Deep learning imaging phenotype can classify metabolic syndrome and is predictive of cardiometabolic disorders.

BACKGROUND: Cardiometabolic disorders pose significant health risks globally. Metabolic syndrome, characterized by a cluster of potentially reversible metabolic abnormalities, is a known risk factor for these disorders. Early detection and intervention for individuals with metabolic abnormalities can help mitigate the risk of developing more serious cardiometabolic conditions. This study aimed to develop an image-derived phenotype (IDP) for metabolic abnormality from unenhanced abdominal computed tomography (CT) scans using deep learning. We used this IDP to classify individuals with metabolic syndrome and predict future occurrence of cardiometabolic disorders. METHODS: A multi-stage deep learning approach was used to extract the IDP from the liver region of unenhanced abdominal CT scans. In a cohort of over 2,000 individuals the IDP was used to classify individuals with metabolic syndrome. In a subset of over 1,300 individuals, the IDP was used to predict future occurrence of hypertension, type II diabetes, and fatty liver disease. RESULTS: For metabolic syndrome (MetS) classification, we compared the performance of the proposed IDP to liver attenuation and visceral adipose tissue area (VAT). The proposed IDP showed the strongest performance (AUC 0.82) compared to attenuation (AUC 0.70) and VAT (AUC 0.80). For disease prediction, we compared the performance of the IDP to baseline MetS diagnosis. The models including the IDP outperformed MetS for type II diabetes (AUCs 0.91 and 0.90) and fatty liver disease (AUCs 0.67 and 0.62) prediction and performed comparably for hypertension prediction (AUCs of 0.77). CONCLUSIONS: This study demonstrated the superior performance of a deep learning IDP compared to traditional radiomic features to classify individuals with metabolic syndrome. Additionally, the IDP outperformed the clinical definition of metabolic syndrome in predicting future morbidities. Our findings underscore the utility of data-driven imaging phenotypes as valuable tools in the assessment and management of metabolic syndrome and cardiometabolic disorders.

Genome-wide polygenic risk scores for hypertensive disease during pregnancy can also predict the risk for long-term cardiovascular disease.

BACKGROUND: Hypertensive disorders during pregnancy are associated with the risk of long-term cardiovascular disease after pregnancy, but it has not yet been determined whether genetic predisposition for hypertensive disorders during pregnancy can predict the risk for long-term cardiovascular disease. OBJECTIVE: This study aimed to evaluate the risk for long-term atherosclerotic cardiovascular disease according to polygenic risk scores for hypertensive disorders during pregnancy. STUDY DESIGN: Among UK Biobank participants, we included European-descent women (n=164,575) with at least 1 live birth. Participants were divided according to genetic risk categorized by polygenic risk scores for hypertensive disorders during pregnancy (low risk, score ≤25th percentile; medium risk, score 25th∼75th percentile; high risk, score >75th percentile), and were evaluated for incident atherosclerotic cardiovascular disease, defined as the new occurrence of one of the following: coronary artery disease, myocardial infarction, ischemic stroke, or peripheral artery disease. RESULTS: Among the study population, 2427 (1.5%) had a history of hypertensive disorders during pregnancy, and 8942 (5.6%) developed incident atherosclerotic cardiovascular disease after enrollment. Women with high genetic risk for hypertensive disorders during pregnancy had a higher prevalence of hypertension at enrollment. After enrollment, women with high genetic risk for hypertensive disorders during pregnancy had an increased risk for incident atherosclerotic cardiovascular disease, including coronary artery disease, myocardial infarction, and peripheral artery disease, compared with those with low genetic risk, even after adjustment for history of hypertensive disorders during pregnancy. CONCLUSION: High genetic risk for hypertensive disorders during pregnancy was associated with increased risk for atherosclerotic cardiovascular disease. This study provides evidence on the informative value of polygenic risk scores for hypertensive disorders during pregnancy in prediction of long-term cardiovascular outcomes later in life.

Development and validation of a novel strong prognostic index for colon cancer through a robust combination of laboratory features for systemic inflammation: a prognostic immune nutritional index.

BACKGROUND: Systemic inflammation is associated with survival outcomes in colon cancer. However, it is not well-known which systemic inflammatory marker is a powerful prognostic marker in patients with colon cancer. METHODS: A total of 4535 colon cancer patients were included in this study. We developed a novel prognostic index using a robust combination of seven systemic inflammation-associated blood features of the discovery set. The predictability and generality of the novel prognostic index were evaluated in the discovery, validation and replication sets. RESULTS: Among all combinations, the combination of albumin and monocyte count was the best candidate expression. The final formula of the proposed novel index is named the Prognostic Immune and Nutritional Index (PINI). The concordance index of PINI for overall and progression-free survival was the highest in the discovery, validation and replication sets compared to existing prognostic inflammatory markers. PINI was found to be a significant independent prognostic factor for both overall and progression-free survival. CONCLUSIONS: PINI is a novel prognostic index that has improved discriminatory power in colon cancer patients and appears to be superior to existing prognostic inflammatory markers. PINI can be utilised for decision-making regarding personalised treatment as the complement of the TNM staging system.

Dissecting the clinical relevance of polygenic risk score for obesity-a cross-sectional, longitudinal analysis.

BACKGROUND: Obesity is a global pandemic disease whose prevalence is increasing worldwide. The clinical relevance of a polygenic risk score (PRS) for obesity has not been fully elucidated in Asian populations. METHOD: We utilized a comprehensive health check-up database from the Korean population in conjunction with genotyping to generate PRS for BMI (PRS-BMI). We conducted a phenome-wide association (PheWAS) analysis and observed the longitudinal association of BMI with PRS-BMI. RESULTS: PRS-BMI was generated by PRS-CS. Adding PRS-BMI to a model predicting ten-year BMI based on age, sex, and baseline BMI improved the model's accuracy (p = 0.003). In a linear mixed model of longitudinal change in BMI with aging, higher deciles of PRS were directly associated with changes in BMI. In the PheWAS, significant associations were observed for metabolic syndrome, bone density, and fatty liver. In the lean body population, those having the top 20% PRS-BMI had higher BMI and body fat mass along with better metabolic trait profiles compared to the bottom 20%. A bottom-20% PRS-BMI was a risk factor for metabolically unhealthy lean body (odds ratio 3.092, 95% confidence interval 1.707-6.018, p < 0.001), with adjustment for age, sex and BMI. CONCLUSIONS: Genetic predisposition to obesity as defined by PRS-BMI was significantly associated with obesity-related disease or trajectory of obesity. Low PRS-BMI might be a risk factor associated with a metabolically unhealthy lean body. Better understanding the mechanisms of these relationships may allow tailored intervention in obesity or early selection of populations at risk of metabolic disease.

Multi-layered network-based pathway activity inference using directed random walks: application to predicting clinical outcomes in urologic cancer.

MOTIVATION: To better understand the molecular features of cancers, a comprehensive analysis using multi-omics data has been conducted. In addition, a pathway activity inference method has been developed to facilitate the integrative effects of multiple genes. In this respect, we have recently proposed a novel integrative pathway activity inference approach, iDRW and demonstrated the effectiveness of the method with respect to dichotomizing two survival groups. However, there were several limitations, such as a lack of generality. In this study, we designed a directed gene-gene graph using pathway information by assigning interactions between genes in multiple layers of networks. RESULTS: As a proof-of-concept study, it was evaluated using three genomic profiles of urologic cancer patients. The proposed integrative approach achieved improved outcome prediction performances compared with a single genomic profile alone and other existing pathway activity inference methods. The integrative approach also identified common/cancer-specific candidate driver pathways as predictive prognostic features in urologic cancers. Furthermore, it provides better biological insights into the prioritized pathways and genes in an integrated view using a multi-layered gene-gene network. Our framework is not specifically designed for urologic cancers and can be generally applicable for various datasets. AVAILABILITY AND IMPLEMENTATION: iDRW is implemented as the R software package. The source codes are available at https://github.com/sykim122/iDRW. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Long-term cardiovascular outcomes of gestational diabetes mellitus: a prospective UK Biobank study.

BACKGROUND: Previous studies showed that gestational diabetes mellitus (GDM) can be a risk factor for subsequent atherosclerotic cardiovascular disease. However, there is a paucity of information regarding diverse cardiovascular outcomes in elderly women after GDM. In the current study, we examined whether women with a history of GDM have an increased risk for long-term overall cardiovascular outcomes. METHODS: Among the UK participants, we included 219,330 women aged 40 to 69 years who reported at least one live birth. The new incidence of diverse cardiovascular outcomes was compared according to GDM history by multivariable Cox proportional hazard models. In addition, causal mediation analysis was performed to examine the contribution of well-known risk factors to observed risk. RESULTS: After enrollment, 13,094 women (6.0%) developed new overall cardiovascular outcomes. Women with GDM history had an increased risk for overall cardiovascular outcomes [adjusted HR (aHR) 1.36 (95% CI 1.18-1.55)], including coronary artery disease [aHR 1.31 (1.08-1.59)], myocardial infarction [aHR 1.65 (1.27-2.15)], ischemic stroke [aHR 1.68 (1.18-2.39)], peripheral artery disease [aHR 1.69 (1.14-2.51)], heart failure [aHR 1.41 (1.06-1.87)], mitral regurgitation [aHR 2.25 (1.51-3.34)], and atrial fibrillation/flutter [aHR 1.47 (1.18-1.84)], after adjustment for age, race, BMI, smoking, early menopause, hysterectomy, prevalent disease, and medication. In mediation analysis, overt diabetes explained 23%, hypertension explained 11%, and dyslipidemia explained 10% of the association between GDM and overall cardiovascular outcome. CONCLUSIONS: GDM was associated with more diverse cardiovascular outcomes than previously considered, and conventional risk factors such as diabetes, hypertension, and dyslipidemia partially contributed to this relationship.

Long-term Survival of 10,116 Korean Live Liver Donors.

OBJECTIVE: To evaluate the long-term mortality of Korean live liver donors using data from a national donor registry by comparing it with the mortality of the general population. SUMMARY OF BACKGROUND DATA: Although live liver donors generally have a healthy status, their long-term mortality has not been properly addressed in a large donor registry. METHODS: Data of 10,116 live liver donors were drawn from a mandated national registry of Korean live liver donors between 2000 and 2015. Matched controls were selected from the Korean National Health Insurance System-National Sample Cohort (NHIS-NSC). Median (range) follow-up of liver donors was 5.7 (0-15.9) years. Donors were 1:3 individually matched to controls by sex and 5-year age group; potential controls were from the whole NHIS-NSC (Control 1) or from NHIS-NSC after excluding people with contraindications to be organ donors (Control 2) (donor, n = 7538; Control 1, n = 28,248; Control 2, n = 28,248). RESULTS: Fifty-three deaths occurred after donation. Ten-year cumulative mortality of live liver donors was 0.9%. The most common cause of death was suicide (n = 19) followed by cancer (n = 9) and traffic accident (n = 7). In the matched control analysis, overall risk of death was significantly lower in donors than in Control 1 (P < 0.001), but higher than in Control 2 (P < 0.001). CONCLUSIONS: Liver donors have increased long-term mortality risk compared to similar healthy controls without contraindications to be organ donors. Therefore, long-term follow-up, including psychosocial support, is needed for live liver donors.

Liver imaging features by convolutional neural network to predict the metachronous liver metastasis in stage I-III colorectal cancer patients based on preoperative abdominal CT scan.

BACKGROUND: Introducing deep learning approach to medical images has rendered a large amount of un-decoded information into usage in clinical research. But mostly, it has been focusing on the performance of the prediction modeling for disease-related entity, but not on the clinical implication of the feature itself. Here we analyzed liver imaging features of abdominal CT images collected from 2019 patients with stage I - III colorectal cancer (CRC) using convolutional neural network (CNN) to elucidate its clinical implication in oncological perspectives. RESULTS: CNN generated imaging features from the liver parenchyma. Dimension reduction was done for the features by principal component analysis. We designed multiple prediction models for 5-year metachronous liver metastasis (5YLM) using combinations of clinical variables (age, sex, T stage, N stage) and top principal components (PCs), with logistic regression classification. The model using "1st PC (PC1) + clinical information" had the highest performance (mean AUC = 0.747) to predict 5YLM, compared to the model with clinical features alone (mean AUC = 0.709). The PC1 was independently associated with 5YLM in multivariate analysis (beta = - 3.831, P < 0.001). For the 5-year mortality rate, PC1 did not contribute to an improvement to the model with clinical features alone. For the PC1, Kaplan-Meier plots showed a significant difference between PC1 low vs. high group. The 5YLM-free survival of low PC1 was 89.6% and the high PC1 was 95.9%. In addition, PC1 had a significant correlation with sex, body mass index, alcohol consumption, and fatty liver status. CONCLUSION: The imaging features combined with clinical information improved the performance compared to the standardized prediction model using only clinical information. The liver imaging features generated by CNN may have the potential to predict liver metastasis. These results suggest that even though there were no liver metastasis during the primary colectomy, the features of liver imaging can impose characteristics that could be predictive for metachronous liver metastasis.

The association of genetic polymorphisms with nonalcoholic fatty liver disease in a longitudinal study.

BACKGROUND: Several genetic variants are known to be associated with nonalcoholic fatty liver disease (NAFLD). We aimed to evaluate the longitudinal associations between genetic variants and NAFLD. METHODS: We performed a genome-wide association study (GWAS) in Korean individuals who underwent repeated health check-ups. NAFLD was defined by ultrasonography and exclusion of secondary causes. RESULTS: The subjects had a median age of 50.0 years, and 54.8% were male. The median follow-up duration was 39 months. Among the 3905 subjects without NAFLD at baseline, 874 (22.4%) subjects developed NAFLD, and among the 1818 subjects with NAFLD at baseline, NAFLD regressed in 336 (18.5%) subjects during the follow-up period. After adjusting for age, sex and body mass index, no single-nucleotide polymorphism (SNP) passed Bonferroni correction for genome-wide significance in the development or regression of NAFLD. Among the SNPs that passed the genome-wide suggestiveness threshold (p = 1E-04) in the discovery set in the GWAS, only 1 SNP (rs4906353) showed an association with the development of NAFLD, with marginal significance in the validation set (p-value, discovery set = 9.68E-5 and validation set = 0.00531). CONCLUSIONS: This exploratory study suggests that longitudinal changes in NAFLD are not associated with genetic variants in the Korean population. These findings provide new insight into genetic mechanisms in the pathogenesis of NAFLD.

The exploration of feature extraction and machine learning for predicting bone density from simple spine X-ray images in a Korean population.

OBJECTIVE: Osteoporosis is hard to detect before it manifests symptoms and complications. In this study, we evaluated machine learning models for identifying individuals with abnormal bone mineral density (BMD) through an analysis of spine X-ray features extracted by deep learning to alert high-risk osteoporosis populations. MATERIALS AND METHODS: We retrospectively used data obtained from health check-ups including spine X-ray and dual-energy X-ray absorptiometry (DXA). Consecutively, we selected people with normal and abnormal bone mineral density. From the regions of interest of X-ray images, deep convolutional networks were used to generate image features. We designed prediction models for abnormal BMD using the image features trained by machine learning classification algorithms. The performances of each model were evaluated. RESULTS: From 334 participants, 170 images of abnormal (T scores < - 1.0 standard deviations (SD)) and 164 of normal BMD (T scores > = - 1.0 SD) were used for analysis. We found that a combination of feature extraction by VGGnet and classification by random forest based on the maximum balanced classification rate (BCR) yielded the best performance in terms of the area under the curve (AUC) (0.74), accuracy (0.71), sensitivity (0.81), specificity (0.60), BCR (0.70), and F1-score (0.73). CONCLUSION: In this study, we explored various machine learning algorithms for the prediction of BMD using simple spine X-ray image features extracted by three deep learning algorithms. We identified the combination for the best performance in predicting high-risk populations with abnormal BMD.

Upregulation of SLC2A3 gene and prognosis in colorectal carcinoma: analysis of TCGA data.

BACKGROUND: Upregulation of SLC2A genes that encode glucose transporter (GLUT) protein is associated with poor prognosis in many cancers. In colorectal cancer, studies reporting the association between overexpression of GLUT and poor clinical outcomes were flawed by small sample sizes or subjective interpretation of immunohistochemical staining. Here, we analyzed mRNA expressions in all 14 SLC2A genes and evaluated the association with prognosis in colorectal cancer using data from the Cancer Genome Atlas (TCGA) database. METHODS: In the present study, we analyzed the expression of SLC2A genes in colorectal cancer and their association with prognosis using data obtained from the TCGA for the discovery sample, and a dataset from the Gene Expression Omnibus for the validation sample. RESULTS: SLC2A3 was significantly associated with overall survival (OS) and disease-free survival (DFS) in both the discovery sample (345 patients) and validation sample (501 patients). High SLC2A3 expression resulted in shorter OS and DFS. In multivariate analyses, high SLC2A3 levels predicted unfavorable OS (adjusted HR 1.95, 95% CI 1.22-3.11; P = 0.005) and were associated with poor DFS (adjusted HR 1.85, 95% CI 1.10-3.12; P = 0.02). Similar results were found in the discovery set. CONCLUSION: Upregulation of the SLC2A3 genes is associated with decreased OS and DFS in colorectal cancer patients. Therefore, assessment of SLC2A3 gene expression may useful for predicting prognosis in these patients.

Incidence of Adhesive Bowel Obstruction After Colon Cancer Surgery and its Risk Factors: A Nationwide Claim Study.

OBJECTIVE: To elucidate the incidence of adhesive postoperative bowel obstruction (PBO) after colon cancer surgery and its risk factors using nationwide claim data. BACKGROUND: PBO has a significant impact on quality of life and medical costs after colectomy, though most of the literature consists of single-institution analyses. METHODS: Data from 24,645 patients who underwent regional colectomy for colon cancer from 2010 to 2012 and had at least 3 years of follow up were obtained from the Health Insurance Review and Assessment Service database. Patients who required nasogastric tube insertion or bowel obstruction surgery more than 30 days after index colectomy were defined as having PBO. RESULTS: A total of 3083 (12.5%) patients experienced at least one PBO episode within 3 years after surgery. Logistic regression analysis showed that significant risk factors for PBO were elderly (odds ratio, OR = 1.13), male (OR = 1.27), open colectomy (OR = 1.99), and low-volume institution (OR = 1.17). Among 3083 PBO patients, 50.7% experienced their 1st PBO during the 1st year after the index colectomy, and 7.8% experienced recurrence within 3 years after index colectomy. The 3-year cumulative incidences of PBO according to risk factors of elderly, male, open colectomy, and low-volume institution were 14.6%, 14.3%, 19.5%, and 15.1%, respectively. CONCLUSIONS: We report several independent risk factors for PBO and its incidence after regional colectomy for colon cancer. These results are informative for medical providers as patients who will or have had the procedure and could be useful baseline data for further research on the active prevention or treatment of PBO after colectomy.

The impact of visceral adipose tissue amount on the adequacy of lymph node retrieval in colorectal cancer surgery.

BACKGROUND: Obesity is increasing worldwide, potentially influencing surgical outcomes in colorectal cancer (CRC) patients. We analyzed the effects of obesity indexes on lymph node (LN) retrieval in CRC patients. METHOD: We applied obesity indexes of body mass index (BMI) and visceral (VAT) and subcutaneous (SAT) adipose tissue volumes to stage I-III CRC patients. The primary outcome was the effect of these indexes on the number of retrieved LNs (12 > LNs ≥ 12). RESULTS: Among 519 patients, 35.6% had a BMI ≥ 25 kg/m2 . After adjusting for gender, age, tumor location, resected colon length, and local invasion and LN statuses, patients in the highest VAT quartile showed a 5.848 decrease in the number of retrieved LNs, with an odds ratio of 0.483 (95% confidence interval [CI] 0.260-0.8979) for adequate LN retrieval (≥12), compared with those in the lowest quartile (P < 0.001 for both). Analysis of the model predicting LN retrieval revealed VAT as the only obesity index (area under the curve [AUC] = 0.721) providing significant additional predictive power (P = 0.037) to the model including age, gender, staging, tumor location, and resected colon length (AUC = 0.707). CONCLUSION: Increased VAT may cause inadequate LN retrieval in CRC patients. In viscerally obese patients, VAT volumes should be considered when clinically interpreting LN status.

Incidence of Clinically Relevant Incisional Hernia After Colon Cancer Surgery and Its Risk Factors: A Nationwide Claims Study.

BACKGROUND: As there is scant literature focusing on incisional hernia for which hospital care is sought, the aim of this study was to elucidate the incidence and risk factors of overt incisional hernia (OIH) after colon cancer surgery using nationwide claims data. METHODS: Claims data of colon cancer patients who underwent regional colectomy were obtained from the Health Insurance Review and Assessment Service database of South Korea. Data from 2010 to 2012 were collected to ensure adequate follow-up. OIH was considered to be present when either the diagnosis code for IH or the claim code for IH repair was entered after index colectomy for colon cancer. RESULTS: A total of 24,645 patients underwent regional colectomy for colon cancer during the study period. Of these, 376 (1.5%) patients had an OIH within 3 years after surgery, and 50.3% of OIHs developed within the first year after the index colectomy (883.7 cases/10,000 patient-years). The Cox proportional hazard model showed that age >65 years, female gender, open colectomy, and institution volume <100 colectomies per year were statistically significant risk factors for OIH. The 3-year cumulative OIH incidence rates according to age >65 years, female gender, open colectomy, and institution volume <100 colectomies per year were 2.1, 2.1, 2.0, and 2.1%, respectively. CONCLUSIONS: Several risk factors for OIH and its incidence after regional colectomy for colon cancer were identified. These findings are helpful for classifying patients undergoing segmental colectomy who have increased the likelihood of developing IH and are informative for patients and medical providers performing the surgery.

Prognostic Impact of Changes in Adipose Tissue Areas after Colectomy in Colorectal Cancer Patients.

There have been few studies assessing the changes in the body components of patients after colectomy in colorectal cancer (CRC). The purpose of this study was to verify the trends in the adipose tissue areas of CRC patients before and after surgery and to determine their clinical relevance. Computed tomography (CT)-assessed subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) areas were recorded before and after curative resection in stage I to III CRC patients. Changes in the adipose tissue were assessed by calculating the difference in the adipose tissue area between preoperative CT and the most recent postoperative CT, which is disease-free state. Regarding obesity before surgery, there were no prognostic effect of body mass index (BMI), VAT and SAT, and 47.3% of patients had increases in VAT after colectomy. By multivariate analysis, adjusting sex, age, stage, differentiation, VAT change was the only obesity related factor to predict the prognosis, that patients who had increase in VAT after colectomy had better overall survival (HR, 0.557; 95% CI, 0.317-0.880) and disease-free survival (HR, 0.602; 95% CI, 0.391-0.927). BMI and SAT change had no significant association. In subgroup analysis of stage III CRC patients, VAT change had significance for prognosis only in patients who had adjuvant chemotherapy but not in those who did not receive postoperative chemotherapy. Increase in visceral adipose tissue after surgery is a favorable predictor of prognosis for CRC patients.

Surgical outcomes and prognostic factors of emergency surgery for colonic perforation: would fecal contamination increase morbidity and mortality?

PURPOSE: Complications resulting from colonic perforation are related to secondary peritonitis due to bacterial or fecal contamination. We investigated outcomes of emergency surgery for colonic perforation associated with fecal contamination with regard to early and late postoperative complication rates and mortality rates, and investigated prognostic factors influencing those outcomes. METHODS: A retrospective analysis of prospectively collected data on factors influencing complications and mortality rates was conducted on data from 152 patients who had undergone emergent operations for colonic perforation between January 2005 and December 2011. Patients were categorized into two groups: those with and without gross fecal contamination at the time of operation. RESULTS: Forty-one (26.9 %) patients had gross fecal contamination. Patients who had fetal contamination had a higher Mannheim peritonitis index (31.3 ± 5.1 vs. 21.9 ± 7.2, p < 0.001), higher organ failure rate (53.7 vs. 24.3 %, p = 0.001), and longer operating time (168.8 ± 49.9 vs. 144.8 ± 66.1 min, p = 0.036) than patients without fecal contamination. Early complications (<30 days) occurred more frequently in the fecal contamination group (82.9 vs. 49.5 %, p = 0.001), although late complications (46.2 vs. 39.3 %, p = 0.942) and mortality (17.1 vs. 8.1 %, p = 0.110) did not differ. In multivariate analysis, fecal contamination significantly predicted early complications (odds ratio, 2.78; p = 0.037) but not late complications or mortality. CONCLUSIONS: The frequency of early complications can increase if fecal contamination exists. However, when early complications are well managed, fecal contamination does not significantly influence occurrences late complications or mortality.

Colonoscopic surveillance after colorectal cancer resection: who needs more intensive follow-up?

BACKGROUND/AIMS: Although there are guidelines for colonoscopic surveillance after colorectal cancer (CRC) surgery, the data evaluating the effectiveness of these guidelines are limited. We determined the risk factors for metachronous neoplasia (MN) by performing annual colonoscopy examinations after curative resection. METHODS: We performed annual colonoscopic surveillance on stage I-III CRC patients after curative resection. We stratified the patients based on the advanced neoplasia risk during the surveillance. RESULTS: Advanced MN detected was in 59 (13.1%) of 451 patients. Overall, the cumulative incidence of advanced MN was 17.3% at 5 years. By the multivariate analysis, the risk factors for advanced MN were male gender, age >65, left-sided index cancer and being in the high-risk group. The cumulative incidence of advanced MN was 38.9% at 5 years in the high-risk group. Among the patients who had advanced MN, secondary advanced MN was detected in 13 patients (22.0%) with a subsequent colonoscopy. The 2-year cumulative incidence of secondary advanced MN was 16.9%. Four (0.88%) patients had metachronous CRC during the surveillance and the interval from the index CRC was a median of 58.5 months. CONCLUSIONS: Although the current follow-up guidelines for colonoscopic surveillance after CRC are well established, the high-risk group calls for more meticulous follow-up, which should be continued for a sufficient time.

Electrophysiological and Mechanical Characteristics in Human Ileal Motility: Recordings of Slow Waves Conductions and Contractions, In vitro.

Little human tissue data are available for slow waves and migrating motor complexes, which are the main components of small bowel motility. We investigated the electrophysiological and mechanical characteristics of human ileal motility, in vitro. Ileum was obtained from patients undergoing bowel resection. Electrophysiological microelectrode recordings for membrane potential changes and mechanical tension recordings for contraction from smooth muscle strips and ileal segments were performed. Drugs affecting the enteric nervous system were applied to measure the changes in activity. Slow waves were detected with a frequency of 9~10/min. There were no cross-sectional differences in resting membrane potential (RMP), amplitude or frequency between outer and inner circular muscle (CM), suggesting that electrical activities could be effectively transmitted from outer to inner CM. The presence of the interstitial cell of Cajal (ICC) at the linia septa was verified by immunohistochemistry. Contractions of strips and segments occurred at a frequency of 3~4/min and 1~2/min, respectively. The frequency, amplitude and area under the curve were similar between CM and LM. In segments, contractions of CM were associated with LM, but propagation varied with antegrade and retrograde directions. Atropine, N(W)-oxide-L-arginine, and sodium nitroprusside exhibited different effects on RMP and contractions. There were no cross-sectional differences with regard to the characteristics of slow waves in CM. The frequency of contractions in smooth muscle strips and ileal segments was lower than slow waves. The directions of propagation were diverse, indicating both mixing and transport functions of the ileum.

Early postoperative small bowel obstruction is an independent risk factor for subsequent adhesive small bowel obstruction in patients undergoing open colectomy.

BACKGROUND: This prospective study was performed to investigate whether postoperative ileus (POI) or early postoperative small bowel obstruction (EPSBO) affects the development of adhesive small bowel obstruction (SBO) in patients undergoing colectomy. METHODS: We prospectively enrolled 1,002 patients who underwent open colectomy by a single surgeon. POI was defined as the absence of bowel function for more than 5 days or as a delay in oral intake beyond 7 days postoperatively. EPSBO was defined as the clinical and radiologic identification of SBO after resuming oral intake between postoperative days 7 and 30. Adhesive SBO was defined as SBO developing after 30 days because of intraperitoneal adhesion. The associations between POI, EPSBO, patient- and surgery-related variables, and the development of adhesive SBO were analyzed. RESULTS: A total of 85 (8.5 %) patients developed POI, and 42 patients (4.2 %) developed EPSBO, with seven patients experiencing both POI and EPSBO. During the follow-up period (median 51 months), 70 patients (7.0 %) developed adhesive SBO, six (8.6 %) of whom needed laparotomy. The occurrence of adhesive SBO was significantly higher in patients with EPSBO than in those without EPSBO (26.5 vs. 7.5 % at 5 years, P < 0.001), but not in patients with POI (13.4 vs. 7.8 % at 5 years, P = 0.158). Multivariable analysis showed colostomy (hazard ratio [HR] 2.530, P = 0.006) and EPSBO (HR 4.063, P < 0.001) as independent risk factors for adhesive SBO. CONCLUSIONS: The development of adhesive SBO after colectomy is more frequent in patients with EPSBO and colostomy; however, POI does not increase the risk of adhesive SBO.

The outcomes and prognostic factors of surgical treatment for ischemic colitis: what can we do for a better outcome?

BACKGROUND/AIMS: Surgical treatment is mandatory for severe ischemic colitis, but morbidity and mortality are high. We evaluated the outcomes and prognostic factors of surgical treatment for ischemic colitis. METHODOLOGY: Forty-nine consecutive patients (M:F, 26:23, median, 63 years), who underwent surgery for ischemic colitis by single surgeon, had been recruited prospectively and retrospectively analyzed. RESULTS: The causes of ischemia were vascular occlusions in 35 (71.4%). Thirty-seven (75.5%) patients had coexisting chronic medical problems. Emergency operation was performed in 40 (81.6%). Ischemic regions were right colon in 20 (40.8%), left colon in 19 (38.8%), and whole colon in 9 (18.4%). Resection with stoma formation was performed in 29 (59.2%) and primary anastomosis in 19 (38.8%). Postoperative morbidity occurred in 42 (85.7%) and mortality in 22 (44.9%). Univariate analysis showed that abdominal pain with peritoneal irritation signs, systemic inflammatory response, severe systemic hypotension, cardiovascular disease, vasoactive drug, emergency operation, and stoma formation were unfavorably associated with morbidity and/or mortality. Preoperative severe systemic hypotension was the only significant risk factor of mortality in multivariate analysis. CONCLUSIONS: Morbidity and mortality remained high in surgery for ischemic colitis. As preoperative systemic hypotension was the most important, early surgical treatment before the disease being deteriorated is mandatory.