Efficacy of cecal retroflexion observed on adenoma missing of ascending colon during colonoscopy: A prospective, randomized, pilot trial.

BACKGROUND: Although colonoscopic retroflexion has been proved effective in reducing missed adenomas, there is still a lack of comprehensive and in-depth research focused on the ascending colon. We aimed to conduct a randomized controlled trial and tandem colonoscopy to investigate whether cecal retroflexion observed during colonoscopy can reduce missed adenomas in the ascending colon. METHODS: Men and women required to be between 45 and 80 years of age were screened for enrollment in the trial. Patients were randomly assigned according to a 1:1 ratio to either the trial group or control group. Patients in the trial group underwent 2 forward examination and a cecal retroflexion observed in the ascending colon, while patients in the control group underwent only 2 forward examinations in the ascending colon. The primary outcome was adenoma miss rate. The secondary outcomes contained adenoma detection rate, polyp miss rate, polyp detection rate, insertion time and withdrawal time. Differences between groups in the primary outcome and in the other categorical indicators were tested using chi-squared test and Fisher exact test. For the comparison of continuous outcomes, the Student t test was applied. RESULTS: A total of 60 subjects were eligible for the study between April to June 2020, of which 55 were randomized and eligible for analysis (26 to the control group and 29 to the trial group). The characteristics of patients were no significant differences statistically between the trial group and the control group. Similarly, the characteristics of the colonoscopy procedures included cecal insertion distance, the length of cecum and ascending colon, insertion time, withdrawal time, quality of bowel preparation, numerical rating scale for pain, polyps detected, and adenomas detected, and there were no significant differences statistically between the 2 groups (P = .864, P = .754, P = .700, P = .974, P = .585, P = .835, P = .373, P = .489). The characteristics of the polyps were also no significant differences statistically between the 2 groups. CONCLUSION: This pilot trial failed to show benefit of cecal retroflexion observed on adenoma missing of ascending colon during colonoscopy; however, further conclusions require a prospective study with a higher level of evidence. (NCT03355443).

Association of cigarette smoking with risk of colorectal cancer subtypes classified by gut microbiota.

INTRODUCTION: Both cigarette smoking and gut microbiota play important roles in colorectal carcinogenesis. We explored whether the association between smoking and colorectal cancer (CRC) risk varies by gut microbial enterotypes and how smoking-related enterotypes promote colorectal carcinogenesis. METHODS: A case-control study was conducted. Fecal microbiota was determined by 16S rDNA sequencing. The cases with CRC or adenoma were subclassified by gut microbiota enterotypes. Multivariate analyses were used to test associations between smoking and the odds of colorectal neoplasm subtypes. Mann-Whitney U tests were used to find differential genera, genes, and pathways between the subtypes. RESULTS: Included in the study were 130 CRC patients (type I: n=77; type II: n=53), 120 adenoma patients (type I: n=66; type II: n=54), and 130 healthy participants. Smoking increased the odds for type II tumors significantly (all p for trend <0.05) but not for type I tumors. The associations of smoking with increased odds of colorectal neoplasm significantly differed by gut microbiota enterotypes (p<0.05 for heterogeneity). An increase in carcinogenic bacteria (genus Escherichia shigella) and a decrease in probiotics (family Lachnospiraceae and Ruminococcaceae) in type II tumors may drive disease progression by upregulating oncogenic signaling pathways and inflammatory/oxidative stress response pathways, as well as protein phospholipase D1/2, cytochrome C, and prostaglandin-endoperoxide synthase 2 expression. CONCLUSIONS: Smoking was associated with a higher odds of type II colorectal neoplasms but not type I tumors, supporting a potential role for the gut microbiota in mediating the association between smoking and colorectal neoplasms.

Gut Microbiota Enterotypes Mediate the Effects of Dietary Patterns on Colorectal Neoplasm Risk in a Chinese Population.

Colorectal cancer (CRC) risk is influenced by dietary patterns and gut microbiota enterotypes. However, the interaction between these factors remains unclear. This study examines this relationship, hypothesizing that different diets may affect colorectal tumor risk in individuals with varied gut microbiota enterotypes. We conducted a case-control study involving 410 Han Chinese individuals, using exploratory structural equation modeling to identify two dietary patterns, and a Dirichlet multinomial mixture model to classify 250 colorectal neoplasm cases into three gut microbiota enterotypes. We assessed the association between dietary patterns and the risk of each tumor subtype using logistic regression analysis. We found that a healthy diet, rich in vegetables, fruits, milk, and yogurt, lowers CRC risk, particularly in individuals with type I (dominated by Bacteroides and Lachnoclostridium) and type II (dominated by Bacteroides and Faecalibacterium) gut microbiota enterotypes, with adjusted odds ratios (ORs) of 0.66 (95% confidence interval [CI] = 0.48-0.89) and 0.42 (95% CI = 0.29-0.62), respectively. Fruit consumption was the main contributor to this protective effect. No association was found between a healthy dietary pattern and colorectal adenoma risk or between a high-fat diet and colorectal neoplasm risk. Different CRC subtypes associated with gut microbiota enterotypes displayed unique microbial compositions and functions. Our study suggests that specific gut microbiota enterotypes can modulate the effects of diet on CRC risk, offering new perspectives on the relationship between diet, gut microbiota, and colorectal neoplasm risk.

Re-recognition of BMPR1A-related polyposis: beyond juvenile polyposis and hereditary mixed polyposis syndrome.

Background: Bone morphogenetic protein receptor type 1A (BMPR1A) is responsible for two individual Mendelian diseases: juvenile polyposis syndrome and hereditary mixed polyposis syndrome 2, which have overlapping phenotypes. This study aimed to elucidate whether these two syndromes are just two subtypes of a single syndrome rather than two isolated syndromes. Methods: We sequenced the BMPR1A gene in 186 patients with polyposis and colorectal cancer, and evaluated the clinicopathological features and phenotypes of the probands and their available relatives with BMPR1A mutations. Results: BMPR1A germline mutations were found in six probands and their three available relatives. The numbers of frameshift, nonsense, splice-site, and missense mutations were one, one, two, and two, respectively; two of the six mutations were novel. Typical juvenile polyps were found in only three patients. Two patients had colorectal cancer rather than any polyps. Conclusions: Diseases in BMPR1A germline mutation carriers vary from mixed polyposis to sole colorectal cancer, and typical juvenile polyps do not always occur in these carriers. The variety of phenotypes reflected the features of BMPR1A-mutation carriers, which should be recognized as a spectrum of one syndrome. Genetic testing may be a good approach to identifying BMPR1A-related syndromes.

Self-expanding metal stent insertion by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring in the management of acute colorectal obstruction: a 14-year experience.

BACKGROUND: Placement of a self-expanding metal stent (SEMS) in patients presenting with an acute colorectal obstruction (ACO) may obviate emergency surgery (ES), potentially effectively palliating incurable tumors, acting as a bridge to surgery (BTS) in patients with operable or potentially operable tumors and achieving effective decompression of other ACO. We present our experience with SEMS insertion by colorectal surgeons without fluoroscopic monitoring for ACO especially for acute malignant colorectal obstruction (AMCO) for nearly a 14-year period (2007-2020). AIM: To explore the safety and effectiveness of SEMS insertion in the management of ACO by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring. METHODS: We reviewed the medical records of patients retrospectively to identify all patients presenting to our unit with ACO especially with AMCO who had stenting carried out to achieve colonic decompression. All 434 procedures were performed by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring. RESULTS: The overall technique success rate and clinic success rate by SEMS insertion were 428/434 (98.6%) and 412/434 (94.9%). The overall incidence of complications by SEMS insertion was 19/434 (4.4%). The complications included clinical perforation (6/434, 1.4%); stent migration (2/434, 0.5%), 1 of which re-stent; stent detachment (fell off) (3/434, 0.7%), none of them with re-stent; stool impaction (6/434, 1.4%), 1 of which re-stent; and abdominal or anal pain (2/434, 0.5%). There was no hemorrhage in any of the 434 patients. CONCLUSIONS: SEMS insertion is a relatively safe and effective technique for colonic decompression in dealing with ACO as either a BTS or as a palliative measure. It is also a solution to other causes of ACO such as recurrent tumor, benign diseases, or extra-luminal compression. Therefore, ES was largely avoided.

Delayed diagnosis of Peutz-Jeghers syndrome due to pathological information loss or mistake in family/personal history.

OBJECTIVE: To report Peutz-Jeghers syndrome (PJS) cases with non-definitive clues in the family or personal history and finally diagnosed through pathological examination and STK11 gene mutation test. CLINICAL PRESENTATION AND INTERVENTION: PJS was suspected in 3 families with tortuous medical courses. Two of them had relatives departed due to polyposis or colon cancer without pathological results, and the other one had been diagnosed as hyperplastic polyposis before. Diagnosis of PJS was confirmed by endoscopy and repeated pathological examinations, and the STK11 mutation test finally confirmed the diagnosis at genetic level, during which 3 novel mutation were detected (536C > A, 373_374insA, 454_455insGGAGAAGCGTTTCCCAGTGTGCC). CONCLUSION: Early diagnosis of PJS is important and may be based on a family history with selective features among family members, and the pathological information is the key. The novel mutations also expand the STK11 variant spectrum.

Early screening the small bowel is key to protect Peutz-Jeghers syndrome patients from surgery: a novel mutation c.243delG in STK11 gene.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a Mendelian disease, whose causative gene is STK11, mainly characterized by gastrointestinal polyposis and increased cancer risk. Clinical observation reveals intussusception in childhood are more frequent and severe than in adults, and it is difficult to prevent this knotty complication. CASE PRESENTATION: A boy without a positive family history grew oral MP after birth and developed abdominal pain and bloody stood at 7 years old. Endoscopy revealed multiple polyps within the colon and the ileum, and endoscopic polypectomy and regular surveillance protected him from severe complications and open surgeries. A heterozygous deletion in STK11, c.243delG, was detected in the proband but not in his parents. This mutation has not been documented in databases. CONCLUSIONS: We suspect a child of PJS may need a more thorough endoscopic examination including enteroscopy or capsule endoscopy to take care of small bowel when PJS related symptoms comes up.

STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients.

BACKGROUND: The combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities. AIMS: To test the efficacy of the combination in Chinese patients with PJS. METHODS: PJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically. RESULTS: We identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors. CONCLUSION: The strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.

Adenoma miss rate determined by very shortly repeated colonoscopy: Retrospective analysis of data from a single tertiary medical center in China.

Adenoma miss rate (AMR) has been calculated in several tandem colonoscopy studies, but it costs overmuch to carry out a clinical trial.We aimed to put forward AMR by taking advantage of retrospective data, and to judge the comparability between AMRs from prospective and retrospective data.Data of the patients accepting repeated colonoscopies during January to September 2016 was retrospectively collected and analyzed. Information was recorded, including bowel preparation quality of the first colonoscopy, size, location, histology and whether missed within the first colonoscopy of each single adenoma. AMR was compared by different risk factors through χ test and multivariable logistic regression.Around 267 adenomas were detected during 309 pairs of repeated colonoscopies, of which 66 were missed during the first colonoscopies. AMRs of the lesions small in size, nonadvanced in histology, in poor bowel preparation context and located in the proximal colon, were significantly higher than the opposite ones, and old age and male were related to adenoma missing (P < .05). In multivariable logistic regression analysis, adenoma-related factors (diminutive in size, poor bowel preparation and located in ascending colon, transverse colon or sigmoid colon), and patient-related factors (older than 60 years, male and poor bowel preparation) were found to be independently associated with missing adenomas (P < .05).AMR of retrospective data is comparable to that of tandem studies. Several risk factors influence AMR dramatically, which should be paid attention to.

The altered activity of P53 signaling pathway by STK11 gene mutations and its cancer phenotype in Peutz-Jeghers syndrome.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is caused by mutations in serine/threonine kinase 11 (STK11) gene. The increased cancer risk has been connected to P53 pathway. METHODS: PJS probands with STK11 mutation were included in the function analysis. P53 activity elevated by STK11 mutants was investigated using dual-luciferase reporter assay in vitro after constructing expression vectors of STK11 wild type and mutants generated by site-directed substitution. The association between the P53 activity and clinicopathological factors was analysis, especially the cancer history. RESULTS: Thirteen probands with STK11 mutations were involved, and within the mutations, c.G924A was novel. P53 activity elevation caused by 6 truncating mutations were significantly lower than that of STK11 wild type (P < 0.05). Family history of cancer was observed in 5 families. Within them, P53 activity was reduced and cancer occurred before 40 in 2 families, while it was not significantly changed and cancers happened after 45 in the other 3 families. CONCLUSIONS: The affected P53 activity caused by STK11 mutations in PJS patients is significantly associated with protein truncation, while cancer risk in PJS can be elevated through pathways rather than P53 pathway. P53 activity test is probably a useful supporting method to predict cancer risk in PJS, which could be helpful in clinical practice.

Close and regular surveillance is key to prevent severe complications for Peutz-Jeghers syndrome patients without gastrointestinal polyps: case report of a novel STK11 mutation (c.471_472delCT) in a Chinese girl.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a Mendelian disease characterized by gastrointestinal hamartomas, mucocutaneous pigmentation (MP), and increased cancer risk. Serine/threonine kinase 11 (STK11) is the only validated causative gene in PJS. Clinical observation reveals MP and intussusception in childhood are more frequent and severe than in adults. CASE PRESENTATION: We report here a girl without a positive family history, who grew oral and fingertip MP at her age of 2 and got abdomen dull pain from 7 years old. Endoscopy revealed no obvious polyps in the stomach or the colon until 10 years old, when she received enteroscopy. Tens of polyps were resected during enteroscopy, and pathological examination confirmed them hamartomas. A heterozygous deletion in STK11, c.471_472delCT, was detected in the proband but not in her parents, which is not recorded in databases. CONCLUSION: The mutation we reported here is a novel one and a de-novo one, so our results enlarge the spectrum of STK11. We speculate close and regular endoscopy especially enteroscopy is necessary for complication prevention when the former endoscopy discovers no polyps temporarily in a child of suspect PJS.

Long-Term Oncological Outcomes of Endoscopic Stenting as a Bridge to Surgery Versus Emergency Surgery for Malignant Colorectal Obstruction: A Comparative Study.

AIM: With consideration of the theoretical link between the stent insertion and the increased risk of tumor cells spillaged, which may lead to distant metastases, there is a concern about long-term clinical outcomes after the usage of self-expanding metallic stents (SEMS) as a "bridge to surgery" in the malignant colorectal obstruction (MCO) treatment. This cohort study aimed to compare the long-term oncological outcomes of SEMS as a bridge to surgery (SEMS group) with those of emergency surgery (ES group) for MCO. METHODS: Twenty-seven patients who underwent semielective curative resection after endoscopic SEMS insertion were included from October 2007 to December 2012 in the SEMS group were compared with 33 patients who underwent emergency curative surgery for MCO during the same period in the ES group. The clinical pathologic characteristics and the overall survival (OS) rate were compared between the two groups. RESULTS: There were no significant differences in demographics, tumor stage, location, and histology between the SEMS and ES groups. The median OS times were 37 months for the SEMS group and 23 months for the ES group. The proportions of patients who received postoperative adjuvant chemotherapy were comparable (SEMS group versus ES group, 70.4% versus 45.5%; P = .138). There were no significant differences in terms of the long-term oncological outcome between two groups in the 3-year OS rate (55.6% versus 39.4%; P = .2119) and the 5-year OS rate (48.1% versus 36.4%; P = .3570). CONCLUSIONS: Long-term oncological outcomes of the SEMS group were comparable to those of the ES group.

Endoscopic submucosal dissection versus transanal local excision for rectal carcinoid: a comparative study.

AIM: The aim of this study is to compare the short-term clinical outcomes between endoscopic submucosal dissection and transanal local excision for rectal carcinoid tumors. METHODS: Between 2007 and 2012, 31 patients with rectal carcinoid underwent endoscopic submucosal dissection at our hospital. They were compared with a matched cohort of 23 patients who underwent transanal local excision for rectal carcinoid between 2007 and 2012. Short-term clinical outcomes including surgical parameters, postoperative recovery, and oncologic outcomes were compared between the two groups. RESULTS: The mean size of tumors was significantly bigger in the transanal local excision group (0.8 ± 0.2 versus 1.1 ± 0.5 cm; P = 0.018). En bloc resection was achieved for 30 patients (97 %) in the endoscopic submucosal dissection group and all the patients in the transanal local excision group. The operation time was longer in the transanal local excision than that in the endoscopic submucosal dissection group (40.0 ± 22.7 min versus 12.2 ± 5.3 min; P < 0.001). Complications in the transanal local excision group were five cases of acute retention of urine. There was no local recurrence or distant metastasis in either group during the follow-up period. CONCLUSION: For the treatment of rectal carcinoid tumors with diameter <1 cm, endoscopic submucosal dissection has better short-term clinical outcomes than transanal local excision in terms of faster recovery and possibly a lower morbidity rate. Transanal local excision may be the first therapeutic choice of scar-embedded rectal carcinoid tumors.

The Sex Difference in Basic Surgical Skills Learning: A Comparative Study.

BACKGROUND: Very little is known of sex-related differences among medical students in the acquisition of basic surgical skills at an undergraduate level. The aim of this study was to investigate the sex differences in basic surgical skills learning and the possible explanations for sex disparities within basic surgical skills education. METHODS: A didactic description of 10 surgical skills was performed, including knot tying, basic suture I, basic suture II, sterile technique, preoperative preparation, phlebotomy, debridement, laparotomy, cecectomy, and small bowel resection with hand-sewn anastomosis. The students were rated on a 100-point scale for each basic surgical skill. Later during the same semester all the students took the final theoretical examination. RESULTS: A total of 342 (male = 317 and female = 25) medical students participated in a single skills laboratory as part of their third-year medical student clerkship. The mean scores for each of the 10 surgical skills were higher in female group. The difference in sterile technique, preoperative preparation, cecectomy, and small bowel resection with hand-sewn anastomosis reached the significant level. Compared with male medical students, the mean theory examination score was significantly higher in female medical students. Approximately 76% of the (19 of 25) female students expressed their interest in pursuing a surgical career, whereas only 65.5% (207 of 317) male students wanted to be surgical professionals (p = 0.381). CONCLUSIONS: Female medical students completed basic surgical skills training more efficiently and passed the theoretical examination with significantly higher scores than male medical students. In the future, studies should be done in other classes in our institution and perhaps other schools to see if these findings are reliable or valid or just a reflection of this 1 sample.

A long-term follow-up study on the prognosis of endoscopic submucosal dissection for colorectal laterally spreading tumors.

BACKGROUND AND AIMS: Colorectal laterally spreading tumors (LSTs) are divided into homogeneous (LST-G-H), nodular mixed (LST-G-M), flat elevated (LST-NG-F), and pseudodepressed (LST-NG-PD) subtypes. We hypothesized that based on the rates of advanced histology, the recurrence rates of the LST-NG-PD and LST-G-M groups may be higher than those of the other subgroups. METHODS: Endoscopic submucosal dissection (ESD) was performed in 156 patients with a total of 177 LSTs. The clinicopathological features and long-term prognosis of ESD according to specific subtype were investigated. RESULTS: LSTs were most commonly found in the rectum, and the highest percentage of rectal lesions was observed in the LST-G-M group (71.1% vs overall 55.4%, P = .032). The LST-G-M lesions were larger (60 ± 22 mm vs 40 ± 33 mm, P = .034) than the LST-G-H lesions. The LST-G-M group also demonstrated more high-grade intraepithelial neoplasias (32.2% vs 10.8%, P = .003) and submucosal carcinomas (13.6% vs 1.5%, P = .010) compared with the LST-G-H group. The LST-NG-PD group exhibited the highest incidence of submucosally invasive cancer (16.7%). The overall perforation rate was 2.3%. The perforation rate in the LST-NG group was higher than that in the LST-G group (5.7% vs 0.8%, P = .047). All recurrences (7.7%) were found by colonoscopy without any detection of cancers, and no difference was found among the subtypes. CONCLUSIONS: No significant differences were observed among subgroups with 44.4 ± 16.3 months of follow-up. Considering that all recurrences were discovered by colonoscopy and most could be cured by repeated ESD, the LSTs of all subgroups require more intensive follow-up compared with smaller adenomatous lesions.