Smoking and Other Risk Factors in Individuals With Synchronous Conventional High-Risk Adenomas and Clinically Significant Serrated Polyps

Different modifiable risk factors for the development of non-advanced adenoma, advanced adenomatous lesion, and sessile serrated lesions, on screening colonoscopy

The development of premalignant colorectal polyps is significantly influenced by various lifestyle and modifiable risk factors. In our study, we used a large cohort of 9025 patients, who underwent screening colonoscopies at a university hospital, to assess the risk factors associated with the development of three different colorectal cancer precursor lesions: non-advanced adenomas (NAs), advanced adenomatous lesions (ADLs), and sessile serrated lesions (SSLs). Among the participants, 3641 had NAs, 836 had ADLs, and 533 had SSLs. We identified obesity, current smoking, and appendicular skeletal muscle mass as modifiable lifestyle risk factors that increase the development of NAs and ADLs (all P < 0.05). Furthermore, we found a positive correlation between the degree of obesity and an increased risk of developing NAs and ADLs (all P for trend < 0.001), while non-smoking was associated with a decreased risk (P for trend < 0.001 and 0.003, respectively). Smoking was the only modifiable risk factor for developing SSLs (adjusted odds ratio [aOR] 1.58; 95% confidence interval [CI] 1.20-2.07), and the risk was even higher in patients with metabolic syndrome (aOR 1.71; 95% CI 1.05-2.77). Addressing modifiable lifestyle factors such as smoking and obesity could play an important role in reducing the risk of both non-advanced and advanced adenomatous lesions. Smoking cessation is especially important as it is a significant modifiable risk factor for sessile serrated lesions.

Clinicopathologic and endoscopic features of sessile serrated lesions and conventional adenomas: a large inpatient population-based study in China

Objectives

Sessile serrated lesions (SSLs) are precursors of sporadic colorectal cancer (CRC) and have distinct characteristics compared with conventional adenomas (CAs). Several lifestyle and environmental factors may play critical roles in the development of advanced lesions. Our aim is to describe the features of SSLs and CAs and further explore risk factors for advanced lesions.

Methods

This is an observational study that collected demographic, endoscopic, and histological data from the China-Japan Friendship Hospital among the inpatient population with pathologically reported as SSL or CA between 2015 and 2022. We analyzed the clinicopathology and endoscopic differences between SSL alone, CA alone, and synchronous SSL+CA groups, and identified risk factors using multiple regression analysis.

Results

A total of 9236 polyps from 6598 patients were included in the cohort. Patients with SSL+CA were more likely to be older (p=0.008), while individuals with SSL alone had a higher proportion of early-onset polyps (p<0.001), and SSLs were more common in advanced polyps than CAs (p<0.001). A greater proportion of advanced polyps in the SSL and CA groups were diagnosed as Yamada III, Yamada IV, and laterally spreading tumor (p=0.002, p<0.001, respectively), and multiple SSLs and CAs were more represented in nonadvanced polyps than in advanced polyps. In multiple regression analysis, older patients were more likely to develop advanced SSLs (aOR 1.05, 95% CI 1.02-1.09, p=0.005).

Conclusion

SSLs and CAs have diverse demographic, endoscopic, and histological characteristics, and their advanced lesions share different risk factors, which advances the understanding of the etiology and progression of SSLs.

Higher Serrated Polyp Detection Rates Are Associated With Lower Risk of Postcolonoscopy Colorectal Cancer: Data From the New Hampshire Colonoscopy Registry

INTRODUCTION

We used New Hampshire Colonoscopy Registry data to examine the association between postcolonoscopy colorectal cancer (PCCRC) and sessile serrated detection rates (SSLDRs).

METHODS

We included patients with either a colonoscopy or a CRC diagnosis in the NH State Cancer Registry. PCCRC was any CRC diagnosed ≥ 6 months after index examination.

RESULTS

Of 26,901 patients, 162 were diagnosed with PCCRC. The hazard ratio for PCCRC was lowest for patients whose endoscopists had the highest SSLDR quintile (≥6%) (hazard ratio 0.29; 95% confidence interval 0.16-0.50).

DISCUSSION

Endoscopists with higher SSLDRs had lower risks of PCCRC. These data validate SSLDR as a clinically relevant quality measure.

[Obesity and Colorectal Cancer]

The prevalence of obesity has increased significantly worldwide, and this trend is likely to continue in the coming years. There is substantial evidence that obesity plays a crucial role in the development of colorectal cancer. Epidemiological data have consistently demonstrated a correlation between obesity and colorectal cancer. Insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines, and various hormones are plausible biological mechanisms. In addition, obesity has been shown to have an impact on recurrence, treatment success, and overall survival. There are some reports, although the evidence is not conclusive, that weight loss and lifestyle changes such as dietary modification and physical activity can reduce the risk of colorectal cancer. The understanding that obesity is a potentially modifiable risk factor that can affect the incidence and prognosis of colorectal cancer is crucial knowledge that can have an impact on the prevention and treatment of the condition.

Associations of smoking with early- and late-onset colorectal cancer

BACKGROUND

Incidence of colorectal cancer (CRC) in younger adults is increasing in many countries. Smoking is an established risk factor of CRC risk, but evidence on its impact on early-onset CRC (EOCRC) risk is limited. We aimed to evaluate the association of smoking exposure with EOCRC and compare it with late-onset CRC (LOCRC).

METHODS

Smoking history and other known or suspected CRC risk factors were ascertained in detail in personal interviews among 6264 CRC patients and 6866 controls (frequency matched for age, sex, and county of residence) who were recruited in 2003-2020 in the DACHS study (Darmkrebs: Chancen der Verhütung durch Screening [German]; Colorectal Cancer: Chances for Prevention Through Screening [English]), a population-based case-control study from Germany. Associations of smoking with EOCRC (<55 years, 724 cases, 787 controls) and LOCRC (≥55years, 5540 cases, 6079 controls) were estimated using multiple logistic regression.

RESULTS

Smoking exposure was much higher among EOCRC cases than among controls, and strong associations of smoking were observed for both EOCRC and LOCR. Adjusted odds ratios for EOCRC and LOCRC were as follows: current smoking: 1.57 (95% confidence interval [CI] = 1.20 to 2.04, P < .001) and 1.46 (95% CI = 1.28 to 1.67, P < .001); former smoking: 1.39 (95% CI = 1.07 to 1.81, P = .01) and 1.24 (95% CI = 1.13 to 1.36, P < .001); per 10 pack-years: 1.15 (95% CI = 1.05 to 1.27, P < .001) and 1.05 (95% CI = 1.03 to 1.08, P < .001). These patterns were similar for colon and rectum cancer and for early- and late-stage CRC.

CONCLUSION

Smoking is a strong risk factor for both EOCRC and LOCRC.

Serrated Polyp Yield at Colonoscopy in Patients with Positive FIT, Positive mt-sDNA, and Colonoscopy Only: Data from the New Hampshire Colonoscopy Registry

BACKGROUND

Stool-based screening with fecal immunochemical (FIT) or multitarget-stool DNA (mt-sDNA) tests is associated with increased colonoscopy polyp yield. mt-sDNA includes methylated markers, which improve detection of serrated polyps (SP) versus FIT. We compared SP detection in colonoscopies performed for positive FIT or mt-sDNA tests, as well as in colonoscopies without a preceding stool test, using the New Hampshire Colonoscopy Registry, a comprehensive statewide population-based registry.

METHODS

Across the three groups, we compared the frequency of clinically relevant SPs (CRSP: sessile SPs, hyperplastic polyps ≥10 mm, and traditional serrated adenomas). We also compared SP size, histology, number, and bulk (combined sizes).

RESULTS

Our sample included 560 mt-sDNA+ (age ± SD: 66.5 ± 7.9), 414 FIT+ (age ± SD: 66.3 ± 8.8), and 59,438 colonoscopy-only patients (age ± SD: 61.7 ± 8.0). mt-sDNA+ patients were more likely to have a higher yield of CRSPs and CRSP bulk than FIT+ (P < 0.0001) or colonoscopy-only patients (P < 0.0001). More mt-sDNA+ patients had CRSPs without large adenomas or colorectal cancers (17.9% vs. 9.9% of FIT+ and 8% of colonoscopy-only patients). After adjusting for synchronous large adenomas, colorectal cancers, and other risk factors, mt-sDNA+ patients were more likely (OR, 1.82; 95% CI, 1.18-2.85) than FIT+ patients to have CRSPs.

CONCLUSIONS

mt-sDNA+ patients had a higher SP yield than FIT+ or colonoscopy-only patients, particularly in the absence of synchronous large adenomas or colorectal cancer.

IMPACT

Our results suggest that screening with mt-sDNA tests could improve colorectal cancer screening by identifying more patients at increased risk from the serrated pathway.

Establish a Novel Model for Predicting the Risk of Colorectal Ademomatous Polyps: a Prospective Cohort Study

Purpose: To establish and validate a model to determine the occurrence risk of colorectal ademomatous polyps.

Methods: A large cohort of 3576 eligible participants who were treated in the Department of Gastroenterology, the First Affiliated Hospital of Nanjing Medical University from June 2019 to December 2021, were enrolled in our study and divided into discovery and validation cohorts at a ratio of 7:3. LASSO regression method was applied for data dimensionality reduction and feature selection. The nomogram for the occurrence risk of colorectal ademomatous polyps was constructed based on multivariate logistic regression. The predictive performance of the model was evaluated regarding its discrimination, calibration, and clinical applicability.

Results: A total of 10 high-risk factors were independent predictors of the colorectal ademomatous polyps occurrence and incorporated into the nomogram, including older age, male, hyperlipidemia, smoking, high consumption of red meat, high consumption of salt, high consumption of dietary fiber, Helicobacter pylori infection, non-alcoholic fatty liver disease and chronic diarrhea. The model showed favorable discrimination values, with the area under the curve of the discovery and validation cohorts 0.775 (95% confidence interval (CI), 0.755-0.794) and 0.776 (95% CI, 0.744-0.807) respectively. The model was also well-calibrated, with Hosmer-Lemeshow test P = 0.370. In addition, the decision curve analysis revealed that the model had a higher net profit compared with either the screen-all scheme or the screen-none scheme.

Conclusion: In this prospective study, we established and validated a prediction model that incorporated a list of high-risk features related to colorectal ademomatous polyps occurrence, showing favorable discrimination and calibration values.

Long-term Use of Hormone Replacement Therapy is Associated With a Lower Risk of Developing High-risk Serrated Polyps in Women

GOALS/BACKGROUND

Hormone replacement therapy (HRT) and parity have been suggested protective factors against the development of colorectal polyps. However, there are a limited number of studies that have examined the relationship of these factors with high-risk adenomatous polyps (HRAP) or high-risk serrated polyps (HRSP), which may have different causes and therefore implications for screening programs.

STUDY

Data from a cross-sectional study of 1384 women undergoing screening-related colonoscopy between 2008 and 2016 were analyzed. Modified Poisson regression models with robust error variance were used to determine the relative risk of developing adenomatous polyps, serrated polyps, HRAPs, and HRSPs associated with pregnancy, menopausal status, and the use of HRT (duration and type).

RESULTS

Women that used HRT for ≥6 years were at a significantly lower risk of developing a HRSP [risk ratios (RR): 0.53; 95% confidence interval (CI): 0.29-0.97]. Irrespective of the duration of use, the use of HRT that included progesterone alone or with estrogen was associated with a significantly lower risk of developing a HRSP (RR: 0.54; 95% CI: 0.30-0.95). The use HRT with progesterone for ≥6 years was associated with a nonsignificant lower risk of developing a HRSP (RR: 0.42; 95% CI: 0.17-1.04). None of the reproductive factors assessed or HRT were associated with the development of adenomatous polyps or HRAPs.

CONCLUSIONS

The results of this study suggests that the long-term use of HRT, and therapies that include progesterone are associated with a lower risk of developing HRSPs. These results could have implications for targeted screening for serrated polyps among women.

Review article: obesity and colorectal cancer

BACKGROUND

Obesity is a growing global public health problem. More than half the European and North American population is overweight or obese. Colon and rectum cancers are still the second leading cause of cancer death worldwide, and epidemiological data support an association between obesity and colorectal cancers (CRCs).

AIM

To review the literature on CRC epidemiology in obese subjects, assessing the effects of obesity, including childhood or maternal obesity, on CRC, diagnosis, management, and prognosis, and discussing targeted prophylactic measures.

METHOD

We searched PubMed for obesity/overweight/metabolic syndrome and CRC. Other key words included 'staging', 'screening', 'treatment', 'weight loss', 'bariatric surgery' and 'chemotherapy'.

RESULTS

In Europe, about 11% of CRCs are attributed to overweight and obesity. Epidemiological data suggest that obesity is associated with a 30%-70% increased risk of colon cancer in men, the association being less consistent in women. Visceral fat or abdominal obesity seems to be of greater concern than subcutaneous fat obesity, and any 1 kg/m² increase in body mass index confers more risk (hazard ratio 1.03). Obesity might increase the likelihood of recurrence or mortality of the primary cancer and may affect initial management, including accurate staging. The risk maybe confounded by different factors, including lower adherence to organised CRC screening programmes. It is unclear whether bariatric surgery helps reduce rectal cancer risk.

CONCLUSIONS

Despite a growing body of evidence linking obesity to CRC, many questions remain unanswered, including whether we should screen patients with obesity earlier or propose prophylactic bariatric surgery for certain patients with obesity.

Colonoscopy Findings in FIT+ and mt-sDNA+ Patients versus in Colonoscopy-only Patients: New Hampshire Colonoscopy Registry Data

Few studies compare fecal immunochemical test (FIT) and multi-target stool DNA (mt-sDNA) outcomes in practice. We compared colonoscopy yield following FIT+ or mt-sDNA+ tests to colonoscopies without preceding stool tests in the comprehensive population-based New Hampshire Colonoscopy Registry (NHCR). Outcomes were any neoplasia and an ordered outcome: adenocarcinoma, advanced neoplasia (adenoma/serrated polyp ≥ 1 cm/villous/high-grade dysplasia), nonadvanced neoplasia, or normal. Our total sample included 306 mt-sDNA+ (average age ± SD 67.0 ± 7.9), 276 FIT+ (66.6 ± 8.7), and 50,990 colonoscopy-only patients (61.8 ± 8.1). Among average-risk patients (N = 240 mt-sDNA+, N = 194 FIT+, N = 26,221 colonoscopy only), mt-sDNA+ patients had a higher risk for any neoplasia (67.1%) compared with FIT+ (54.6%, P = 0.00098) or colonoscopy (40.8%, P < 0.0001). Severity of findings and histology subtypes differed across the three groups (P < 0.0001 for both), with a higher yield of advanced findings in mt-sDNA+ patients. In particular, clinically relevant serrated polyps (hyperplastic polyps ≥10 mm/traditional serrated adenomas/sessile serrated polyps) were detected at a higher frequency in mt-sDNA+ patients as compared with FIT+ or colonoscopy-only patients. Even after adjustment, patients with positive mt-sDNA [OR = 2.82; 95% confidence interval (CI), 2.00-4.02] or FIT+ tests (OR = 1.67; 95% CI, 1.19-2.36) were more likely to have histologically more advanced findings than colonoscopy alone. At follow-up colonoscopy, mt-sDNA+ tests were more likely to predict neoplasia than FIT+, largely due to increased detection of serrated polyps. Prevention Relevance: Colorectal cancer screening options include colonoscopy and stool-based tests, including the fecal immunochemical test (FIT) and the multi-target stool DNA (mt-sDNA) test which, if positive, must be followed by a colonoscopy. Assessing "real-world" outcomes of colonoscopies following positive stool tests can inform their clinical use. See related Spotlight, p. 417.

Colorectal Neoplasia Detection in Individuals With Positive Multitarget Stool DNA Tests: Data From the New Hampshire Colonoscopy Registry

BACKGROUND

The US Preventive Services Task Force (USPSTF) includes multitarget stool DNA (mt-sDNA) testing as a colorectal cancer (CRC) screening option in average-risk individuals, but data on colonoscopy outcomes after positive mt-sDNA tests in community settings are needed.

AIM

The aim of this study was to investigate colonoscopy outcomes and quality following positive mt-sDNA in the population-based New Hampshire Colonoscopy Registry.

METHODS

We compared colonoscopy outcomes and quality between age-matched, sex-matched, and risk-matched patients from 30 endoscopy practices with and without a preceding positive mt-sDNA test. Main outcomes were colonoscopy findings of CRC, advanced noncancerous neoplasia, nonadvanced neoplasia, or normal examination. Quality measures included withdrawal time, bowel preparation quality, examination completion, and percentage of average-risk individuals with normal colonoscopies receiving a USPSTF-recommended 10 year rescreening interval.

RESULTS

Individuals with positive mt-sDNA tests (N=306, average age 67.0 y; 61.8% female) were significantly more likely than colonoscopy-only patients (N=918, 66.2 y; 61.8% female) to have CRC (1.3% vs. 0.4%) or advanced noncancerous neoplasia (27.1% vs. 8.2%) (P<0.0001). Neoplasia was found in 68.0% of patients having colonoscopy after a positive mt-sDNA test, (positive predictive value, was 68.0%), versus 42.3% of patients with colonoscopy only (P<0.0001). No significant differences in colonoscopy quality measures were observed between cohorts.

CONCLUSIONS

Colonoscopy after a positive mt-sDNA test was more frequently associated with CRC and colorectal neoplasia than colonoscopy alone. Positive mt-sDNA tests can enrich the proportion of colonoscopies with clinically relevant findings. Follow-up recommendations suggest that endoscopists do not inappropriately shorten rescreening intervals in mt-sDNA-positive patients with normal colonoscopy. These findings support the clinical utility of mt-sDNA for CRC screening in community practice.

Colonoscopy utilization and outcomes in older adults: Data from the New Hampshire Colonoscopy Registry

BACKGROUND

Colonoscopy is frequently performed in older adults, yet data on current use, and clinical outcomes of and follow-up recommendations after colonoscopy in older adults are lacking.

METHODS

This was an observational study using the New Hampshire Colonoscopy Registry of adults age ≥65 years undergoing colonoscopy for screening, surveillance of prior polyps, or evaluation of symptoms. The main outcomes were clinical findings of polyps and colorectal cancer and recommendations for future colonoscopy by age.

RESULTS

Between 2009 and 2019, there were 42,611 colonoscopies, of which 17,527 (41%) were screening, 19,025 (45%) surveillance, and 6059 (14%) for the evaluation of symptoms. Mean age was 71.1 years (SD 5.0), and 49.3% were male. The finding of colorectal cancer was rare (0.71%), with the highest incidence among diagnostic examinations (2.4%). The incidence of advanced polyps increased with patient age from 65-69 to ≥85 years for screening (7.1% to 13.6%; p = 0.05) and surveillance (9.4% to 12.0%; p < 0.001). Recommendations for future colonoscopy decreased with age and varied by findings at current colonoscopy. In patients without any significant findings, 85% aged 70-74 years, 61.9% aged 75-79 years, 39.1% aged 80-84 years, and 27.4% aged ≥85 years (p < 0.001) were told to continue colonoscopy. Among patients with advanced polyps, 97.2% aged 70-74 years, 89.6% aged 75-79 years, 78.4% aged 80-84 years, and 66.7% aged ≥85 years were told to continue colonoscopy (p < 0.001).

CONCLUSIONS

Within this comprehensive statewide registry, clinical findings during colonoscopy varied by indication and increased with age. Overall rates of finding advanced polyps and colorectal cancer are low. Older adults are frequently recommended to continue colonoscopy despite advanced age and insignificant clinical findings on current examination. These data inform the potential benefits of ongoing colonoscopy, which must be weighed with the low but known potential immediate and long-term harms of colonoscopy, including cost, psychological distress, and long lag time to benefit exceeding life expectancy.

Healthy lifestyle and the risk of conventional adenomas and serrated polyps: Findings from a large colonoscopy screening population

Evidence on the link between healthy lifestyle and colorectal cancer (CRC) precursors is limited. Our study aimed to examine and compare the associations of healthy lifestyle with CRC precursors in adenoma (AD) -carcinoma and serrated pathways. A total of 24,480 participants including 6,309 ADs, 1,343 serrated polyps (SPs), and 16,828 polyp-free controls were included. A healthy lifestyle score (HLS) was constructed based on five lifestyle factors including cigarette smoking, alcohol drinking, physical activity, diet, and body weight, and categorized into least, slightly, moderately, and most healthy. Multivariable logistic regressions were used to estimate odds ratio (OR) and 95% confidence interval (CI). Inverse dose-response associations between the HLS and risk of ADs were observed (OR per 1 score increment for ADs: 0.82 [95% CI 0.79 - 0.84]; for SPs: 0.73 [95% CI 0.69 - 0.78]), and the association with SPs was more evident than with ADs (OR 0.90, 95% CI 0.85 - 0.96). Compared with participants with the least healthy lifestyle, those with the most healthy lifestyle had 47% lower risk of ADs (OR 0.53, 95% CI 0.47 - 0.59) and 70% lower risk of SPs (OR 0.30, 95% CI 0.23 - 0.39), respectively. These inverse associations were consistent across lesion stage and anatomic subsite and not modified by any stratification factors. The risk advancement periods for the most vs. the least healthy lifestyle were -9.49 years for ADs and -20.69 years for SPs. Our findings help confirm the preventive role of healthy lifestyle in colorectal carcinogenesis.

Chinese consensus on prevention of colorectal neoplasia (2021, Shanghai)

Most patients with colorectal cancer (CRC) were diagnosed in advanced stage and the prognosis is poor. Therefore, early detection and prevention of CRC are very important. As with other cancers, there is also the tertiary prevention for CRC. The primary prevention is etiological prevention, which is mainly the treatment of adenoma or inflammation for preventing the development into cancer. The secondary prevention is the early diagnosis and early treatment for avoiding progressing to advanced cancer. The tertiary prevention belongs to the broad category of prevention, mainly for advanced CRC, through surgical treatment and postoperative adjuvant chemotherapy, radiotherapy, targeted therapy, immunotherapy for preventing tumor recurrence or metastasis. This consensus is based on the recent domestic and international consensus guidelines and the latest progress of international researches in the past five years. This consensus opinion seminar was hosted by the Chinese Society of Gastroenterology and Cancer Collaboration Group of Chinese Society of Gastroenterology, and was organized by the Division of Gastroenterology and Hepatology & Shanghai Institute of Digestive Disease, Renji Hospital, School of Medicine, Shanghai Jiao Tong University. The consensus opinion contains 60 statement clauses, the standard and basis of the evidence-based medicine grade and voting grade of the statement strictly complied with the relevant international regulations and practice.

Expression of adipokine ghrelin and ghrelin receptor in human colorectal adenoma and correlation with the grade of dysplasia

BACKGROUND

Ghrelin is an adipokine that plays an important role in energy balance. Expression of ghrelin and ghrelin receptor has been investigated in different tissues and tumors. Studies regarding expression of ghrelin and ghrelin receptor in colorectal tumors are scarce and no data on expression of ghrelin and its receptor in colorectal adenomas has been published. Ghrelin and ghrelin receptor were highly expressed in colon carcinoma cells while expression was decreased in less differentiated tumors, presuming that ghrelin might be important in early phases of tumorigenesis.

AIM

To investigate the expression of ghrelin and ghrelin receptor in human colorectal adenomas and adjacent colorectal tissue.

METHODS

In this prospective study (conducted from June 2015 until May 2019) we included 92 patients (64 male and 28 female) who underwent polypectomy for colorectal adenomas in the Department of Gastroenterology and Hepatology, “Sestre milosrdnice” Clinical Hospital Center in Zagreb, Croatia. After endoscopic removal of colorectal adenoma, an additional sample of colon mucosa in the proximity of the adenoma was collected for pathohistological analysis. Adenomas were graded according to the stage of dysplasia, and ghrelin and ghrelin receptor expression were determined immunohistochemically in both adenoma and adjacent colon tissue using the polyclonal antibody for ghrelin (ab150514, ABCAM Inc, Cambridge, United States) and ghrelin receptor (ab48285, ABCAM Inc, Cambridge, United States). Categorical and nominal variables were described through frequencies and proportions and the difference between specific groups were analyzed with Fisher’s and Fisher-Freeman-Halton’s method respectively. Spearman's rank correlation coefficient was determined for correlation of expression of ghrelin and ghrelin receptor in adenoma and adjacent colon tissue with the grade of adenoma dysplasia.

RESULTS

Among 92 patients with colorectal adenoma 43 had adenomas with high-grade dysplasia (46.7%). High expression of ghrelin was 7 times more common in high-grade adenoma compared to low-grade adenomas (13.95% to 2.04%, P = 0.048), while the expression of ghrelin in adjacent colon tissue was low. We found no correlation between ghrelin receptor expression in adenoma and adjacent colon tissue and the grade of colorectal adenoma dysplasia. The most significant correlation was found between ghrelin and ghrelin receptor expression in adenomas with high-grade dysplasia (rho = 0.519, P < 0.001).

CONCLUSION

Ghrelin and ghrelin receptor are expressed in colorectal adenoma and adjacent tissue with ghrelin expression being more pronounced in high grade dysplasia as a possible consequence of increased local synthesis.

Self-reported Metabolic Risk Factor Associations with Adenomatous, Sessile Serrated, and Synchronous Adenomatous and Sessile Serrated Polyps

Studies have found a positive association between metabolic risk factors, such as obesity and diabetes, and adenomatous polyps (AP). However, fewer studies have assessed the association between sessile serrated polyps (SSP) or synchronous diagnosis of APs and SSPs (synch polyps). Study participants (N = 1,370; ages 40-85) undergoing screening colonoscopy were enrolled between August 2016 and February 2020. Self-reported metabolic risk factors, including diabetes, hypertension, hyperlipidemia, and overweight/obesity, were evaluated for associations with new diagnoses of APs, SSPs, and synch polyps at the present colonoscopy. Average participant age was 60.73 ± 8.63 (SD) years; 56.7% were female and 90.9% white. In an assessment of individual metabolic risk factors, adjusted for age, sex, race, and smoking status, increased body mass index (BMI; overweight or obese vs. normal BMI of <25 kg/m2) was associated with an increased odds for new onset of colon APs (P trend < 0.001) as was a diagnosis of diabetes [adjusted conditional OR (aCOR) = 1.59 (1.10-2.29)]. No associations were seen between the metabolic risk factors and onset of SSPs. Being obese or hypertensive each increased the odds of new onset of synch polyps with aCOR values of 2.09 (1.01-4.32) and 1.79 (1.06-3.02), respectively. Self-reported risk factors may help assess polyp type risk. Because SSPs and synch polyps are rare, larger studies are needed to improve our understanding of the contribution of these factors to polyp risk. These data lead us to hypothesize that differences in observed metabolic risk factors between polyp types reflect select metabolic impact on pathways to colorectal cancer. PREVENTION RELEVANCE: Self-reported medical history provides valuable insight into polyp risk, potentially enabling the use of larger retrospective studies of colonoscopy populations to assess knowledge gaps. More aggressive colonoscopy screening, critical to colorectal cancer prevention, may be considered in populations of individuals with metabolic risk factors and modifiable lifestyle risk factors.

Why is colorectal cancer increasing in younger age groups in the United States?

Introduction: While colorectal cancer (CRC) incidence and mortality have decreased for older adults, the rates are increasing in adults younger than 50 years of age in the United States as well as globally. In response to strong epidemiologic evidence as well as sophisticated models, the American Cancer Society (ACS) has recommended screening adults for CRC starting at age 45. Understanding the factors associated with the rise of incidence in adults younger than age 50 may help to identify those adults who may be at greatest risk.Areas covered: In this review, we provide an overview of the recent literature and discuss possible explanations for the increase in CRC in young adults including obesity and other recognized CRC risk factors, delay in diagnosis of symptomatic patients (<50 years of age), and review perspectives on the current and future status of the field.Expert opinion: Currently there are little data regarding risk factors for CRC in average risk young adults who are asymptomatic. With potential endorsement of screening at 45 years of age by US Preventive Services Task Force, more data regarding clinical and molecular risk factors associated with CRC in young adults will be available.

Nicotine-derived NNK induces the stemness enrichment of CRC cells through regulating the balance of DUSP4-ERK1/2 feedback loop

Cigarette smoking has been considered as an independent risk factor for colorectal cancer (CRC) initiation and progression. In this study, we found that cigarette smoking was significantly associated with poor CRC differentiation (P = 0.040). Since studies have indicated that poorly differentiated tumors are more aggressive and metastasize earlier, leading to poorer prognosis; and cancer stem cells (CSCs) are largely responsible for tumor differentiation state, here we observed that the exposure of nicotine-derived 4-(methylnitrosamino)- 1-(3-pyridyl)- 1-butanone (NNK) promoted cell sphere formation and the expression of the stem cell markers, CD44, OCT4, C-MYC and NANOG in HCT8 and DLD-1 cells. Further colony formation assay, CCK-8 assay and tumor-bearing experiment showed that NNK exposure significantly increased the proliferative and growth ability of CRC cells. In mechanism, we found that NNK-activated ERK1/2 played an important role in enrichment of CRC stem cells and the up-regulation of DUSP4, a major negative regulator of ERK1/2. Moreover, DUSP4 up-regulation was essential for maintaining NNK-activated ERK1/2 in an appropriate level, which was an required event for NNK-induced stemness enrichment of CRC cells. Taken together, our findings provided a possible mechanistic insight into cigarette smoking-induced CRC progression.

Colonoscopy Outcomes in Average-Risk Screening Equivalent Young Adults: Data From the New Hampshire Colonoscopy Registry

INTRODUCTION

Data are needed to further inform the American Cancer Society recommendation to begin colorectal cancer (CRC) screening at age 45. We used the New Hampshire Colonoscopy Registry to compare the prevalence of advanced neoplasia (AN) in an "average-risk screening equivalent" group aged 45-49 years with patients aged 50-54 years and older receiving screening colonoscopy.

METHODS

Colonoscopies in adults older than 50 years of age usually have diagnostic indications of varying clinical significance. We combined patients older than 50 years with diagnostic indications (abdominal pain and constipation) expected to yield AN prevalence similar to screening low AN risk and those with a screening indication to form an "average-risk screening equivalent" group. We excluded high-risk indications (e.g., bleeding and anemia), surveillance examinations, and patients with a first-degree family history of CRC, incomplete examinations, and poor bowel preparation. We calculated prevalence/adjusted risks for AN (≥1 cm, villous, high-grade dysplasia, and CRC) and clinically significant serrated polyps (large [≥1 cm] hyperplastic polyps, sessile serrated polyp, traditional serrated adenomas, and proximal hyperplastic polyp ≥ 5 mm).

RESULTS

In our sample (n = 40,812), AN prevalence was as follows: <40 years (1.1%), 40-44 years (3.0%), 45-49 years (3.7%), 50-54 years (3.6%), 55-59 years (5.1%), and 60+ years (6.7%) (P < 0.0001 across all groups). The prevalence of both AN and clinically significant serrated polyp was similar in the 45-49 and 50-54 years' age groups. Furthermore, the prevalence of AN increased significantly in the 40-44 group as compared to that in the <40 years group. Adjusted analyses confirmed these results. The diagnostic indications considered to have low risk were not predictive of AN.

DISCUSSION

New Hampshire Colonoscopy Registry data, demonstrating an increase in AN risk starting at age 40 and a similar prevalence for individuals aged 45-49 and those ages 50-54, provide clinically useful evidence for optimization of prevention and the age to start screening. However, this is a complex issue involving additional considerations that will need to be addressed.

Colorectal Cancer Screening for the Serrated Pathway

Serrated polyps are classified into hyperplastic polyps, sessile serrated adenomas/polyps, and traditional serrated adenomas. Although all serrated polyps share characteristic colonic crypts serrations, distinguishing hyperplastic polyps from sessile serrated adenomas/polyps is challenging. Traditional serrated adenomas are cytologically dysplastic lesions; sessile serrated adenomas/polyps develop cytologic dysplasia as they progress to colorectal cancer. A flat and pale appearance of serrated polyps may make detection difficult. Endoscopic mucosal resection has higher rates of complete resection. Close surveillance is recommended for sessile serrated adenomas/polyps, sessile serrated adenomas/polyp with dysplasia, hyperplastic polyps ≥10 mm, and traditional serrated adenomas.

Prevalence and risk factors for colorectal polyps in a Chinese population: a retrospective study

The incidence of colorectal polyps is rising. Certain types of polyps are considered to be the precursor lesions for colorectal cancers. To investigate the prevalence and related factors of colorectal polyps in Chinese subjects, we first performed a cross-sectional study. A total of 3066 subjects were documented, and the prevalence of colorectal polyps was 18.1%. Then we evaluated the incidence and risk factors of polyps via a retrospective cohort study in the same population. 561 subjects who received at least twice surveillance colonoscopies with available reports during the study period and had no polyp at the first endoscopy were included in the retrospective cohort study, of whom 19.1% developed colorectal polyps. Regular smoking was independently associated with the presence and development of colorectal polyps. Further analyses indicated that polyps were associated with smoking status, daily cigarette consumption, and drinking habit. Moreover, smoking tends to be more relavent to rectal, small and single polyp. In conclusion, colorectal polyp is a common disease in China. Exploring the epidemiology and risk factors may improve the prevention of colorectal polyps, even colorectal cancer.

Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia

In addition to the adenoma to carcinoma sequence, colorectal carcinogenesis can occur via the serrated pathway. Studies have focused on clarification of categories and molecular features of serrated polyps, as well as endoscopic detection and risk assessment. Guidelines from the World Health Organization propose assigning serrated polyps to categories of hyperplastic polyps, traditional serrated adenomas, and sessile serrated lesions (SSLs). Traditional serrated adenomas and SSLs are precursors to colorectal cancer. The serrated pathway is characterized by mutations in RAS and RAF, disruptions to the Wnt signaling pathway, and widespread methylation of CpG islands. Epidemiology studies of serrated polyps have been hampered by inconsistencies in terminology and reporting, but the prevalence of serrated class polyps is 20%-40% in average-risk individuals; most serrated polyps detected are hyperplastic. SSLs, the most common premalignant serrated subtype, and are found in up to 15% of average-risk patients by high-detecting endoscopists. Variations in rate of endoscopic detection of serrated polyps indicate the need for careful examination, with adequate bowel preparation and sufficient withdrawal times. Risk factors for SSLs include white race, family history of colorectal cancer, smoking, and alcohol intake. Patients with serrated polyps, particularly SSLs and traditional serrated adenomas, have an increased risk of synchronous and metachronous advanced neoplasia. Surveillance guidelines vary among countries, but SSLs and proximal hyperplastic polyps require special attention in assignment of surveillance interval-especially in light of concerns regarding incomplete detection and resection.