Early-onset colorectal cancer (EOCRC) shows a different epidemiological trend compared to later-onset colorectal cancer, with its incidence rising in most regions and countries worldwide. However, the reasons behind this trend remain unclear. The etiology of EOCRC is complex and could involve both genetic and environmental factors. Apart from Lynch syndrome and Familial Adenomatous Polyposis, sporadic EOCRC exhibits a broad spectrum of pathogenic germline mutations, genetic polymorphisms, methylation changes, and chromosomal instability. Early-life exposures and environmental risk factors, including lifestyle and dietary risk factors, have been found to be associated with EOCRC risk. Meanwhile, specific chronic diseases, such as inflammatory bowel disease, diabetes, and metabolic syndrome, have been associated with EOCRC. Interactions between genetic and environmental risk factors in EOCRC have also been explored. Here we present findings from a narrative review of epidemiological studies on the assessment of early-life exposures, of EOCRC-specific environmental factors, and their interactions with susceptible loci. We also present results from EOCRC-specific genome-wide association studies that could be used to perform Mendelian randomization analyses to ascertain potential causal links between environmental factors and EOCRC.
Humans ; Colorectal Neoplasms/etiology* ; Risk Factors ; Genome-Wide Association Study ; Genetic Predisposition to Disease/genetics*

INTRODUCTION: Acute malignant large bowel obstruction (MBO) occurs in 8%-15% of colorectal cancer patients. Self-expandable metal stents (SEMS) have progressed from a palliative modality to use as bridge to surgery (BTS). We aimed to assess the safety and efficacy of SEMS for MBO in our institution. METHODS: The data of patients undergoing SEMS insertion for MBO were reviewed. Technical success was defined as successful SEMS deployment across tumour without complications. Clinical success was defined as colonic decompression without requiring further surgical intervention. Rates of complications, median time to surgery, types of surgery and rates of recurrence were studied. RESULTS: Seventy-nine patients underwent emergent SEMS placement from September 2013 to February 2020. Their mean age was 68.8 ± 13.8 years and 43 (54%) patients were male. Mean tumour length was 4.2 cm ± 2.2 cm; 89.9% of malignant strictures were located distal to the splenic flexure. Technical and clinical success was 94.9% and 98.7%, respectively. Perforation occurred in 5.1% of patients, with none having stent migration or bleeding. Fifty (63.3%) patients underwent SEMS insertion as BTS. Median time to surgery was 20 (range 6-57) days. Most (82%) patients underwent minimally invasive surgery. Primary anastomosis rate was 98%. Thirty-nine patients had follow-up beyond 1-year posttreatment (median 34 months). Local recurrence and distant metastasis were observed in 4 (10.3%) and 5 (12.8%) patients, respectively. CONCLUSION Insertion of SEMS for acute MBO has high success rates and a good safety profile. Most patients in this audit underwent minimally invasive surgery and primary anastomosis after successful BTS.
Humans ; Male ; Middle Aged ; Aged ; Aged, 80 and over ; Female ; Colorectal Neoplasms/pathology* ; Singapore ; Tertiary Care Centers ; Stents/adverse effects* ; Intestinal Obstruction/etiology* ; Treatment Outcome ; Retrospective Studies ; Palliative Care

For elective surgery of colorectal cancer, current evidence supports preoperative mechanical bowel preparation combined with oral antibiotics. Meanwhile, for patients with varied degrees of intestinal stenosis, individualized protocol is required to avoid adverse events. We hereby summarize recent high-quality evidences and updates of guidelines and consensus, and recommend stratified bowel preparation based on the clinical practice of our institute as follows. (1) For patients with unimpaired oral intake, whose tumor can be passed by colonoscopy, mechanical bowel preparation and oral antibiotics are given. (2) For patients without symptoms of bowel obstruction but with impaired oral intake or incomplete colonoscopy due to tumor-related stenosis, small-dosage laxative is given for several days before surgery, and oral antibiotics the day before surgery. (3) For patients with bowel obstruction, mechanical bowel preparation or enema is not indicated. We proposed this evidence-based, individualized protocol for preoperative bowel preparation for the reference of our colleagues, in the hope of improving perioperative outcomes and reducing adverse events.
Anti-Bacterial Agents/therapeutic use* ; Colorectal Neoplasms/drug therapy* ; Constriction, Pathologic/etiology* ; Elective Surgical Procedures/adverse effects* ; Humans ; Preoperative Care/methods* ; Surgical Wound Infection/etiology*

Objective: To compare the effects of three treatment options: emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery, on the pathological characteris- tics of surgically-resected specimens from patients with completely obstructive colorectal cancer. Methods: This was a retrospective cohort study analyzing clinicopathological data of patients with complete obstructive colorectal cancer who were admitted to the General Surgery Department of Beijing Chaoyang Hospital, Capital Medical University, between May 2012 and August 2020. The inclusion criteria were diagnosed with complete colorectal obstruction, pathologically confirmed as adenocarcinoma, resectable on imaging assessment, and without distant metastasis, combined with the patients' clinical manifestations and imaging examination findings. Patients with multiple colorectal cancers, refusal to undergo surgery, and concurrent peritonitis or intestinal perforation before stenting of the intestinal obstruction were excluded. Eighty-nine patients with completely obstructive colorectal cancer were enrolled in the study and were divided into emergency surgery group (n=30), stent-surgery group (n=34), and stent-neoadjuvant chemotherapy- surgery group (n=25) according to the treatment strategy. Differences in the pathological features (namely perineural infiltration, lymphovascular infiltration, tumor deposits, specimen intravascular necrosis, inflammatory infiltration, abscesses, mucus lake formation, foreign body giant cells, calcification, and tumor cell ratio) and biomolecular markers (namely cluster of differentiation (CD)34, Ki67, Bcl-2, matrix metalloproteinase-9, and hypoxia-inducible factor alpha) were recorded. Pathological evaluation was based on the presence or absence of qualitative evaluation of pathological features, such as peripheral nerve infiltration, vascular infiltration, and cancer nodules within the specimens. The evaluation criteria for the pathological features of the specimens were as follows: Semi-quantitative graded evaluation based on the proportion of tissue necrosis, inflammatory infiltrates, abscesses, mucus lake formation, foreign body giant cells, calcification, and tumor cells in the field of view within the specimen were classified as: grade 0: not seen within the specimen; grade 1: 0-25%; grade 2: 25%-50%; grade 3: 50%-75%; and grade 4: 75%-100%. The intensity of cellular immunity was classified as none (0 points), weak (1 point), moderate (2 points), and strong (3 points). The two evaluation scores were then multiplied to obtain a total score of 0-12. The immunohistochemical results were also evaluated comprehensively, and the results were defined as: negative (grade 0): 0 points; weakly positive (grade 1): 1-3 points; moderately positive (grade 2): 4-6 points; strongly positive (grade 3): 7-9 points; and very strong positive (grade 4): 10-12 points. Normally-distributed values were expressed as mean±standard deviation, and one-way analysis of variance was used to analyze the differences between the groups. Non-normally-distributed values were expressed as median (interquartile range: Q1, Q3). A nonparametric test (Kruskal-Wallis H test) was used for comparisons between groups. Results: The differences were not statistically significant when comparing the baseline data for age, gender, tumor site, American Society of Anesthesiologists score, tumor T-stage, N-stage, and degree of differentiation among the three groups (all P>0.05). The differences were not statistically significant when comparing the pathological characteristics of the resected tumor specimens, such as foreign body giant cells, inflammatory infiltration, and mucus lake formation among the three groups (all P>0.05). The rates of vascular infiltration were 56.6% (17/30), 41.2% (15/34), and 20.0% (5/25) in the emergency surgery, stent-surgery, and stent- neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences between the groups (χ²=7.142, P=0.028). Additionally, the rate of vascular infiltration was significantly lower in the stent-neoadjuvant chemotherapy-surgery group than that in the emergency surgery group (P=0.038). Peripheral nerve infiltration rates were 55.3% (16/30), 41.2% (14/34), and 16.0% (4/25), in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences (χ²=7.735, P=0.021). The infiltration peripheral nerve rates in the stent-neoadjuvant chemotherapy-surgery group were significantly lower than those in the emergency surgery group (P=0.032). The necrosis grade was 2 (1, 2), 2 (1, 3), and 2 (2, 3) in the emergency surgery, stent- surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences (H=10.090, P=0.006). Post hoc comparison revealed that the necrosis grade was higher in the stent-surgery and stent-neoadjuvant chemotherapy-surgery groups compared with the emergency surgery group (both P<0.05). The abscess grade was 2 (1, 2), 3 (1, 3), and 2 (2, 3) in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences (H=6.584, P=0.037). Post hoc comparison revealed that the abscess grade in the emergency surgery group was significantly lower than that in the stent-surgery group (P=0.037). The fibrosis grade was 2 (1, 3), 3 (2, 3), and 3 (2, 3), in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences (H=11.078, P=0.004). Post hoc analysis revealed that the fibrosis degree was higher in both the stent-surgery group and the stent- neoadjuvant chemotherapy-surgery group compared with the emergency surgery group (both, P<0.05). The tumor cell ratio grades were 4 (3, 4), 4 (3, 4), and 3 (2, 4), in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, with statistically significant differences (H=8.594, P=0.014). Post hoc analysis showed that the tumor cell ratio in the stent-neoadjuvant chemotherapy-surgery group was significantly lower than that in the emergency surgery group (P=0.012). The CD34 grades were 2 (2, 3), 3 (2, 4), and 3 (2, 3) in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups, respectively, and the difference was statistically significant (H=9.786, P=0.007). Post hoc analysis showed that the CD34 grades in the emergency surgery, stent-surgery, and stent-neoadjuvant chemotherapy-surgery groups were 2 (2, 3), 3 (2, 4), and 3 (2,3), respectively. Post hoc analysis revealed that the CD34 concentration was higher in the stent-surgery group than that in the emergency surgery group (P=0.005). Conclusion: Stenting may increase the risk of distant metastases in obstructive colorectal cancer. The stent-neoadjuvant chemotherapy-surgery treatment model promotes tumor cell necrosis and fibrosis and reduces the proportion of tumor cells, vascular infiltration, and peripheral nerve infiltration, which may help decrease local tumor infiltration and distant metastasis in completely obstructive colorectal cancer after stent placement.
Humans ; Neoadjuvant Therapy/methods* ; Abscess ; Retrospective Studies ; Intestinal Obstruction/etiology* ; Stents ; Colorectal Neoplasms/therapy* ; Necrosis

To evaluate the feasibility and safety of colon stenting as bridge surgery for colorectal cancer obstruction.
 Methods: A total of 30 patients (stent group), who underwent colonic stenting for colorectal obstruction at the Third Xiangya Hospital, Central South University from September 2015 to June 2017, were selected to receive the preoperative bridge surgery. Technical success rates, clinical success rates, and stent-related complications were observed. A total of 38 patients (emergency surgery group), who underwent surgical operation for colorectal obstruction, served as a control. The tumor resection rate at Stage I, ostomy rate, hospitalization time, and hospitalization cost were compared between the 2 groups.
 Results: The technical success and clinical success rates were 100.0% and 90.0% in the stent group, respectively. The stent-related complications included bleeding in 2 cases (6.7%), micro-perforation in 1 case (3.3%), stent displacement in 1 case (3.3%), and stent occlusion in 3 cases (10.0%) in the stent group. The Stage I tumor resection rate in the stent group was significantly higher than that in the emergency surgery group (90.0% vs 68.4%, P<0.01). The incidence of anastomotic leakage in the stent group was lower than that in the emergency surgery group (3.3% vs 10.5%, P<0.05); the stoma rate in the stent group was lower than that in the emergency surgery group (13.3% vs 44.7%, P<0.01). The surgical complications occurred in the stent group were significantly lower than those in the emergency surgery group (20.0% vs 47.3%, P<0.01). The average hospital stay in the stent group was lower than that in the emergency surgery group (20.0 vs 24.5 days, P<0.05). There was no significant difference in hospitalization costs between the 2 groups (P>0.05).
 Conclusion: Preoperative colonic stenting for colorectal obstruction surgery as a bridge is feasible in terms of methods, and which can significantly increase the Stage I tumor resection rate, reduce the ostomy rate, decrease surgical complications, shorten the average length of hospital stay, and reduce patient suffering.
Colorectal Neoplasms ; complications ; Humans ; Intestinal Obstruction ; etiology ; therapy ; Stents ; Treatment Outcome

Despite the success of colonoscopy screening and recent advances in cancer treatment, colorectal cancer (CRC) still remains one of the most commonly diagnosed and deadly cancers, with a significantly increased incidence in developing countries where people are adapting to Western lifestyle. Diet has an important impact on risk of CRC. Multiple epidemiological studies have suggested that excessive animal protein and fat intake, especially red meat and processed meat, could increase the risk of developing CRC while fiber could protect against colorectal tumorigenesis. Mechanisms have been investigated by animal studies. Diet could re-shape the community structure of gut microbiota and influence its function by modulating the production of metabolites. Butyrate, one of the short-chain fatty acids (SCFAs), which act as a favorable source for colonocytes, could protect colonic epithelial cells from tumorigenesis via anti-inflammatory and antineoplastic properties through cell metabolism, microbiota homeostasis, antiproliferative, immunomodulatory and genetic/epigenetic regulation ways. In contrast, protein fermentation and bile acid deconjugation, which cause damage to colonic cells through proinflammatory and proneoplastic ways, lead to increased risk of developing CRC. In conclusion, a balanced diet with an increased abundance of fiber should be adopted to reduce the risk and prevent CRC.
Animals ; Colorectal Neoplasms ; etiology ; prevention & control ; Diet ; Gastrointestinal Microbiome ; Humans

OBJECTIVES: Previous large-scale cohort studies conducted in Korea have found a positive association between diabetes mellitus (DM) and colorectal cancer (CRC) in men only, in contrast to studies of other populations that have found significant associations in both men and women. METHODS: A total of 1070 CRC cases and 2775 controls were recruited from the National Cancer Center, Korea between August 2010 and June 2013. Self-reported DM history and the duration of DM were compared between cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by binary and polytomous logistic regression models. RESULTS: DM was associated with an elevated risk of CRC in both men (OR, 1.47; 95% CI, 1.13 to 1.90) and women (OR, 1.92; 95% CI, 1.24 to 2.98). This association remained when we controlled for age, body mass index, alcohol consumption, and physical activity level. In sub-site analyses, DM was associated with distal colon cancer risk in both men (multivariate OR, 2.04; 95% CI, 1.39 to 3.00) and women (multivariate ORs, 1.99; 95% CI, 1.05 to 3.79), while DM was only associated with rectal cancer risk in women (multivariate OR, 2.05; 95% CI, 1.10 to 3.82). No significant association was found between DM and proximal colon cancer risk in either men (multivariate OR, 1.45; 95% CI, 0.88 to 2.41) or women (multivariate OR, 1.79; 95% CI, 0.78 to 4.08). CONCLUSIONS: Overall, DM was associated with an increased risk of CRC in Koreans. However, potential over-estimation of the ORs should be considered due to potential biases from the case-control design.
Adult ; Aged ; Case-Control Studies ; Cohort Studies ; Colorectal Neoplasms/*etiology ; Diabetes Mellitus, Type 2/*complications ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Odds Ratio ; Republic of Korea ; Risk Factors

BACKGROUND/AIMS: Although colonoscopy is not indicated in patients with hematochezia, many surgeons, internists, and physicians are recommending colonoscopy for these patients in Korea. The aim of this study is to evaluate the diagnostic value of colonoscopy for patients with hematochezia. METHODS: We retrospectively reviewed the data of colonoscopy between January 2010 and December 2010. A total of 321 patients among 3,038 colonoscopies (10.6%) underwent colonoscopy to evaluate the cause of hematochezia. The patients with previous colorectal surgery (2) or polypectomy (5) were excluded. We analyzed endoscopic diagnoses. Advanced neoplastic polyps were defined as adenomas with villous histology or high grade dysplasia, or adenomas more than 10 mm in diameter. RESULTS: Hemorrhoid was the most common diagnosis (217 cases, 67.6%). Polyps were detected in 93 patients (29.0%), but advanced neoplastic polyps were found in only 14 cases (4.4%). Colorectal cancers were diagnosed in 18 patients (5.6%) including 14 rectal cancers. There was no cancer located above sigmoid-descending junction. Diverticuli were detected in 41 patients (12.8%) but there was only one case of suspected diverticular bleeding. Colitis was diagnosed in 24 patients (7.5%). Other lesions included acute anal fissure, rectal tumor, stercoral ulcer, and radiation proctitis. CONCLUSIONS: The colonoscopy had little value in patients with hematochezia because the most pathologic lesions were located below sigmoid colon. The first choice of diagnosis in patients with hematochezia is sigmoidoscopy.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Colitis/complications/diagnosis ; Colonic Neoplasms/complications/diagnosis ; Colonic Polyps ; *Colonoscopy ; Colorectal Neoplasms/complications/diagnosis ; Female ; Gastrointestinal Hemorrhage/diagnosis/*etiology ; Hemorrhoids/complications/diagnosis ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Young Adult

BACKGROUND/AIMS: Esophageal squamous cell carcinoma (ESCC) and colorectal neoplasms (CRNs) share risk factors. We aimed to investigate whether the CRN risk is increased in ESCC patients. METHODS: ESCC patients who underwent a colonoscopy within 1 year of diagnosis were retrospectively analyzed. Patients were matched 1:3 by age, gender, and body mass index to asymptomatic controls. CRN was defined as the histological confirmation of adenoma or adenocarcinoma. Advanced CRN was defined as any of the following: > or =3 adenomas, high-grade dysplasia, villous features, tumor > or =1 cm, or adenocarcinoma. The risk factors for both CRN and advanced CRN were evaluated by univariate and multivariate analyses. RESULTS: Sixty ESCC patients were compared with 180 controls. The ESCC group had significantly higher numbers of CRNs (odds ratio [OR], 2.311; 95% confidence interval [CI], 1.265 to 4.220; p=0.006) and advanced CRNs (OR, 2.317; 95% CI, 1.185 to 4.530; p=0.013). Significant risk factors for both CRN and advanced CRN by multivariate analysis included ESCC (OR, 2.157, 95% CI, 1.106 to 4.070, p=0.024; and OR, 2.157, 95% CI, 1.045 to 4.454, p=0.038, respectively) and older age (OR, 1.068, 95% CI, 1.032 to 1.106, p<0.001; and OR, 1.065, 95% CI, 1.024 to 1.109, p=0.002, respectively). CONCLUSIONS: The rates of CRN and advanced CRN are significantly increased in ESCC. Colonos-copy should be considered at ESCC diagnosis.
Adenocarcinoma/diagnosis/*etiology ; Adenoma/diagnosis/*etiology ; Aged ; Carcinoma, Squamous Cell/diagnosis/*etiology ; Case-Control Studies ; Colonoscopy ; Colorectal Neoplasms/diagnosis/*etiology ; Esophageal Neoplasms/diagnosis/*etiology ; Female ; Humans ; Male ; Middle Aged ; Neoplasms, Multiple Primary/diagnosis/*etiology ; Odds Ratio ; Retrospective Studies ; Risk Factors

BACKGROUND/AIMS: Colorectal adenomas that are > or =10 mm have villous histology or high-grade dysplasia, or that are associated with > or =3 adenomas are considered high-risk for metachronous advanced neoplasia. We evaluated the cumulative incidence of metachronous advanced neoplasia according to the total number of high-risk findings detected on baseline colonoscopy. METHODS: This was a retrospective cohort study performed in 862 patients who underwent removal of colorectal adenomas between 2005 and 2009. At least one surveillance colonoscopy had been conducted at Konkuk University Medical Center, Seoul, Korea. RESULTS: The cumulative incidence of metachronous advanced neoplasia in patients with 0, 1, 2, and 3-4 high-risk findings at 1 year were 0.7%, 1.3%, 2.8%, and 8.0%; at 3 years, those were 5.9%, 11.9%, 15.5%, and 24.7%; and at 5 years, those were 8.5%, 18.7%, 26.3%, and 37.2%, respectively. In a multivariate model, the risk of metachronous advanced neoplasia was significantly higher for the multiple high-risk findings group when compared with the 0 high-risk findings group (1 high-risk (+): hazard ratio, 1.86 [95% confidence interval, 1.00-3.44]; 2 high-risk (+): 1.84 [0.88-3.84]; and 3-4 high-risk (+): 3.29 [1.54-7.01]; ptrend=0.020). CONCLUSIONS: The presence of overlapping multiple high-risk findings was associated with an increased risk of advanced neoplasia during surveillance.
Adenoma/epidemiology/*etiology/pathology ; Aged ; Colonic Polyps/complications/surgery ; *Colonoscopy ; Colorectal Neoplasms/epidemiology/*etiology/pathology ; Early Detection of Cancer/methods ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Neoplasm Grading ; Neoplasms, Second Primary/epidemiology/*etiology/pathology ; Population Surveillance/methods ; Proportional Hazards Models ; Republic of Korea/epidemiology ; Retrospective Studies ; Risk Factors ; Time Factors ; Tumor Burden