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

Post-colonoscopy colorectal cancer in the Western Australian population: analysis of patient, histopathological and molecular characteristics

BACKGROUND

Post-colonoscopy colorectal cancer (PCCRC), defined as colorectal cancer (CRC) detected after a cancer-negative colonoscopy, represents a key quality indicator for CRC detection and prevention. While most PCCRC is attributed to missed lesions, few studies examine pathologic and molecular characteristics of PCCRC to assess for possible de novo cancer formation causing PCCRC.

AIM

The aim of this study was to identify cases of PCCRC where prior colonoscopy was adequate (A-PCCRC) versus inadequate (I-PCCRC) and compare both subtypes with spontaneous CRC (sCRC) in terms of patient factors, histopathology and molecular characteristics.

METHODS

This was a 12-year retrospective population-based study using a data set from the Western Australian Cancer Registry between 2000 and 2011. A-PCCRCs were identified by excluding lesions likely missed due to procedural factors or incomplete prior resection at index colonoscopy performed within 3-36 months of cancer diagnosis. Histopathological review and next-generation sequencing were conducted on subsets of patients with A-PCCRC and sCRC. Statistical analysis included univariable and multivariable regression models and chi-squared and Wilcoxon rank sum tests.

RESULTS

A total of 524 (3.81%) cases of PCCRC were identified out of 13 757 cases of CRC; 272 were A-PCCRC (1.98%) and 252 I-PCCRC (1.83%). Female sex, older age and proximal location were associated with A-PCCRC. Mutations in the PIK3CA gene were less common in A-PCCRC compared to sCRC.

CONCLUSION

A significant percentage of PCCRC occurred despite adequate prior colonoscopy. Missed sessile serrated lesions may contribute to many of these cases; however, further studies are required to examine possible de novo cancer as a cause of PCCRC that may involve unique biological pathways.

Gender and sex differences in colorectal cancer screening, diagnosis and treatment

Males have a higher incidence and mortality rate from colorectal cancer (CRC) compared with females. This review examines the reasons for these differences, including risk factors, screening participation, interpretation of screening tests, presentation and tumour types, pathophysiology (particularly the impact of sex hormones on tumour-related gene expression, microsatellite instability, micro-RNA expression, and the tumour microenvironment), and the efficacy and toxicity of treatment. Sex differences in hormones and body composition are responsible for some of the sexual dimorphism in CRC incidence and outcomes, particularly the pathophysiology, CRC presentation, the pharmacokinetics of cytotoxic therapies, and the impact of treatment on outcomes. However, gender differences also play a role, affecting risk factors, access to or participation in screening and treatment, and patients' experience of treatment (e.g. adverse events and sequelae). Sex and gender issues warrant further investigation in CRC to optimise treatment outcomes for patients.

Sessile Serrated Lesions: Searching for the True Prevalence and Risk Factors in China

Background/Aims

Growing recognition identifies sessile serrated lesions (SSL) as colorectal cancer (CRC) precursors. However, the SSL detection rate remains debatable and lacks a definitive consensus. Additionally, understanding the influencing factors in SSL development is limited. We aim to retrospectively analyze the true prevalence and risk factors of SSL in China.

Materials and Methods

This retrospective study collected medical data from patients who underwent colonoscopy at the Endoscopy Center of Shanghai East Hospital affiliated with Tongji University between March 1, 2019 and February 28, 2022. Data were sourced through the electronic medical record system and included information such as age, sex, lesion location, number, and pathology. This study predominantly focused on the detection rate and the clinical and endoscopic features of SSL.

Results

Of 72 287 colonoscopies in 3 years, 3905 cases were histologically confirmed as SSL. Among them, 2290 (58.6%) were male, and 1615 (41.4%) were female. The overall SSL detection rate was 5.40%, slightly surpassing Asian/Chinese averages but lower than Western rates. Males had a higher SSL detection rate (6.1%) than females (4.6%). Univariate analysis revealed a significant association between SSL with dysplasia/adenocarcinoma (SSL-D/AD) and obesity (Body Mass Index, BMI ≥ 24), CRC family history, and hypertension. After multivariable logistic regression, only obesity (BMI ≥ 24) remained a statistically significant independent risk factor for SSL-D/AD.

Conclusions

The SSL detection rate at our center is 5.4% and increases with age. Males have a significantly higher detection rate than females. Our findings suggest that endoscopists should consider risk factors for SSL-D/AD, such as obesity, CRC family history, and hypertension.

Prevalence and predictive factors of colorectal sessile serrated lesions in younger individuals

BACKGROUND

Sessile serrated lesions (SSLs) are obscured lesions predominantly in the right-sided colon and associated with interval colorectal cancer; however, their prevalence and risk factors among younger individuals remain unclear.

METHODS

This retrospective study enrolled individuals who underwent index colonoscopy. The primary outcome was the SSL prevalence in the younger (<50 years) and older (≥50 years) age groups, while the secondary outcomes included clinically significant serrated polyps (CSSPs). Multivariable logistic regression was employed to identify predictors.

RESULTS

Of the 9854 eligible individuals, 4712 (47.8%) were categorized into the younger age group. Individuals in the younger age group exhibited lower prevalences of adenomas (22.6% vs. 46.2%; P<0.001) and right-sided adenomas (11.2% vs. 27.2%; P<0.001) compared with their older counterparts. However, both groups exhibited a similar prevalence of SSLs (7.2% vs. 6.5%; P=0.16) and CSSPs (10.3% vs. 10.3%;P=0.96). Multivariable analysis revealed that age 40-49 years (odds ratio [OR] 1.81, 95%CI 1.01-3.23), longer withdrawal time (OR 1.17, 95%CI 1.14-1.20, per minute increment), and endoscopist performance (OR 3.35, 95%CI 2.44-4.58) were independent predictors of SSL detection in the younger age group. No significant correlation was observed between adenoma and SSL detection rates among endoscopists.

CONCLUSION

SSLs are not uncommon among younger individuals. Moreover, diligent effort and expertise are of paramount importance in SSL detection. Future studies should explore the clinical significance of SSLs in individuals of younger age.

National Trends in the Incidence of Sporadic Malignant Colorectal Polyps in Young Patients (20-49 Years): An 18-Year SEER Database Analysis

Background and Objectives: Conflicting guidelines exist for initiating average-risk colorectal cancer screening at the age of 45 years. The United States Preventive Services Task Force (USPSTF) changed its guidelines in 2021 to recommend initiating screening at 45 years due to an increasing incidence of young-onset colorectal cancer. However, the American College of Physicians (ACP) recently recommended not screening average-risk individuals between 45 and 49 years old. We aim to study the national trends in the incidence of sporadic malignant polyps (SMP) in patients from 20 to 49 years old. Materials and Methods: We analyzed the Surveillance, Epidemiology, and End Results database (2000-2017) on patients aged 20-49 years who underwent diagnostic colonoscopy with at least a single malignant sporadic colorectal polyp. Results: Of the 10,742 patients diagnosed with SMP, 42.9% were female. The mean age of incidence was 43.07 years (42.91-43.23, 95% CI). Approximately 50% of malignant polyps were diagnosed between 45 and 49 years of age, followed by 25-30% between 40 and 45. There was an upward trend in malignant polyps, with a decreased incidence of malignant villous adenomas and a rise in malignant adenomas and tubulovillous adenomas. Conclusions: Our findings suggest that almost half of the SMPs under 50 years occurred in individuals under age 45, younger than the current screening threshold recommended by the ACP. There has been an upward trend in malignant polyps in the last two decades. This reflects changes in tumor biology, and necessitates further research and support in the USPSTF guidelines to start screening at the age of 45 years.

Colorectal adenomatous and serrated polyps in rural South Australia: who, why, what and where?

BACKGROUNDS

The adenoma-carcinoma and serrated pathways offer a window of opportunity for the removal of pre-malignant polyps and prevention of colorectal cancer (CRC) through the use of colonoscopy. The aim of this study was to investigate variation in polyp incidence in different age groups, gender and indications for undertaking colonoscopy. We also address histological types of polyps found and where in the bowel they are located.

METHODS

This study is based on the colonoscopy data collected prospectively over a one-year period in multiple South Australian rural centres, 24 general surgeons contributed to this study. All histopathology results were subsequently entered into the dataset.

RESULTS

A total of 3497 colonoscopies were performed, with a total of 2221 adenomatous and serrated polyps removed. Both serrated and adenomatous polyps were more common in the distal colon. Patients of male gender, aged 70 years and over and with an indication of polyp surveillance had higher adenoma and serrated polyp detection rates (ADR and SPDR). Patients aged 40-49 years old who underwent colonoscopy for positive faecal occult blood had an ADR and SPDR of 25.0% and 6.3%, respectively.

CONCLUSIONS

This study has shown variation in ADR and SPDR depending on age, gender and indication for colonoscopy. This variation will help further develop key performance indicators in colonoscopy. The high ADR and SPDR in patients aged 40-49 years old whom underwent colonoscopy for positive faecal occult blood may support lowering the age of commencement of CRC screening in Australia.

Strategies to minimise the current disadvantages experienced by women in faecal immunochemical test-based colorectal cancer screening

Currently, women are disadvantaged compared to men in colorectal cancer (CRC) screening, particularly in programmes that use faecal immunochemical tests for haemoglobin (FIT) followed by colonoscopy. Although there is no single cause for all the known disadvantages, many can be attributed to the ubiquitous finding that women have lower faecal haemoglobin concentrations (f-Hb) than men; there are many plausible reasons for this. Generally, a single f-Hb threshold is used in CRC screening programmes, leading to lower positivity for women than men, which causes poorer outcomes for women, including lower CRC detection rate, higher interval cancer (IC) proportion, and higher CRC mortality. Many of the now widely advocated risk scoring strategies do include factors taking account of sex, but these have not been extensively piloted or introduced. Using different f-Hb thresholds for the sexes seems advantageous, but there are difficulties, including deciding which characteristic should be selected to achieve equivalency, for example, positivity, IC proportions, or specificity. Moreover, additional colonoscopy resources, often constrained, would be required. Governments and their agencies should be encouraged to prioritise the allocation of resources to put simple strategies into practice, such as different f-Hb thresholds to create equal positivity in both sexes.