Proportion of flat- and depressed-type and laterally spreading tumor among advanced colorectal neoplasia

Sex Difference of Colon Adenoma Pathway and Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most common causes of cancer morbidity in both sexes but shows sex differences. First, sex-specific differences in tumor recurrence and survival rates have been reported. For example, the development of CRC is found about 1.5 times higher and 4-8 years earlier in males compared to females, suggesting the protective role of estrogen in the disease. Furthermore, female patients have a higher risk of developing right-sided (proximal) colon cancer than male patients, which is known to have more aggressive clinical character compared to left-sided (distal) colon cancer. That is, left and right CRCs show differences in carcinogenic mechanism, that the chromosomal instability pathway is more common in left colon cancer while the microsatellite instability and serrated pathways are more common in right colon cancer. It is thought that there are sex-based differences on the background of carcinogenesis of CRC. Sex differences of CRC have two aspects, sexual dimorphism (biological differences in hormones and genes) and gender differences (non-biological differences in societal attitudes and behavior). Recently, sex difference of colon adenoma pathway and sexual dimorphism in the biology of gene and protein expression, and in endocrine cellular signaling in the CRC carcinogenesis have been accumulated. In addition, behavioral patterns can lead to differences in exposure to risk factors such as drinking or smoking, diet and physical activity. Therefore, understanding sex/gender-related biological and sociocultural differences in CRC risk will help in providing strategies for screening, treatment and prevention protocols to reduce the mortality and improve the quality of life. In this review, sex/gender differences in colon adenoma pathway and various aspects such as clinicopathological, biological, molecular, and socio-cultural aspects of CRC were described.

Thirty-two-year trends of cancer incidence by sex and cancer site in the Veneto Region from 1987 to 2019

Background

This observational study considers the sex-specific incidence of the most incident cancers as recorded in the population-based Veneto Regional Cancer Registry over a period of more than 30 years (1987-2019).

Methods

The Veneto Regional Cancer Registry collected data for the time interval 1987-2019. Significant changes in incidence trends calculated on age-standardized incidence rates (Annual Percent Change-APC) were identified by join point regression analysis.

Results

Overall, the incidence trend for all cancers decreased in males and remained stable in females. In nine cancer sites, the incidence trends showed consistent differences by sex (oral cavity, esophagus, colon rectum and anus, liver, larynx, lung, cutaneous malignant melanoma, bladder, and thyroid gland). Other malignancies did not show significant sex-related differences (stomach, pancreas, biliary tract, kidney/urinary tract, central nervous system, multiple myeloma, non-Hodgkin lymphoma, and leukemia).

Conclusion

In the period 1987-2019, this study revealed sex-related differences in cancer incidence trends. Over time, cancer incidence remained higher in males, with a decreasing epidemiological impact, plausibly resulting from prevention campaigns against environmental cancer risk factors, as tobacco and alcohol. Conversely, a significant decrease was not observed in the incidence trend in females. These findings contribute essential insights for profiling the epidemiological map of cancer in a large Italian population, allowing comparison with other European cancer epidemiology studies and providing updated data supporting sex-related primary and secondary cancer prevention strategies.

Serum Cytokine and miRNA Levels Are Differently Expressed in Right- and Left-Sided Colon Cancer

The tumor location in colorectal cancer (right- or left-sided colon cancer) is a key factor in determining disease progression. Right- and left-sided colon tumors are different in their clinical and molecular characteristics. Dysregulation of serum levels of proinflammatory cytokines, such as Transforming Growth Factor β (TGF-β) and Tumor Necrosis Factor-α (TNF-α), and Peroxisome Proliferator Activated Receptor-γ (PPAR-γ), known to be a growth-limiting and differentiation-promoting factor, as well as changes in miRNAs expression, are the major signaling pathways involved in the pathogenesis of this neoplasia. In the serum from 60 colorectal cancer (CRC) patients, we compared the differences in the expression of the levels of TGF-β, TNF-α, and PPAR-γ and in the expression of the main human miRNAs between right and left CRC. A significant over-expression in the TGF-β and TNF-α levels was observed in the serum from right-sided colon cancer patients. For the PPAR-γ, the patients with CRC located on the right-side showed lower levels than those detected in the serum from left-sided CRC subjects. Furthermore, significant differences also existed in the expression of specific circulating miRNAs between right- and left-sided CRC. In particular, the right upregulated miRNAs were all involved in the cell growth and proliferation related pathways. These findings confirm that the analysis of circulating levels of TGF-β, TNF-α, and PPAR-γ, as well as the study of the specific miRNAs in the serum, are able to identify specific characteristics of CRC patients, useful for choosing a personalized treatment protocol.

Sex-specific differences in colorectal cancer: A multicenter retrospective cohort study

BACKGROUND

Due to sex-specific differences in the incidence and clinical and histopathological characteristics of colorectal cancer (CRC), understanding the impact of sex on CRC may suggest sex-targeted strategies for screening, treatment, and prevention, leading to improved prognosis of CRC. However, there have been few studies investigating the sex-specific differences in CRC in the Republic of Korea. We aimed to assess sex differences in CRC in the Republic of Korea.

METHODS

This was a retrospective, multicenter, cohort study of patients diagnosed with CRC between January 2012 and December 2013 at nine hospitals. Patients who had an uncertain CRC stage, were diagnosed with other cancers within 5 years, had carcinoma in situ, non-epithelial cancer, or primary cancer other than CRC, were excluded. Factors associated with overall survival or progression-free survival were investigated using Cox regression analysis. Cumulative probability of metachronous lesions was compared using the Kaplan-Meier estimator survival analysis and we compared the survival curves of each group using a log-rank test. Outcomes were compared using the chi-square, Fisher's exact, or Student's t-test, as appropriate.

RESULTS

Three thousand one hundred and forteen patients (1999 men, 1315 women) were included. There was no significant difference in the age at onset between men and women. The proportion of patients diagnosed through regular health check-ups, and asymptomatic at time of diagnosis, was higher in men (48.9% men vs. 42.0% women, p < .001). Rectal cancers were more common in men (38.8% men vs. 31.8% women, p < .001). Right colon cancers were more common in women (31.4% women vs. 22.7% men, p < .001). KRAS mutations were found in 109/317 (34.4%) women and 112/480 (23.3%) men. Overall CRC survival and progression-free survival were similar in both sexes.

CONCLUSION

Sex differences in CRC may be due to the biological and social-behavioral differences between the sexes. They should be considered during screening, diagnosis, and treatment of CRC for better outcomes.

Comparison of precutting endoscopic mucosal resection and endoscopic submucosal dissection for large (20-30 mm) flat colorectal lesions

BACKGROUND AND AIM

The complete and safe removal of large (≥ 20 mm) colorectal lesions is an area of concern. Endoscopic submucosal dissection (ESD) effectively removes these lesions compared with endoscopic mucosal resection (EMR). However, ESD requires advanced techniques, longer procedure time, and high cost. Precutting EMR (EMR-P) is a modified EMR method that overcomes the limitations of EMR. This study aimed to compare the efficacy and safety of EMR-P and ESD in large (20-30 mm) flat colorectal lesions.

METHODS

This was a retrospective analysis of cases in which 20- to 30-mm flat colorectal lesions were resected at Seoul St. Mary's Hospital from January 2014 to December 2019. Propensity score matching was performed to control for possible confounders.

RESULTS

Two hundred and ninety-nine patients were included in this study. After matching, 90 patients were assigned to each group. There were no significant difference in complete resection rates (92.2% vs 92.2%, P = 1.000), en bloc resection rates (95.6% vs 97.8%, P = 0.682), and mean size of lesions (22.9 ± 3.1 mm vs 23.0 ± 3.1 mm, P = 0.867) between EMR-P and ESD. Procedure time was significantly shorter with EMR-P (11.0 ± 6.5 min vs 37.0 ± 19.3 min, P < 0.001). The adverse events rate was not significantly different between both groups. No local recurrence occurred in both groups.

CONCLUSIONS

Precutting EMR was not significantly different to ESD in terms of complete resection rate and en bloc resection rate for 20- to 30-mm flat colorectal lesions without fibrosis. Furthermore, EMR-P has shorter procedure time than ESD. EMR-P could be considered one of standard treatments for large flat colorectal lesions.

Robust automated prediction of the revised Vienna Classification in colonoscopy using deep learning: development and initial external validation

BACKGROUND

Improved optical diagnostic technology is needed that can be used by also outside expert centers. Hence, we developed an artificial intelligence (AI) system that automatically and robustly predicts the pathological diagnosis based on the revised Vienna Classification using standard colonoscopy images.

METHODS

We prepared deep learning algorithms and colonoscopy images containing pathologically proven lesions (56,872 images, 6775 lesions). Four classifications were adopted: revised Vienna Classification category 1, 3, and 4/5 and normal images. The best algorithm-ResNet152-in the independent internal validation (14,048 images, 1718 lesions) was used for external validation (255 images, 128 lesions) based on neoplastic and non-neoplastic classification. Diagnostic performance of endoscopists was compared using a computer-assisted interpreting test.

RESULTS

In the internal validation, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for adenoma (category 3) of 84.6% (95% CI 83.5-85.6%), 99.7% (99.5-99.8%), 90.8% (89.9-91.7%), 89.2% (88.5-99.0%), and 89.8% (89.3-90.4%), respectively. In the external validation, ResNet152's sensitivity, specificity, PPV, NPV, and accuracy for neoplastic lesions were 88.3% (82.6-94.1%), 90.3% (83.0-97.7%), 94.6% (90.5-98.8%), 80.0% (70.6-89.4%), and 89.0% (84.5-93.6%), respectively. This diagnostic performance was superior to that of expert endoscopists. Area under the receiver-operating characteristic curve was 0.903 (0.860-0.946).

CONCLUSIONS

The developed AI system can help non-expert endoscopists make differential diagnoses of colorectal neoplasia on par with expert endoscopists during colonoscopy. (229/250 words).

Low potency of fecal immunological surveillance testing soon after negative colonoscopy or resection of low-risk adenoma in average-risk patients

BACKGROUND

Postcolonoscopy surveillance colonoscopy based on positive fecal occult blood testing (FOBT) is often performed, although its long-term efficacy has not been established. The aim of this study was to clarify the low potency of FOBT surveillance at short intervals after colonoscopy.

METHODS

Colonoscopy was performed in 1308 average-risk patients, based on positive results of immunological FOBT [fecal immunological test (FIT)]. Patients were stratified according to the length of time since their last colonoscopy and their colonoscopy results [no adenoma or 1-2 small (<10 mm) adenomas]. Tumor detection rates were determined.

RESULTS

The baseline patients characteristics did not differ between the groups. The advanced lesion detection rate (ALDR) among the patients who had never undergone a colonoscopy was 21.9% [95% confidence interval (CI), 19.1-25.0%]. Among the patients who had no adenoma detected in the previous colonoscopy within the past 5 years, the past 5-10 years and over 10 years, the ALDRs were 2.5% (95% CI, 1.0-5.5%), 4.1% (95% CI, 1.5-9.4%) and 9.3% (95% CI, 3.1-22.2%), respectively. Among the patients who had 1-2 small adenomas, the ALDRs were 7.4% (95% CI, 3.4-14.8%), 12.1% (95% CI, 4.2-27.9%) and 27.8% (95% CI, 12.2-51.2%), respectively. Invasive cancer was not observed in any patients within 5 years since the prior colonoscopy.

CONCLUSION

In average-risk patients whose prior colonoscopy detected no adenomas or low-risk adenomas, postcolonoscopy surveillance by FIT has a low positive predictive value within a 5-year interval.

Second-generation narrow-band imaging to detect colorectal adenomas: A prospective study including community hospitals

BACKGROUND AND AIM

It is unclear whether second-generation narrow-band imaging (NBI) improves colorectal adenoma detection in clinical practice. We aimed to evaluate the ability of NBI to detect adenomas in academic and community hospitals.

METHODS

This observational, multicenter study was conducted in four academic and four community hospitals between July 2018 and April 2019. We enrolled patients aged ≥ 20 years who underwent colonoscopy for screening, polyp surveillance, or diagnostic workup. The primary endpoint was the adenoma detection rate (ADR) between NBI (NBI group) and white-light imaging colonoscopies (WLI group) after propensity score (PS) matching.

RESULTS

Of 1831 patients analyzed before PS matching, the NBI and WLI groups included 742 and 1089 patients, respectively. After PS matching, 711 pairs from both groups were analyzed. ADR and the mean number of adenomas per patient did not differ significantly between the NBI and WLI groups (43.5% vs 44.4%, P = 0.71; 0.90 ± 1.38 vs 0.91 ± 1.40, P = 0.95, respectively). Academic hospitals showed higher ADR in the NBI group (60.5% vs 53.8%), whereas community hospitals showed higher ADR in the WLI group (35.8% vs 40.5%). In the NBI group, ADR was significantly higher among NBI-screening-experienced endoscopists than among NBI-screening-inexperienced endoscopists (63.2% vs 39.2%, P < 0.001). The mean number of flat and depressed lesions detected per patient was significantly higher with NBI than with WLI (0.62 ± 1.34 vs 0.44 ± 1.01, P = 0.035).

CONCLUSIONS

Second-generation NBI could not surpass WLI in terms of ADR based on patient recruitment from both academic and community hospitals but improved the detection of easily overlooked flat and depressed lesions.

Risk of Covert Submucosal Cancer in Patients With Granular Mixed Laterally Spreading Tumors

BACKGROUND AND AIMS

Granular mixed laterally spreading tumors (GM-LSTs) have an intermediate level of risk for submucosal invasive cancer (SMICs) without clear signs of invasion (covert); the optimal resection method is uncertain. We aimed to determine the risk of covert SMIC in GM-LSTs based on clinical and endoscopic factors.

METHODS

We collected data from 693 patients (50.6% male; median age, 69 years) with colorectal GM-LSTs, without signs of invasion, who underwent endoscopic resection (74.2%) or endoscopic submucosal dissection (25.2%) at 7 centers in Italy from 2016 through 2019. We performed multivariate and univariate analyses to identify demographic and endoscopic factors associated with risk of SMIC. We developed a multivariate model to calculate the number needed to treat (NNT) to detect 1 SMIC.

RESULTS

Based on pathology analysis, 66 patients (9.5%) had covert SMIC. In multivariate analyses, increased risk of covert SMIC were independently associated with increasing lesion size (odds ratio per mm increase, 1.02, 95% CI, 1.01-1.03; P = .003) and rectal location (odds ratio, 3.08; 95% CI, 1.62-5.83; P = .004). A logistic regression model based on lesion size (with a cutoff of 40 mm) and rectal location identified patients with covert SMIC with 47.0% sensitivity, 82.6% specificity, and an area under the curve of 0.69. The NNT to identify 1 patient with a nonrectal SMIC smaller than 4 cm was 20; the NNT to identify 1 patient with a rectal SMIC of 4 cm or more was 5.

CONCLUSIONS

In an analysis of data from 693 patients, we found the risk of covert SMIC in patients with GM-LSTs to be approximately 10%. GM-LSTs of 4 cm or more and a rectal location are high risk and should be treated by en-bloc resection. ClinicalTrials.gov, Number: NCT03836131.

Sex difference in bowel preparation quality and colonoscopy time

BACKGROUND/AIMS

The length of colon is known to be longer in females than in males. In addition, the morphology of colon cancer is different between males and females. The aim of this study was to investigate sex differences in Boston bowel preparation score (BBPS) and colonoscopy insertion time.

METHODS

This study retrospectively analyzed medical records and colonoscopy readings of subjects who underwent colonoscopy at Seoul National University Bundang Hospital from March 2015 to April 2018. BPPS was used to evaluate the degree of colon cleanness before colonoscopy. Statistical analysis was performed to compare demographic, clinical, and outcome variables between two groups.

RESULTS

The study group consisted of a total of 12,561 patients (6,148 females and 6,413 males). Mean age was 57.8 ± 13.5 years for females and 57.5 ± 13.8 years for males (p = 0.695). Females showed better bowel preparation than males (mean total score: 7.4 ± 1.8 vs. 7.2 ± 1.9, p = 0.001; total score ≥ 6: 5,340 [86.9%] vs. 5,437 [84.8%], p = 0.001; BBPS ≥ 2 for all segments: 5,048 [82.1%] vs. 5,097 [79.5%], p < 0.001). However, cecal intubation time (8.3 ± 6.2 minutes vs. 6.2 ± 6.1 minutes, p < 0.001) and withdrawal time (7.9 ± 3.5 minutes vs. 7.4 ± 3.1 minutes, p < 0.001) were longer in males.

CONCLUSION

There were sex differences in BBPS, cecal intubation time, and withdrawal time for subjects undergoing colonoscopy.

Sexual Dimorphism in Colon Cancer

A higher incidence of colorectal cancer (CRC) is found in males compared to females. Young women (18-44 years) with CRC have a better survival outcome compared to men of the same age or compared to older women (over 50 years), indicating a global incidence of sexual dimorphism in CRC rates and survival. This suggests a protective role for the sex steroid hormone estrogen in CRC development. Key proliferative pathways in CRC tumorigenesis exhibit sexual dimorphism, which confer better survival in females through estrogen regulated genes and cell signaling. Estrogen regulates the activity of a class of Kv channels (KCNQ1:KCNE3), which control fundamental ion transport functions of the colon and epithelial mesenchymal transition through bi-directional interactions with the Wnt/β-catenin signalling pathway. Estrogen also modulates CRC proliferative responses in hypoxia via the novel membrane estrogen receptor GPER and HIF1A and VEGF signaling. Here we critically review recent clinical and molecular insights into sexual dimorphism of CRC biology modulated by the tumor microenvironment, estrogen, Wnt/β-catenin signalling, ion channels, and X-linked genes.

The Outcome of Unscreened Population in Colorectal Cancer: The Impact of Sex and Other Determinants on Cancer Stage

BACKGROUND

In Saudi Arabia, there is no population-based colorectal cancer (CRC) screening, and more than two-thirds of patients are diagnosed with a late stage. We assessed the association between sex and distant metastasis CRC and hypothesize that females, younger age, non-married, and patients with colon cancer would present with metastatic tumors.

PATIENTS AND METHODS

The retrospective cohort study used data from the Ministry of National Guard Cancer Registry. Logistic regression was used to assess the association between sex and metastatic CRC adjusting for patient covariates. In a sensitivity analysis, the association between sex and late-stage CRC was evaluated.

RESULTS

A total of 1016 CRC patients met the eligibility criteria, with 37.59% of females and 30.26% of males diagnosed with metastatic CRC. After adjusting for marital status, grade, and morphology, females were 20% more likely than males to present with a metastatic tumor 1.20 (95% CI, 1.04-1.38).

CONCLUSION

Although the entire Saudi population would benefit from CRC screening, women may benefit the most from targeted screening.

Treatment policy for colonic laterally spreading tumors based on each clinicopathologic feature of 4 subtypes: actual status of pseudo-depressed type

BACKGROUND AND AIMS

Laterally spreading tumors (LSTs) are originally classified into 4 subtypes. Pseudo-depressed nongranular types (LSTs-NG-PD) are gaining attention because of their high malignancy potential. Previous studies discussed the classification of nongranular (LST-NG) and granular types (LST-G); however, the actual condition or indication for endoscopic treatment of LSTs-NG-PD remains unclear. We aimed to compare the submucosal invasion pattern of LSTs-NG-PD with the other 3 subtypes.

METHODS

A total of 22,987 colonic neoplasms including 2822 LSTs were resected endoscopically or surgically at Showa University Northern Yokohama Hospital. In these LSTs, 322 (11.4%) were submucosal invasive carcinomas. We retrospectively evaluated the clinicopathologic features of LSTs divided into 4 subtypes. In 267 LSTs resected en bloc, their submucosal invasion site was further evaluated.

RESULTS

The frequency of LSTs in all colonic neoplasms was significantly higher in women (14.9%) than in men (11.0%). Rates of submucosal invasive carcinoma were .8% in the granular homogenous type (LSTs-G-H), 15.2% in the granular nodular mixed type (LSTs-G-M), 8.0% in the nongranular flat elevated type (LSTs-NG-F), and 42.5% in LSTs-NG-PD. Tumor size was associated with submucosal invasion rate in LSTs-NG-F and LSTs-NG-PD (P < .001). The multifocal invasion rate of LSTs-NG-PD (46.9%) was significantly higher than that of LSTs-G-M (7.9%) or LSTs-NG-F (11.8%). In LSTs-NG-PD, the invasion was significantly deeper (≥1000 μm) if observed in 1 site.

CONCLUSIONS

For LSTs-G-M and LSTs-NG-F that may have invaded the submucosa, en bloc resection could be considered. Considering that LSTs-NG-PD had a higher submucosal invasion rate, more multifocal invasive nature, and deeper invasion tendency, regardless if invasion was only observed in 1 site, than LSTs-NG-F, we should endoscopically distinguish LSTs-NG-PD from LSTs-NG-F and strictly adopt en bloc resection by endoscopic submucosal dissection or surgery for LSTs-NG-PD. (Clinical trial registration number: UMIN 000020261.).

Global Prevalence of Colorectal Neoplasia: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Most colorectal cancers (CRC) arise from colorectal adenomas, yet there is not enough information on global prevalence to inform health care policy. We examined the prevalence of any type of adenomas, advanced adenomas (AADs), and CRC according to age, sex, ethnicity, geographic regions, and anatomic location (proximal vs distal).

METHODS

MEDLINE and Embase were searched from their inception through May 1, 2018, to identify population-based, observational studies that reported the prevalence of colorectal neoplasia. Studies on participants 15 years or older, with a sample size of 500 persons or more, were included. Metaprop (College Station, TX) was used to model within-study variability by binomial distribution and Freeman-Tukey Double Arcsine Transformation to stabilize the variances. The prevalence figures were presented by proportions and their 95% CIs using random-effects models.

RESULTS

Our meta-analysis included 70 studies involving 637,414 individuals. The overall prevalence rates of adenoma (23.9%; 95% CI, 22.2%-25.8%), AAD (4.6%; 95% CI, 3.8%-5.5%), and CRC (0.4%, 95% CI, 0.3%-0.5%) were calculated. Subgroup analysis indicated that prevalence values (adenomas, AADs, and CRCs) were higher among men (29.7%, 6.5%, and 0.8%, respectively) than women (19.3%, 3.8% and 0.4%, respectively), among older adults (25.9%, 5.2%, and 0.6%, respectively) than younger adults (14.6%, 1.6%, and 0.1%, respectively), among Caucasians (23.7%, 6.6%, and 0.5%, respectively) than other ethnicities, in European countries (25.9%, 8.4%, and 0.8%, respectively) than other countries, and among patients with proximal (25.9%, 5.3%, and 0.1%, respectively) vs distal neoplasia.

CONCLUSIONS

In a systematic review and meta-analysis, we found a high prevalence of colorectal neoplasia among some populations. This indicates a need to expand CRC screening programs for these groups. The pooled prevalence estimates can be used as quality indicators for established CRC screening programs.

Gender- and Race-Based Differences in Barriers and Facilitators to Early Detection of Colon Cancer

Background: Early detection of colon cancer is essential to successful treatment and survival, yet most patients are diagnosed only after onset of symptoms. Previous studies suggest differences in colon cancer screening and presentation by gender and race, but reasons for this are not understood. The purpose of this study was to identify barriers and facilitators to early detection of colon cancer and to compare by gender and race. Materials and Methods: In the Colon Cancer Patterns of Care in Chicago study, non-Hispanic Black and White (NHB, NHW) patients aged 30-79 newly diagnosed with colon cancer between 2010 and 2014 (n = 249) underwent in-depth semistructured interviews regarding the pathway to colon cancer diagnosis. Mixed qualitative and quantitative methods were used to analyze patient narratives and to compare response patterns by gender and race within prespecified domains: health care access factors, provider-related factors, patient-related factors, and diagnostic workup factors. Results: Women reported more barriers than facilitators to early detection than men (barrier: facilitator ratio of 0.60 vs. 0.48). Thematic differences were seen, with women reporting more barriers related to health care access, scheduling of follow-ups, symptom recognition, and inappropriate or inconclusive diagnostic tests. Fewer women than men reported facilitators related to provider factors such as ease of scheduling follow-ups and receiving referrals for screening or a specialist. NHBs and NHWs reported similar ratios of barriers to facilitators (0.55 vs. 0.53), but more NHBs than NHWs reported barriers related to health care access, scheduling follow-ups, and clinical delays, and fewer NHBs reported facilitators related to health care accessibility (existing relationship with provider, ease of scheduling follow-ups). Conclusions: In this diverse population of patients recently diagnosed with colon cancer, we identified substantive gender- and race-based differences in the types and burden of barriers and facilitators to early detection experienced in the path to diagnosis. These differences should be explored further as they may contribute to disparities in the diagnosis and prognosis of colon cancer.

Risk factors associated with clinical outcomes of endoscopic mucosal resection for colorectal laterally spreading tumors: A Honam Association for the Study of Intestinal Diseases (HASID) multicenter study

BACKGROUND/AIMS

Colorectal laterally spreading tumors (LSTs) are large and superficial neoplasms. Most are adenomatous lesions. Endoscopic mucosal resection (EMR) is a standard technique of removing precursor colorectal lesions. The aim of the present study was to assess the factors associated with the clinical outcomes of EMR for LSTs.

MATERIALS AND METHODS

A total of 275 patients with LSTs who underwent EMR were enrolled in the study. The clinical outcomes of the patients were analyzed by retrospectively reviewing their medical records.

RESULTS

The en bloc resection and R0 resection rates were 86.9% and 80.4%, respectively. The bleeding and perforation rates were 7.6% and 0.4%, respectively. The frequency of high-grade dysplasia and adenocarcinoma histology was significantly higher, and the procedure time was significantly longer in LSTs >20 mm than in those ≤20 mm. The R0 resection rate was significantly higher in LSTs ≤20 mm than in those >20 mm. The frequency of piecemeal resection was significantly higher in LSTs with an adenomatous and cancerous pit pattern than in those with a non-neoplastic pit pattern. The frequency of piecemeal resection was significantly higher in LSTs with adenocarcinoma than in those with low-grade dysplasia. Multivariate analysis revealed that adenomatous pit pattern, high-grade dysplasia, or adenocarcinoma was a significant independent risk factor of LSTs for piecemeal resection after EMR.

CONCLUSION

EMR is useful for treating ≤20 mm LSTs with regard to curative resection and procedure time. LSTs with an adenomatous pit pattern, high-grade dysplasia, or adenocarcinoma are significant independent risk factors for piecemeal resection after EMR.

Predictors of invasive cancer of large laterally spreading colorectal tumors: A multicenter study in Japan

Background and Aim

Although colorectal laterally spreading tumors (LSTs) can be classified into four subtypes, the histopathological characteristics are known to differ among these subtypes. We therefore performed a logistic regression analysis to determine whether the risk of pathological T1 cancer of large colorectal LSTs can be predicted based on factors such as endoscopic findings in a large group of patients enrolled in a multicenter study in Japan.

Methods

In the main study, we assessed 1236 colorectal adenomas or early cancers that were classified as LSTs measuring 20 mm or more in diameter and treated endoscopically. Logistic regression analysis was performed to determine whether factors such as the subtype of LST could be used to predict the risk of pathological T1 cancer. A validation study of 356 large colorectal LSTs was conducted to confirm the validity of the results obtained in the main study.

Results

The locations and tumor diameter of the LSTs in the main study were found to differ significantly according to the LST subclassification (P < 0.001). The frequency of pathological T1 cancers was the highest at 36% of LST nongranular pseudodepressed type, followed by 14% of LST nongranular flat‐elevated type, 11% of LST granular nodular mixed type, and 3% of LST granular homogenous type lesions. The risk of pathological T1 cancer was significantly associated with LST subclassification and tumor diameter. The area under the curve (AUC) was high (0.743). In the validation study, the AUC was 0.573.

Conclusions

In patients with large colorectal LSTs resected endoscopically, the risk of pathological T1 cancer can be predicted on the basis of the LST subclassification and tumor diameter.

Risk of colorectal cancer for fecal immunochemistry test-positive, average-risk patients after a colonoscopy

BACKGROUND AND AIM

Because the risk of colorectal cancer has not been well examined in fecal immunochemistry test (FIT)-positive patients who previously underwent colonoscopy, this study aimed to investigate this topic.

METHODS

This was a single-center, observational study of prospectively collected data in Japan. FIT-positive, average-risk patients who underwent colonoscopy were divided into groups as follows: those who never underwent colonoscopy in the past (no colonoscopy group), those with a history of colonoscopy between 6 months and 5 years (0.5- to 5-year colonoscopy group), and those with a history of colonoscopy more than 5 years ago (> 5-year colonoscopy group). We investigated the prevalence of advanced neoplasia and invasive cancer among these groups using multiple logistic regression analysis.

RESULTS

Detection rates of advanced neoplasia in the no colonoscopy group, 0.5- to 5-year colonoscopy group, and > 5-year colonoscopy group were 14.8% (240/1626), 3.9% (13/330), and 6.9% (17/248), respectively. Detection rates of invasive cancer in each aforementioned group were 5.7% (92/1,626), 0.3% (1/330), and 1.2% (3/248), respectively. Odds ratios of advanced neoplasia in the 0.5- to 5-year colonoscopy group and > 5-year colonoscopy were 0.23 (95% confidence interval [CI]: 0.13-0.42) and 0.40 (95% CI: 0.24-0.68), respectively, in multivariate analysis. The odds ratios of invasive cancer in each aforementioned group were 0.05 (95% CI: 0.01-0.37) and 0.19 (95% CI: 0.06-0.61), respectively.

CONCLUSION

Re-screening with the FIT should not be recommended for at least 5 years for average-risk patients after colonoscopy without high-risk neoplasms, because the risks of colorectal cancer are low in such patients.

Clinical outcomes of endoscopic submucosal dissection for laterally spreading tumors involving the dentate line

OBJECTIVE

Endoscopic submucosal dissection (ESD) for laterally spreading tumors (LST) involving the dentate line (LST-DL) is challenging because of the specific anatomical features of the anorectum. This study aimed to evaluate the efficacy and safety of ESD for LST-DL.

METHODS

Consecutive patients with LST-DL who had undergone ESD at our hospital between January 2010 and December 2015 were retrospectively enrolled in this study. Rates of en bloc resection, R0 resection, and complications, pathological characteristics, and tumor recurrence were analyzed and compared with those of LST in the rectum not involving the dentate line (LST-NDL).

RESULTS

Altogether 49 patients with LST-DL (median age 63 years; 39 women; median lesion size 57 mm; median follow-up period of 24 months) and 96 patients with LST-NDL (median age 67 years; 31 women; median lesion size 47 mm; median follow-up period of 31 months) were enrolled. En bloc resection (93.9% [46/49] vs 94.8% [91/96]) and en bloc R0 resection rates (83.7% [41/49] vs 88.5% [85/96]), respectively, for LST-DL and LST-NDL, with no significant differences. However, ESD for LST-DL had a longer procedure time (77 min vs 54 min, P = 0.02), a greater postprocedural perianal pain rate (28.6% vs 0%, P < 0.001), and more anal strictures (4.1% vs 0%, P = 0.04). The complication rates of perforation, bleeding and fever, recurrence rate, and pathological characteristics did not differ between the two groups.

CONCLUSIONS

ESD is a safe and effective therapeutic modality for LST-DL. However, this procedure should be performed by experienced endoscopists and the difficulty needs to be fully considered.

Wide-field endoscopic mucosal resection versus endoscopic submucosal dissection for laterally spreading colorectal lesions: a cost-effectiveness analysis

OBJECTIVE

To compare the cost-effectiveness of endoscopic submucosal dissection (ESD) and wide-field endoscopic mucosal resection (WF-EMR) for removing large sessile and laterally spreading colorectal lesions (LSLs) >20 mm.

DESIGN

An incremental cost-effectiveness analysis using a decision tree model was performed over an 18-month time horizon. The following strategies were compared: WF-EMR, universal ESD (U-ESD) and selective ESD (S-ESD) for lesions highly suspicious for containing submucosal invasive cancer (SMIC), with WF-EMR used for the remainder. Data from a large Western cohort and the literature were used to inform the model. Effectiveness was defined as the number of surgeries avoided per 1000 cases. Incremental costs per surgery avoided are presented. Sensitivity and scenario analyses were performed.

RESULTS

1723 lesions among 1765 patients were analysed. The prevalence of SMIC and low-risk-SMIC was 8.2% and 3.1%, respectively. Endoscopic lesion assessment for SMIC had a sensitivity and specificity of 34.9% and 98.4%, respectively. S-ESD was the least expensive strategy and was also more effective than WF-EMR by preventing 19 additional surgeries per 1000 cases. 43 ESD procedures would be required in an S-ESD strategy. U-ESD would prevent another 13 surgeries compared with S-ESD, at an incremental cost per surgery avoided of US$210 112. U-ESD was only cost-effective among higher risk rectal lesions.

CONCLUSION

S-ESD is the preferred treatment strategy. However, only 43 ESDs are required per 1000 LSLs. U-ESD cannot be justified beyond high-risk rectal lesions. WF-EMR remains an effective and safe treatment option for most LSLs.

TRIAL REGISTRATION NUMBER

NCT02000141.

Clinical outcomes of endoscopic resection for colorectal laterally spreading tumors with advanced histology

BACKGROUND

Colorectal laterally spreading tumors (LSTs) are large, flat neoplasms that are usually treated using different endoscopic techniques based on their morphology, size, and histology. The aim of this study was to evaluate the clinical outcomes of LSTs with advanced histology treated by endoscopic resection.

METHODS

A total of 246 LSTs with advanced histology [i.e., high-grade dysplasia (HGD) and adenocarcinoma (AC)] treated by endoscopic resection [i.e., endoscopic mucosal resection (EMR), EMR-precutting (EMR-P), and endoscopic submucosal dissection (ESD)] were enrolled. Clinicopathological characteristics were collected by review of patient's medical records.

RESULTS

The en bloc resection and R0 resection rates were 75.6% and 85.0%, respectively. The bleeding and perforation rates were 10.2% and 2.4%, respectively. The frequency of cancerous pit pattern and bleeding was significantly higher in LSTs with AC than in LSTs with HGD. The R0 resection rate in LSTs with HGD was significantly higher than that in LSTs with AC. The frequency of cancerous pit patterns in LST cases with submucosal AC was significantly higher than those with intramucosal AC. The mean size of the LSTs was significantly larger in ESD group than in EMR or EMR-P groups. The frequencies of nodular mixed subtype, cancerous pit patterns, and en bloc resection rates were significantly higher in the ESD group than in the EMR or EMR-P groups. However, the frequency of perforation was significantly higher in EMR-P group than in EMR or ESD groups.

CONCLUSIONS

These results indicate that ESD is a more acceptable treatment approach for resection of colorectal LSTs of larger size, with nodular mixed subtype, having a cancerous pit pattern or AC, using either en bloc or curative resection methods, compared to EMR or EMR-P procedures.

Clinicopathological feature and treatment outcome of patients with colorectal laterally spreading tumors treated by endoscopic submucosal dissection

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) is an advanced technique that can be used to treat precancerous and early colorectal neoplasms by facilitating en bloc resection regardless of tumor size. In our study, we investigated the clinicopathological feature and the treatment outcome of patients with colorectal laterally spreading tumors (LSTs) that were treated by ESD.

METHODS

The study enrolled all of 210 patients with colorectal LSTs who underwent ESD. Clinical outcomes were analyzed by retrospectively reviewing medical records.

RESULTS

A cancerous pit pattern (Vi/Vn) was more common in pseudo-depressed (PD) subtype than in flat elevated (FE) subtype. The incidence of adenocarcinoma in the PD subtype and nodular mixed (NM) subtypes was significantly higher than in the homogenous (HG) subtype and FE subtype. The en bloc and R0 resection rates were 89.0% and 85.7%, respectively. The bleeding and perforation rates were 5.2% and 1.9%, respectively. The mean procedure time was much longer in the PD subtype than in the FE subtype. The en bloc resection rate was significantly higher in the NM subtype than in the HG subtype. However, there were no statistically significant differences in mean procedure time, en bloc resection rate, R0 resection rate, bleeding rate, or perforation rate between LST-granular and LST-nongranular types.

CONCLUSIONS

These results indicate that ESD is acceptable for treating colorectal LSTs concerning en bloc resection, curative resection, and risk of complications. Careful consideration is required for complete resection of the PD subtype and NM subtype because of their higher malignant potential.

Invasive pit pattern, macronodule and depression are predictive factors of submucosal invasion in colorectal laterally spreading tumours from a Western population

Background

Laterally spreading tumours are separated in subclasses: granular, homogenous or nodular mixed; and non-granular, flat or pseudodepressed. For every subtype, a proper risk of submucosal invasive cancer has been described in Asian series.

Objective

The aim of the study was to determine the rate of cancer and submucosal invasive cancer in a Western series of endoscopic-resected laterally spreading tumours and their endoscopic predictive factors.

Methods

A total of 374 laterally spreading tumours ≥20 mm were resected by endoscopy in our single centre between 2012-2016. We analysed endoscopic and pathological data from our prospective database, determining the rates of cancer and submucosal invasive cancer according to the subtype of laterally spreading tumour.

Results

The rates of submucosal invasive cancer for granular homogenous, granular nodular mixed, non-granular flat, non-granular pseudodepressed laterally spreading tumours were 4.9%, 15.9%, 3.0% and 19.4%, respectively. Endoscopic mucosal resection was used in 58.0% and endoscopic submucosal dissection in 42.0%. Endoscopic submucosal dissection was associated with a higher rate of en-bloc resection (87.3% vs 26.3%; p < 0.0001), and a lower risk of recurrence (7.6% vs 15.2%; p = 0.026). Adverse event rates were not statistically different (9.5% vs 6.4%, p = 0.26). Predictive endoscopic factors of submucosal invasive cancer were: invasive pit pattern (hazard ratio = 33 (8.81-143.3)), non-granular pseudodepressed laterally spreading tumours (hazard ratio = 11.9 (0.89-146.2)), and granular nodular mixed laterally spreading tumours (hazard ratio = 3.42 (0.99-13.0)).

Conclusions

The risk of submucosal invasive cancer varies according to the laterally spreading tumour subtype. Three factors were associated with submucosal invasion and should justify an endoscopic submucosal dissection: non-granular pseudodepressed laterally spreading tumours, granular nodular mixed laterally spreading tumours subtypes and invasive pit pattern.

Risk factors for procedure-related complications after endoscopic resection of colorectal laterally spreading tumors

Colorectal laterally spreading tumors (LSTs) are large and flat elevated neoplasms with diameters of at least 10 mm. Endoscopic resection of LSTs, with their large size and broad base, is difficult and dangerous compared with the resection of polypoid neoplasms. This study aimed to determine the risk factors for procedure-related complications including bleeding and perforation after endoscopic resection of LSTs.Patients with colorectal LST undergoing endoscopic resection at 5 university hospitals in Honam Province of South Korea were enrolled, and their records about patients, lesions, and procedure parameters associated with the occurrence of complications were reviewed retrospectively. Logistic regression analysis was performed to identify risk factors for complications.The frequency of comorbidities in bleeding group was significantly higher than in the no bleeding group. The frequency of bleeding was significantly higher in lesions with adenocarcinoma than in lesions with low or high-grade dysplasia. The frequency of bleeding was significantly higher in piecemeal resection than in en bloc resection. The frequency of perforation was significantly higher in endoscopic mucosal resection-precutting (EMR-P) than in endoscopic mucosal resection (EMR) or endoscopic submucosal dissection. The mean procedure duration was significantly longer in the perforation group than in the no perforation group. On multivariate analysis, patient comorbidity and histologic grade of the lesion were significant independent risk factors for bleeding, whereas EMR-P was a significant independent risk factor for perforation after endoscopic resection.This study demonstrated that patient comorbidity and histologic grade of lesion were significant independent risk factors for bleeding, and EMR-P was a significant independent risk factor for perforation after endoscopic resection of colorectal LSTs.

Incidence and risk factors of advanced neoplasia after endoscopic mucosal resection of colonic laterally spreading lesions

PURPOSE

To investigate advanced neoplasia (AN) after endoscopic mucosal resection (EMR) of colonic laterally spreading lesions (LSLs).

METHODS

A retrospective study of patients who underwent injection-assisted EMR of colonic LSLs ≥ 10 mm was performed. Primary outcome was overall rate of AN at initial surveillance colonoscopy. Secondary outcomes were the rates of residual AN (rAN) at the EMR site and metachronous AN (mAN), and analysis of risk factors for AN, including effect of surveillance guidance.

RESULTS

Three hundred seventy-four patients underwent successful EMR for 388 LSLs. AN occurred in 66/374 (17.6%) patients on initial surveillance colonoscopy at median follow-up of 364.5 days. Two patients had both rAN and mAN, for a total of 68 instances of AN, including 30/374 (8.0%) cases of rAN and 38/374 (10.2%) cases of mAN. On multivariate analysis, use of piecemeal resection was associated with increased likelihood of residual AN (P = 0.003, OR 9.2, 95% CI 2.1-33.3). Twenty-nine out of thirty cases (96.7%) of rAN were successfully endoscopically managed at surveillance colonoscopy.

CONCLUSIONS

AN occurred in 17.6% of all patients at initial surveillance colonoscopy at a median of 1 year after EMR. Roughly half of the instances of AN were metachronous lesions. Our data support a 1-year surveillance interval after EMR of LSLs ≥ 10 mm with careful inspection of the entire colon, not just the prior resection site.

Genome-wide DNA methylation profiling of primary colorectal laterally spreading tumors identifies disease-specific epimutations on common pathways

Colorectal laterally spreading tumors (LSTs) grow to extremely large size while rarely invade deeply. Also, there is a low tendency to become cancerous. We used the Illumina Human Methylation 450K array to query the main epigenetic difference of LSTs. We built a discovery cohort with 10 matched cases, and a validation cohort with 9 additional matched cases. Our results suggest that LST displays significant decrease in DNA methylation, highlighted by the discovery of 1,018 hypomethylated intergenic regions (IGRs). Comparing to classic differentially methylated probes and regions that overlap transcription starting site and CpG island, IGR-regions were associated more closely with genes involved in functional biological processes and correlated with specific histone modifications. Hypomethylated IGR regions were often annotated as tissue-specific regulatory elements for noncolon tissues and were typically epigenetically silenced in normal colon mucosa. By integration of public data, we defined the commonality and specific epigenetic signatures for adenomas, LSTs and colon adenocarcinomas. Only 435 hypermethylated differentially methylated probes (DMPs) and differentially methylated regions (DMRs) and 517 hypomethylated DMPs and DMRs were shared by the three diseases. However, our pathway-level analysis discovered that genes in four pathways were common target of epimutations in LSTs, adenomas and CRCs. More interestingly, different diseases seem to employ distinct epigenetic insult to disturb specific pathways. Between LST and adenoma, we found eight pathways including Ras signaling and Rap1 signaling pathway were commonly targeted but the epimutation patterns were opposite. Comparison between precancerous conditions and invasive states revealed the key pathways governing the progression to malignancy, including PI3K-Akt pathways.

Impact of retroflexion in the right colon after repeated forward-view examinations

Background and Aim

Right colon polyps can especially be overlooked when they are located on the backs of haustral folds. Previous studies have reported that repeated forward‐view examinations in the right colon were effective in reducing adenoma miss rates. The aim of this study was to clarify the impact of retroflexion in the right colon after repeated forward‐view examinations.

Methods

This multicenter, prospective, observational study was conducted at three institutions in Kumamoto, Japan, between February 2014 and December 2015. Subjects who were over 40 years old and scheduled for colonoscopy were recruited. For the forward view, after cecal intubation, the colonoscope was withdrawn to the hepatic flexure. The colonoscope was sequentially reinserted to the cecum and then withdrawn to the hepatic flexure. For the retroflexion view (RV), the colonoscope was reinserted to the cecum, retroflexed, and then withdrawn to the hepatic flexure. All polyps were resected at the time of detection. The primary outcome of this study was the adenoma miss rate for the repeated forward‐view examinations.

Results

Of the 777 enrolled participants, retroflexion was successful in 730 (94.0%). The repeated forward‐view withdrawal technique detected 291 adenomas, while the third withdrawal in the RV detected 53. The adenoma miss rate for the repeated forward‐view withdrawal was 15.4%. No severe adverse events occurred during retroflexion.

Conclusion

Because adenomas located on potential blind spots can be missed when only using forward‐view examinations, retroflexion in the right colon after repeated forward‐view examinations might improve colonoscopy detection rates.

Colonic angiodysplasia on CT colonography: case report and characteristic imaging findings

Gastrointestinal angiodysplasia represents the cause of 6% of lower gastrointestinal tract bleeding, particularly in the elderly. Because of the common presentation and age range of affected patients, often patients with occult or massive gastrointestinal bleedings are investigated with colonoscopy, in the suspect of colonic cancer. Other methods are capsule enteroscopy, angiography, double-contrast barium enema, computed tomography angiography, and radionuclide scanning. In this contribution, we describe a case of colonic angiodysplasia first suspected during computed tomography colonography performed after an incomplete colonoscopy in a patient with recent anemization. The purpose is to highlight the computed tomography colonography imaging characteristics of this rare finding during such examination performed due to suspected colon carcinoma as a complementary or substitutive method of colonoscopy.

Visual assessment of colorectal flat and depressed lesions by using narrow band imaging

BACKGROUND AND STUDY AIMS

 Visual assessment of laterally spreading tumors non-granular type (LST-NG) and depressed lesions by narrow band imaging (NBI) without magnification has not been studied. We investigated the role of non-magnifying NBI in detecting LST-NG and type IIc lesions on colonoscopy.

PATIENTS AND METHODS

 This retrospective study examined consecutive patients diagnosed as having LST-NG and/or type IIc lesions in our hospital between August 2011 and July 2013. These lesions were classified as "Brownish area (BA)," "Brown only in the margins (O-ring sign)," "Same color as the normal mucosa (SC)," and "Whitish area (WA)" based on their appearance on non-magnifying NBI, and their appearance were compared with their histopathological findings.

RESULTS

 A total of 18 type IIc and 180 LST-NG lesions were analyzed. Among the type IIc lesions, 5 (28 %), 12 (67 %), and 1 (5 %) were classified as BA, O-ring sign, and SC, respectively. Among the LST-NG lesions, 126 (70 %), 26 (14 %), and 28 lesions (16 %) were classified as BA, O-ring sign, and SC, respectively. The IIc lesions were found to have 1 lesion (20 %) with high-grade dysplasia (HGD) in the BA, and 2 lesions (17 %) with invasive cancer (IC) in the O-ring sign group. Among the LST-NG lesions, 27 (21 %) were found to have IC and 49 (39 %), HGD in the BA group; 8 lesions (31 %) had IC and 4 (15 %) had HGD in the O-ring sign group; and 1 lesion (4 %) had IC and 4 (14 %) had HGD in the SC group.

CONCLUSIONS

 Most flat and depressed colorectal lesions were seen on non-magnifying NBI as brown lesions with the exception of some flat lesions that were indistinguishable in color from the adjacent normal mucosa. Some of these flat lesions were also found to have HGD or IC.

Clinicopathological features of laterally spreading colorectal tumors and their association with advanced histology and invasiveness: An experience from Honam province of South Korea: A Honam Association for the Study of Intestinal Diseases (HASID)

Background and aims

Laterally spreading colorectal tumors (LSTs) are divided into four subtypes, including homogenous (HG), nodular mixed (NM), flat elevated (FE), and pseudo-depressed (PD), based on their different endoscopic morphologies. The aim of this study was to investigate the clinicopathological significance of LST subtypes and their association with advanced histology.

Methods

We investigated the medical records of consecutive patients with LST who initially underwent endoscopic resection at five university hospitals in Honam province of South Korea between January 2012 and December 2013. A total of 566LST lesions removed via endoscopic procedures were collected retrospectively for data analysis.

Results

The PD, FE, and NM subtypes were more common in the distal colon and the HG subtype in the proximal colon. The PD subtype had the biggest tumor size, followed by the NM subtype. The frequency of adenomatous pit pattern was significantly higher in the HG, NM, and FE subtypes than in the PD subtype. In contrast, the frequency of cancerous pit pattern was significantly higher in the PD subtype than in the other three subtypes. The rate of advanced histology (high-grade dysplasia or carcinoma) among the LSTs was 36.0%. The risk of advanced histology increased in the distal colon compared with the proximal colon. The PD subtype had the highest incidence of villous component, advanced histology,submucosal invasion, and postprocedure perforation among the four subtypes. The distal colon as tumor site, larger tumor size, PD subtype, and villous component were associated with a statistically significant increased risk of advanced histology.

Conclusion

Our results indicate that the location, size, endoscopic subtype, and histologic component of the LSTs are associated with an increased risk of advanced histology. Therefore, these clinicopathological parameters may be useful in selecting therapeutic strategies in the clinical setting.

Endoscopic treatment outcomes of laterally spreading tumors with a skirt (with video)

BACKGROUND AND AIMS

A "skirt" is a slightly elevated flat lesion with wide pits occasionally observed at the margin of laterally spreading tumors (LSTs). However, the endoscopic treatment outcomes of LSTs with skirts have not been clarified. The aim of this study was to evaluate the endoscopic treatment outcomes of LSTs with skirts.

METHODS

Between February 2006 and March 2014, 996 LSTs were retrospectively examined to assess the clinicopathologic characteristics, procedure time, en bloc resection rate, R0 resection rate, adverse events, and local recurrence rate of endoscopic submucosal dissection (ESD) and of endoscopic resection.

RESULTS

Endoscopic treatment was performed in 35 cases of LSTs with skirts (ratio of ESD to endoscopic piecemeal mucosal resection [EPMR], 32:3) and 961 cases of LSTs without skirts (ratio of ESD to EMR to EPMR to polypectomy, 381:275:114:191). LSTs with a skirt were associated with a significantly higher recurrence rate (P < .01). In both ESD and EPMR, LSTs with a skirt were associated with a higher recurrence rate when compared with LSTs without a skirt (odds ratio, 12.7; P = .032, and odds ratio, 12.3; P = .061, respectively). Multivariate analysis demonstrated that the presence of the skirt and piecemeal resection were significant predictors of local recurrence.

CONCLUSIONS

LSTs with skirts had a significantly higher local recurrence rate after endoscopic treatment compared with LSTs without skirts, especially after EPMR. Therefore, ESD should be recommended as an endoscopic treatment for LSTs with skirts to minimize local recurrence.

Sex-Specific Differences in Colon Cancer when Quality Measures Are Adhered to: Results from International, Prospective, Multicenter Clinical Trials

BACKGROUND

There is no consensus on the relationship between patient sex and the location, stage, and oncologic outcome of colon cancer (CC). We hypothesized that there is a sex-specific difference in the biology and management of CC.

STUDY DESIGN

Our cohort was drawn from a database of patients enrolled in international trials of nodal ultrastaging for nonmetastatic CC. These trials required strict adherence to surgical and pathologic quality measures. Postoperative follow-up included colonoscopy at 1 and 4 years and annual CT scans. Sex-specific differences in tumor biology, location, stage, and recurrence were evaluated by chi-square, Fischer's exact, and independent t-tests.

RESULTS

The cohort included 435 males (median age 69 years) and 423 females (median age 70 years). Females had more right-sided (p = 0.03) and earlier T stage (p = 0.05) tumors, but there was no sex-based difference in pathologic grade, total lymph nodes retrieved, nodal positivity (p = 0.47) or lymphovascular invasion (p = 0.45). The overall 4-year disease-free survival (DFS) was comparable in females and males (77.9% and 77.5%, respectively). By multivariate analysis, only nodal positivity and cancer recurrence affected overall survival (OS) (p = 0.008). Neither sex nor primary tumor affected DFS or OS.

CONCLUSIONS

This is the first prospective study to demonstrate sex-specific differences in location and T stage of CC when surgical and pathologic management adhered to strict quality standards. The predominance of right-sided CC in females suggests that flexible sigmoidoscopy may be inadequate for screening and surveillance. Interestingly, earlier stage and right-sided location did not confer a DFS or OS advantage for women. Additional studies are needed to determine why females have a higher propensity for right-sided lesions and a potential difference in CC biology.

Incidence of interval cancers in faecal immunochemical test colorectal screening programmes in Italy

Objective

In Italy, colorectal screening programmes using the faecal immunochemical test from ages 50 to 69 every two years have been in place since 2005. We aimed to measure the incidence of interval cancers in the two years after a negative faecal immunochemical test, and compare this with the pre-screening incidence of colorectal cancer.

Methods

Using data on colorectal cancers diagnosed in Italy from 2000 to 2008 collected by cancer registries in areas with active screening programmes, we identified cases that occurred within 24 months of negative screening tests. We used the number of tests with a negative result as a denominator, grouped by age and sex. Proportional incidence was calculated for the first and second year after screening.

Results

Among 579,176 and 226,738 persons with negative test results followed up at 12 and 24 months, respectively, we identified 100 interval cancers in the first year and 70 in the second year. The proportional incidence was 13% (95% confidence interval 10–15) and 23% (95% confidence interval 18–25), respectively. The estimate for the two-year incidence is 18%, which was slightly higher in females (22%; 95% confidence interval 17–26), and for proximal colon (22%; 95% confidence interval 16–28).

Conclusion

The incidence of interval cancers in the two years after a negative faecal immunochemical test in routine population-based colorectal cancer screening was less than one-fifth of the expected incidence. This is direct evidence that the faecal immunochemical test-based screening programme protocol has high sensitivity for cancers that will become symptomatic.

Limited Identification of Dual-time-point Positron Emission Tomography/Computed Tomography in Advanced Colorectal Neoplasms

Objective We investigated whether dual-time-point 18-Fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography (PET/CT) could improve the positive predictive value for detecting advanced colorectal neoplasms (cancer, adenoma ≥10 mm or adenoma with high-grade dysplasia). Methods We retrospectively searched for consecutive patients with a known primary cancer, who had a colonic ¹⁸FDG uptake incidentally found by PET/CT, followed by colonoscopy between January 2013 and August 2014. The clinical characteristics including the maximum standardized uptake value (SUVmax) were compared between advanced colorectal neoplasms and non-advanced lesions. Results Forty-eight patients had 51 foci with an incidental focal colorectal uptake of ¹⁸FDG. Among these 51 foci, 28 foci were judged as being advanced neoplasms, whereas 23 foci identified as non-advanced lesions. Four cases were missed by PET/CT: two laterally spreading tumors (LSTs) with intramucosal cancer and two severe adenomas (<10 mm). The positive predictive value for the detection of advanced neoplasms was 55%. The per-spot performance of PET/CT showed that SUVmax was significantly higher in advanced neoplasms than in non-advanced lesions for the early-phase (10.1±4.9 vs. 6.5±3.2, p=0.029) and the delayed-phase (12.0±6.0 vs. 7.4±4.0, p=0.022). However, more importantly, there was a significant overlap of the SUVmax and no significant difference was found in the retention index (19.2±20.1 vs. 16.6±29.4, p=0.767). Conclusion Dual-time-point PET/CT was found to have limited impact for identifying advanced colorectal neoplasms in spite of its high sensitivity and it might therefore not be able to identify either LSTs or small advanced neoplasms.

Large Colorectal Lesions: Evaluation and Management

In the last years, a distinctive interest has been raised on large polypoid and non-polypoid colorectal tumors, and specially on flat neoplastic lesions ≥20 mm tending to grow laterally, the so called laterally spreading tumors (LST). Real or virtual chromoendoscopy, endoscopic ultrasound or magnetic resonance should be considered for the estimation of submucosal invasion of these neoplasms. Lesions suitable for endoscopic resection are those confined to the mucosa or selected cases with submucosal invasion ≤1000 μm. Polypectomy or endoscopic mucosal resection remain a first-line therapy for large colorectal neoplasms, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory.

Non-polypoid colorectal neoplasms: Classification, therapy and follow-up

In the last years, an increasing interest has been raised on non-polypoid colorectal tumors (NPT) and in particular on large flat neoplastic lesions beyond 10 mm tending to grow laterally, called laterally spreading tumors (LST). LSTs and large sessile polyps have a greater frequency of high-grade dysplasia and local invasiveness as compared to pedunculated lesions of the same size and usually represent a technical challenge for the endoscopist in terms of either diagnosis and resection. According to the Paris classification, NPTs are distinguished in slightly elevated (0-IIa, less than 2.5 mm), flat (0-IIb) or slightly depressed (0-IIc). NPTs are usually flat or slightly elevated and tend to spread laterally while in case of depressed lesions, cell proliferation growth progresses in depth in the colonic wall, thus leading to an increased risk of submucosal invasion (SMI) even for smaller neoplasms. NPTs may be frequently missed by inexperienced endoscopists, thus a careful training and precise assessment of all suspected mucosal areas should be performed. Chromoendoscopy or, if possible, narrow-band imaging technique should be considered for the estimation of SMI risk of NPTs, and the characterization of pit pattern and vascular pattern may be useful to predict the risk of SMI and, therefore, to guide the therapeutic decision. Lesions suitable to endoscopic resection are those confined to the mucosa (or superficial layer of submucosa in selected cases) whereas deeper invasion makes endoscopic therapy infeasible. Endoscopic mucosal resection (EMR, piecemeal for LSTs > 20 mm, en bloc for smaller neoplasms) remains the first-line therapy for NPTs, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory and cannot be achieved by means of EMR. After piecemeal EMR, follow-up colonoscopy should be performed at 3 mo to assess resection completeness. In case of en bloc resection, surveillance colonoscopy should be scheduled at 3 years for adenomatous lesions ≥ 1 cm, or in presence of villous features or high-grade dysplasia patients (regardless of the size), while less intensive surveillance (colonoscopy at 5-10 years) is needed in case of single (or two) NPT < 1 cm presenting tubular features or low-grade dysplasia at histology.

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

Improved visibility of colorectal flat tumors using image-enhanced endoscopy

Colonoscopy is considered the gold standard for detecting colorectal tumors; however, conventional colonoscopy can miss flat tumors. We aimed to determine whether visualization of colorectal flat lesions was improved by autofluorescence imaging and narrow-band imaging image analysis in conjunction with a new endoscopy system. Eight physicians compared autofluorescent, narrow-band, and chromoendoscopy images to 30 corresponding white-light images of flat tumors. Physicians rated tumor visibility from each image set as follows: +2 (improved), +1 (somewhat improved), 0 (equivalent to white light), -1 (somewhat decreased), and -2 (decreased). The eight scores for each image were totalled and evaluated. Interobserver agreement was also examined. Autofluorescent, narrow-band, and chromoendoscopy images showed improvements of 63.3% (19/30), 6.7% (2/30), and 73.3% (22/30), respectively, with no instances of decreased visibility. Autofluorescence scores were generally greater than narrow-band scores. Interobserver agreement was 0.65 for autofluorescence, 0.80 for narrow-band imaging, and 0.70 for chromoendoscopy. In conclusion, using a new endoscopy system in conjunction with autofluorescent imaging improved visibility of colorectal flat tumors, equivalent to the visibility achieved using chromoendoscopy.

Serrated and non-serrated precursor lesions of colorectal cancer

Although often viewed as a single disease, colorectal cancer more accurately represents a family of diseases with different precursor lesions. Conventional (tubular, tubulovillous and villous) adenomas are the most common neoplastic lesions occurring in the large intestine. They have adenomatous polyposis coli (APC) mutations and arise from dysplastic aberrant crypt foci, initially as polyclonal lesions. In sporadic tumours, neoplastic progression follows the traditional pathway (chromosomal instability pathway), resulting in CpG island methylator phenotype (CIMP)-negative, microsatellite-stable (MSS), BRAF and KRAS wild-type cancers. Germline mutations in the APC gene lead to familial adenomatous polyposis. Conventional adenomas are also the precursors of Lynch syndrome-associated microsatellite-instable (MSI-high) cancers. Sessile serrated adenoma/polyp (SSA/P) is the principal precursor lesion of the serrated pathway, in which BRAF mutation can lead to colorectal cancer with MSI-high CIMP-high or MSS CIMP-high phenotype. SSA/Ps have been associated with synchronous and metachronous invasive adenocarcinomas as well as so-called interval carcinomas. Serrated polyposis is rare but most likely underdiagnosed. Affected individuals bear an increased but unspecified risk for the development of colorectal cancer; close endoscopic surveillance is warranted. Traditional serrated adenomas (TSAs) are much less common than the other serrated lesions. Cancers originating from TSAs may show KRAS mutation with a CIMP-high MSS phenotype.

Laterally spreading tumors: Limitations of computed tomography colonography

AIM: To prospectively investigate the detection rate of laterally spreading tumors (LSTs) of the colorectum by computed tomography (CT) colonography (CTC).

METHODS: Patients with LSTs measuring ≥ 20 mm detected during colonoscopy were prospectively enrolled in the study. All patients underwent colonoscopy and subsequent CTC on the same day. CTC was performed using multi-detector CT without contrast in the prone and supine positions. Two radiologists blinded to the existence of LSTs read the virtual endoscopic images as well as 2-D images. LSTs were classified into granular and non-granular types based on colonoscopic appearance.

RESULTS: Forty-seven pathologically proven LSTs were evaluated prospectively. Histology included adenomas in 19, mucosal cancers in 19 and T1 cancers in 9. The mean diameter of the LSTs was 35.1 mm. Twenty-eight (60%) LSTs were correctly identified by CTC, and the configuration was similar to the colonoscopic appearance in most cases. Detection rate for the granular type was significantly higher than that for the non-granular type (71% vs 31%, P = 0.013). Detection rate of adenomas was significantly lower than mucosal cancers (32% vs 79%, P = 0.008) and T1 cancers (32% vs 78%, P = 0.042).

CONCLUSION: The detection rate of LSTs by CTC, particularly the non-granular type was not acceptable. Practitioners should be aware of the relatively low detection rate when using CTC.

Colonic distention at screening CT colonography: role of spasmolytic agents and body habitus

Sufficient colonic dilation is important when using CT colonography (CTC) for colorectal cancer screening. We investigated the effect of antispasmodic agents and the patient body habitus on the degree of colonic dilation in screening CTC.We assessed the effect of clinical characteristics [age, gender, body mass index (BMI), and the presence of diverticula] and the use of antispasmodics on colonic distention in 140 patients who underwent CTC for colorectal cancer screening. The CTC was performed in both the supine- and prone positions. Seventy patients received antispasmodics prior to CT examination and the other 70 did not. Colonic distention was scored using a 5-point scale: 1=collapsed, 2=poorly visualized, 3=visualized but underdistended, 4=acceptable, and 5=excellent. Images scored as 4 or 5 were considered to be of diagnostic quality. The mean visual evaluation score was significantly higher in the supine- than the prone position (4.2±0.5 vs. 4.0±0.5, p<0.01). For the supine position, only the use of antispasmodic was statistically associated with sufficient colonic dilation by univariate logistic analysis (odds ratio=2.365, p=0.03). For the prone position, age, BMI, and the use of antispasmodic were statistically associated with sufficient colonic dilation by multivariate analysis. The odds ratio of these parameters was 0.955 (p=0.02), 0.874 (p=0.03), and 2.391 (p=0.02), respectively.We obtained sufficient colonic dilation with an antispasmodic for CTC in both positions. Younger age and a lower BMI were also associated with better colonic dilation in the prone position.

Clinicopathological differences of laterally spreading tumors arising in the colon and rectum

PURPOSE

Laterally spreading tumors (LST) have been recognized worldwide. The aim of our retrospective study was to evaluate the clinicopathological differences of LST arising in the colon and rectum.

METHODS

We investigated the clinical records of consecutive patients with LST that were endoscopically or surgically resected at our hospital between February 2006 and March 2011. LST were classified into three types: granular-homogenous (LST-GH), granular-nodular mixed (LST-GM), and nongranular (LST-NG) types. We also defined the hardly elevated flat lesion with a dilated pit pattern that occurs at the margins of LST as the "skirt." The clinicopathological characteristics of the LST arising in the colon and rectum, including the presence of the skirt, were compared.

RESULTS

A total of 496 colorectal LST in 435 patients were examined. LST-GM was predominant in the rectum, whereas LST-NG was predominant in the colon (p < 0.001). The mean tumor size was larger in the rectum (39.3 ± 17.9 mm) than the colon (25.8 ± 13.6 mm) (p < 0.001). Low-grade dysplasia frequency was lower in the rectum than the colon (4 vs. 37%, p < 0.001). The skirt was identified in 15 lesions (3.0%), with a higher incidence in the rectum than the colon (17 vs. 0.5%, p < 0.001). The skirt was found only in LST-GM.

CONCLUSIONS

A greater proportion of LST-GM, greater mean size, and lower incidence of low-grade dysplasia were found in rectal LST. The skirt was a novel and unique finding, primarily observed in rectal LST-GM cases.

Colonoscopy reduced distal colorectal cancer risk and excess cancer risk associated with family history

PURPOSE

Colonoscopy efficacy at preventing proximal colorectal cancer (CRC) is questioned, and little is known about efficacy in high-risk versus medium-risk populations. We investigated the relationship between colonoscopy screening, family history of colorectal cancer (FHCC), and CRC risk by site.

METHODS

Among 92,078 women of the E3N prospective cohort, 692 CRCs have been diagnosed after a median follow-up of 15.4 years. Cox proportional hazard models estimated adjusted hazards ratios according to subsites of cancer and FHCC.

RESULTS

A personal history of colonoscopy (PHC; n = 37,470) was associated with decreased rectal and distal colon cancer risks (hazard ratio (HR) = 0.57; 95% Confidence Interval (CI) = 0.42-0.78 and HR = 0.37; 95% CI = 0.26-0.52, respectively), but not proximal colon cancer risk (HR = 0.87; 95% CI = 0.64-1.18). In women with no prior colonoscopy, those with FHCC had a 80% higher CRC risk than those without FHCC. In women with previous colonoscopy, CRC risk was similar in women with and without FHCC (p for interaction = 0.04).

CONCLUSIONS

Results showed colonoscopy ability to prevent distal cancers, but not proximal cancers in women. Colonoscopy screening also reduced the excess risk of women with FHCC to that of women with no FHCC.

Colorectal laterally spreading tumors show characteristic expression of cell polarity factors, including atypical protein kinase C λ/ι, E-cadherin, β-catenin and basement membrane component

Colorectal flat-type tumors include laterally spreading tumors (LSTs) and flat depressed-type tumors. The former of which shows a predominant lateral spreading growth rather than an invasive growth. The present study examined the morphological characteristics of LSTs, in comparison with polypoid- or flat depressed-type tumors, along with the expression of atypical protein kinase C (aPKC) λ/ι, a pivotal cell polarity regulator, and the hallmarks of cell polarity, as well as with type IV collagen, β-catenin and E-cadherin. In total, 37 flat-type (24 LSTs and 13 flat depressed-type tumors) and 20 polypoid-type colorectal tumors were examined. The LSTs were classified as 15 LST adenoma (LST-A) and nine LST cancer in adenoma (LST-CA). An immunohistochemical examination was performed on aPKC λ/ι, type IV collagen, β-catenin and E-cadherin. The LST-A and -CA showed a superficial replacing growth pattern, with expression of β-catenin and E-cadherin in the basolateral membrane and type IV collagen along the basement membrane. In addition, 86.6% of LST-A and 55.6% of LST-CA showed aPKC λ/ι expression of 1+ (weak to normal intensity staining in the cytoplasm compared with the normal epithelium). Furthermore, ~45% of the polypoid-type adenomas showed 2+ (moderate intensity staining in the cytoplasm and/or nucleus) and 66.7% of the polypoid-type cancer in adenoma were 3+ (strong intensity staining in the cytoplasm and nucleus). A statistically significant positive correlation was observed between the expression of aPKC λ/ι and β-catenin (r=0.842; P<0.001), or type IV collagen (r=0.823; P<0.001). The LSTs showed a unique growth pattern, different from the expanding growth pattern presented by a polypoid tumor and invasive cancer. The growth characteristics of LST appear to be caused by adequate coexpression of β-catenin, type IV collagen and aPKC λ/ι.

Relationship between frequency of surveillance colonoscopy and colorectal cancer prevention

BACKGROUND AND AIM

The impact of frequent colonoscopy on colorectal cancer (CRC) remains unclear. The present study aimed to determine the relationship between frequency of surveillance colonoscopy and CRC prevention.

METHODS

From April 2010 to April 2011, patients who underwent surveillance colonoscopy after screening and polypectomy in four Japanese endoscopy centers were enrolled in this multicenter historical cohort study. Patients were classified into the following two groups according to the findings of past colonoscopy: a low-risk group (no neoplasia or 1-2 cumulative adenomas <10 mm) and an increased-risk group (advanced adenoma or ≥ 3 cumulative adenomas). The relationship between colonoscopy frequency within the previous 5 years and the prevalence of advanced neoplasia in each group was analyzed using multiple logistic regression.

RESULTS

The final analysis included 2391 patients. In the low-risk group, the odds ratios for advanced adenoma in patients undergoing moderately frequent colonoscopy (2-3 times within the previous 5 years), and frequent colonoscopy (≥ 4 times within 5 years) were 0.33 (95% confidence interval [CI], 0.14-0.81) and 0.21 (95% CI, 0.02-1.60), respectively, compared with infrequent colonoscopy (once or not at all within 5 years). In the increased-risk group, the respective odds ratios were 0.48 (95% CI, 0.28-0.83) and 0.28 (95% CI, 0.12-0.64).

CONCLUSIONS

Although frequent colonoscopy provides benefits against advanced adenoma, the optimal benefit was achieved at 2-3 times. With very frequent colonoscopy (i.e. ≥ 4 times within 5 years), the additional risk reduction for advanced adenoma was relatively small.

Clinicopathological characteristics of laterally spreading colorectal tumor

BACKGROUND AND AIMS

Laterally spreading tumor (LST) is a colorectal pre-cancerous lesion. Previous studies have demonstrated distinct LST clinicopathological characteristics in different populations. This study evaluated clinicopathological characteristics of LST in a Chinese population.

METHODS

A total of 259 Chinese LST patients with 289 lesions were recruited for endoscopic and clinicopathological analyses.

RESULTS

Among these 289 lesions, 185 were granular type (LST-G), whereas 104 were non-granular type (LST-NG). LST-G lesions were further classified into homogeneous G-type and nodular mixed G-type, while LST-NG lesions were further classified into flat elevated NG-type and pseudo-depressed NG-type. Clinically, these four LST subtypes showed distinct clinicopathological characteristics, e.g., lesion size, location, or histopathological features (high-grade intraepithelial neoplasia and submucosal carcinoma). The nodular mixed G-type showed larger tumor size and higher incidence of high-grade intraepithelial neoplasia compared to the other three subtypes, while pseudo-depressed NG-type lesions showed the highest incidence of submucosal carcinoma. Noticeably, no diffidence was detected between the lesions of homogeneous G-type and flat elevated NG-type with regard to the histopathological features. Histology of the malignancy potential was associated with nodular mixed G-type [OR = 2.41, 95% CI (1.09-5.29); P = 0.029], flat elevated NG-type [OR = 3.49, 95% CI (1.41-8.22); P = 0.007], Diameter ≥30 mm [OR = 2.56, 95% CI (1.20-5.20); P = 0.009], Villous adenoma [OR = 2.76, 95% CI (1.01-7.58); P = 0.048] and serrated adenoma [OR = 6.99, 95% CI (1.81-26.98); P = 0.005].

CONCLUSION

Chinese LSTs can be divided into four different subtypes, which show distinct clinicopathological characteristics. Morphology, size and pathological characteristics are all independent predictors of advanced histology.