colorectal Carcinomas Based on the Precise Histopathological Assessment.

BACKGROUND/AIM: Previous reports stated that pedunculated T1 colorectal carcinomas with 'head invasion' showed almost no nodal metastasis, requiring endoscopic treatment alone. However, clinically, some lesions develop nodal metastasis. We aimed to validate the necessity of distinguishing between 'pedunculated' and 'non-pedunculated' lesions, and also between 'head' and 'stalk' invasions. METHODS: Initial or additional surgery with lymph node dissection was performed in 76 pedunculated and 594 non-pedunculated cases. Among pedunculated lesions, the baseline was defined as the junction line between normal and neoplastic epithelium (Haggitt's level 2). The degree of invasion was classified as 'head invasion' (above the baseline) or 'stalk invasion' (beyond the baseline). Clinicopathological factors were analyzed with respect to nodal metastasis. RESULTS: Nine of 76 (11.8%) pedunculated cases and 52/594 (8.8%) non-pedunculated cases developed nodal metastasis (p = 0.40). No significant differences were found in the rate of nodal metastasis between 'head invasion' (4/30, 13.3%) and 'stalk invasion' (5/46, 10.9%). All the 4 cases with 'head invasion' had at least one pathological factor. CONCLUSIONS: 'Head invasion' was not a metastasis-free condition. Even for pedunculated T1 cancers with 'head invasion', additional surgery with lymph node dissection should be considered if these have pathological risk factors.

Positive detection of exfoliated colon cancer cells on linear stapler cartridges was associated with depth of tumor invasion and preoperative bowel preparation in colon cancer.

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

Efficacy of transanal tube for prevention of anastomotic leakage following laparoscopic low anterior resection for rectal cancers: a retrospective cohort study in a single institution.

BACKGROUND: Anastomotic leakage is one of the most serious complications following laparoscopic low anterior resection (LAR) for rectal cancers. The purpose of this study was to investigate whether transanal tube placement can reduce anastomotic leakage following laparoscopic LAR. METHODS: Retrospective assessment was performed on 205 patients with rectal cancers who underwent laparoscopic LAR. A transanal tube was placed after anastomosis in 96 patients (group A). Another 109 patients were operated on without a transanal tube (group B). Clinicopathological and operative variables, the frequencies of anastomotic leakage and re-operation after leakage were investigated. RESULTS: Patient age, gender, body mass index, tumor size, Dukes' stage, intra-operative blood loss, and the rate of left colic artery preservation were comparable between the two groups. Tumor location was lower and operative time was significantly longer in group A than group B (p < 0.001). Overall rate of leakage was 9.3 % (19/205). The frequency of leakage was 4.2 % (4/96) in group A and was 13.8 % (15/109) in group B. The rate of leakage was significantly lower in group A (p < 0.05). Furthermore, the re-operation rate for symptomatic anastomotic leakage was 0 % (0/4) in group A, while in contrast it was 73.3 % (10/15) in group B. The rate of re-operation was lower in group A than group B (p < 0.05) and all cases with symptomatic leakage in group A were cured by conservative treatment. CONCLUSIONS: Transanal tube placement was effective for prevention of anastomotic leakage following laparoscopic LAR and avoiding re-operation after symptomatic leakage.