Genetic Obesity Variants and Risk of Conventional Adenomas and Serrated Polyps

BACKGROUND

Higher body mass index (BMI) is associated with increased risk of colorectal cancer. How genetically predicted BMI may be associated with colorectal cancer precursors is unknown.

AIMS

Our objective was to quantify the association of genetically predicted and measured BMI with risk of colorectal cancer precursors.

METHODS

We evaluated the association of genetically predicted and measured BMI with risk of conventional adenomas, serrated polyps, and synchronous polyps among 27,426 participants who had undergone at least one lower gastrointestinal endoscopy in the Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-up Study. Genetic risk score was derived from 97 BMI-related single nucleotide polymorphisms. Multivariable logistic regression evaluated each polyp subtype compared to non-polyps.

RESULTS

For conventional adenomas, the OR per 2-kg/m² increase was 1.03 (95% CI, 1.01-1.04) for measured BMI and 0.98 (95% CI, 0.88-1.10) for genetically predicted BMI; for serrated polyps, the OR was 1.06 (95% CI, 1.04-1.08) and 1.04 (95% CI, 0.90-1.20), respectively; for synchronous polyps, the OR was 1.10 (95% CI, 1.07-1.13) and 1.09 (95% CI, 0.89-1.34), respectively. Genetically predicted BMI was associated with synchronous polyps in women (OR = 1.37, 95% CI: 1.05-1.79).

CONCLUSION

Genetically predicted BMI was not associated with colorectal cancer precursor lesions. The confidence intervals were wide and encompassed those for measured BMI, indicating that null findings may be due to insufficient power.

Disparate age and sex distribution of sessile serrated lesions and conventional adenomas in an outpatient colonoscopy population-implications for colorectal cancer screening?

PURPOSE

Colorectal cancer (CRC) is increasingly diagnosed in individuals aged < 50 years, resulting in advocacy of screening from age 45 years. Despite existing knowledge associating CRC with conventional adenomas, the significance of sessile serrated lesions (SSLs) on the burden of CRC is less detailed. We aimed to provide contemporary estimates for SSL prevalence and examine patient and procedure factors associated with SSL detection.

METHODS

Retrospective observational study examining associations between SSL and conventional adenoma detection, polyp histopathology, patient, and procedure characteristics in an outpatient colonoscopy unit over 12 months.

RESULTS

From 2097 colonoscopies, SSL detection was 13.8% overall and 12.5% in patients < 50 years. SSLs were mostly proximal in location (64%), and SSL detection was significantly higher in females compared with males (16.2% vs. 11.7%, p = 0.003), particularly in those < 50 years (16.8% vs. 8.6%, p < 0.001). In multivariable analysis, SSL detection was associated with female sex (adjusted odds ratio [aOR] 1.48, 95% confidence interval [CI] 1.15-1.91), synchronous conventional adenoma detection (aOR 1.36, 95% CI 1.04-1.78) and BMI ≥ 25 kg/m² (aOR 1.34, 95% CI 1.02-1.77). Conventional adenoma detection was 33.6% and associated with age ≥ 50 years (aOR 3.57, 95% CI 2.84-4.47) and synchronous SSL detection (aOR 1.36, 95% CI 1.03-1.79).

CONCLUSIONS

We observed age and sex disparities in polyp types and prevalence in this outpatient colonoscopy population. SSLs were most prevalent in females aged < 50 years, suggesting a potential increased susceptibility of young females to SSLs and CRC. Our findings may have implications for the design of CRC screening programs.

Location of colorectal adenomas and serrated polyps in patients under age 50

BACKGROUND

The incidence of colorectal cancer, especially located in distal colorectum, is rising markedly in young patients. Conventional adenomas and serrated polyps have been widely recognized as precursors of colorectal cancer.

AIM

To investigate the correlation of polyp feature with polyp location in patients under age 50.

METHOD

Patients under age 50 who had received colonoscopy were included from 2010 to 2018. Clinical data including number, location, size, and histopathology of polyps were collected. Odd ratios and 95% confidence interval of adenomas with their location were calculated.

RESULT

In total, 25,636 patients aged 18-49 were enrolled, among which 4485 patients had polyps, with polyp detection rate of 17.5%. A total of 2484 and 2387 patients had conventional adenomas and serrated polyps, respectively. 76.0% advanced adenomas and 69.5% ≥ 10-mm serrated polyps were located in the distal colorectum. The detection rate of advanced adenomas was higher in patients aged 45-49. Patients with adenomas especially advanced adenomas in the distal colorectum were more likely to have advanced adenoma in the proximal colon.

CONCLUSION

Among patients under age 50, advanced adenomas and ≥ 10-mm serrated polyps were predominantly in the distal colorectum. Advanced adenomas tended to be found in patients aged 45-49. Our results might explain the rising trend of distal colorectal cancer and emphasize the necessity for colonoscopy screening among these populations.

Update in Surveillance Recommendations in Individuals With Conventional Adenomas

PURPOSE OF REVIEW

Conventional adenomas, which are precursors to almost 70% of colorectal carcinomas, are found in more than one-third of screening colonoscopies. Surveillance recommendations, based on adenoma size, histology, and number, have evolved over the years and are currently reflective of index adenoma categorization as either low-risk (LRA) or high-risk (HRA). In this review, recent guideline recommendations as well as primary data that have helped to shape these recommendations are presented.

RECENT FINDINGS

Recent data have demonstrated that individuals with HRA on index exams may be at increased risk for CRC while those with LRA may have a minimal long-term risk for CRC, similar to those adults with normal index exams. Furthermore, the quality of the index exams is important for minimizing CRC risk. While individuals with HRA may require close surveillance intervals of 3 years, those with LRA or normal exams may need longer such as 10-year follow-up.

Diagnostic and reporting issues of preneoplastic polyps of the large intestine with early carcinoma

Premalignant polyps of the large intestine are common specimens in surgical pathology. They consist of several different subtypes identifiable by histological criteria that are associated with different molecular characteristics and with the development of different types of colorectal carcinoma. The most common of these is the conventional adenoma, which most commonly leads to carcinomas with a low degree of methylation (CIMP-L) that are microsatellite stable. In Lynch syndrome patients these polyps lead to CIMP-L carcinomas that are microsatellite instable. The second most common is the sessile serrated adenoma, which leads to carcinomas with a high degree of methylation (CIMP-H) that may be either microsatellite stable or instable. The least common premalignant polyp is the traditional serrated adenoma, which can lead to either CIMP-L or CIMP-H carcinomas, most often microsatellite stable. This paper will review the histological features of these lesions, discuss problems in diagnosis and discuss the role of histology in management.

Epidemiology of Colorectal Adenomas and Histopathological Assessment of Endoscopic Specimens in the Colorectum

BACKGROUND

Colorectal cancer is one of the most frequently observed neoplasms in the world. It develops from intraepithelial neoplasia of the colorectal mucosa, and these precursor lesions are also known as adenoma. As the precursor lesion is known and can be detected easily, efficient screening strategies are available for a reliable prevention of colorectal adenocarcinoma, e.g. by colonoscopy.

METHODS

Literature databases (PubMed) were searched selectively for the keywords 'colorectal adenoma', 'epidemiology', and 'resection techniques'. The results are presented in the following text, also taking into account our own experience and the current S3 guidelines.

RESULTS

Endoscopic resection samples are one of the specimens most frequently assessed by pathologists. Therefore, gastroenterologists expect standardized and well-structured pathology reports, stating relevant information concerning the removed lesions and recommendations for clinical management. These aspects are summarized in the evidence-based S3 guideline.

CONCLUSION

As a consequence of colorectal adenoma resection during screening procedures, the carcinoma incidence is decreasing. For further advancements in successful prevention, knowledge of different precursor lesions (conventional adenoma, serrated adenoma) is important, but also structured communication between the different disciplines engaged in colorectal cancer screening.

Histology subtypes and polyp size are associated with synchronous colorectal carcinoma of colorectal serrated polyps: a study of 499 serrated polyps

Sessile serrated adenomas (SSA) and traditional serrated adenomas (TSA) are considered as precursors of colorectal cancer, and are often diagnostic challenges. Their true prevalence is masked by significant inter-observer variations. To investigate the true prevalence and synchronous colorectal carcinoma (sCRC) of colorectal serrated polyps (CSP) and their associated factors, we first retrospectively identified all colorectal polyps collected at our institution between June 1995 and May 2013. After centrally reclassifying all CSP to reduce inter-observer variations, Chi-square tests and logistic regression analyses were used to analyze the potential factors. Among the included 5501 colorectal polyps, 499 CSP of 428 patients were identified and studied, including 353 hyperplastic polyps (HP, 70.7%), 80 SSA (16.0%), 61 TSA (12.2%) and 5 mixed polyp (1.0%). Diagnostic disagreements were found in 68 CSP (13.63% of CSP). SSA and TSA were more often larger than 5 mm and in proximal colon than HP. SSA were also more likely associated with older age (p=0.005), size ≥5 mm (p<0.001) and ≥3 polyps (p=0.004) than HP in distal colon, but only more likely associated with older age (p=0.006) in proximal colon. Multivariate regression analysis demonstrated that CSP with sCRC, compared with CSP without sCRC, were linked to CSP size ≥1 cm (vs <1 cm, odds ratio [OR] 4.412, 95% confidence interval [CI] 1.684-11.556, P=0.003) and a diagnosis of SSA or TSA (vs HP, OR 6.194, 95% CI 1.870-20.513, P=0.003 and OR 6.754, 95% CI 1.981-23.028, P=0.002, respectively), but not age, gender, polyp number and polyp shape. SSA and TSA are similarly often associated with sCRC (P=0.460). In conclusion, histology subtypes and polyp size may serve as markers for sCRC of CSP. SSA and TSA may warrant careful endoscopic examinations and similar follow-up intervals.