Prevalence of serrated lesions, risk factors, and their association with synchronous advanced colorectal neoplasia in asymptomatic screened individuals

Prevalence, risk factors, and BRAF mutation of colorectal sessile serrated lesions among Vietnamese patients

BACKGROUND

Sessile serrated lesions (SSLs) are considered precancerous colorectal lesions that should be detected and removed to prevent colorectal cancer. Previous studies in Vietnam mainly investigated the adenoma pathway, with limited data on the serrated pathway.

AIM

To evaluate the prevalence, risk factors, and BRAF mutations of SSLs in the Vietnamese population.

METHODS

This is a cross-sectional study conducted on patients with lower gastrointestinal symptoms who underwent colonoscopy at a tertiary hospital in Vietnam. SSLs were diagnosed on histopathology according to the 2019 World Health Organization classification. BRAF mutation analysis was performed using the Sanger DNA sequencing method. The multivariate logistic regression model was used to determine SSL-associated factors.

RESULTS

There were 2489 patients, with a mean age of 52.1 ± 13.1 and a female-to-male ratio of 1:1.1. The prevalence of SSLs was 4.2% [95% confidence interval (CI): 3.5-5.1]. In the multivariate analysis, factors significantly associated with SSLs were age ≥ 40 [odds ratio (OR): 3.303; 95%CI: 1.607-6.790], male sex (OR: 2.032; 95%CI: 1.204-3.429), diabetes mellitus (OR: 2.721; 95%CI: 1.551-4.772), and hypertension (OR: 1.650, 95%CI: 1.045-2.605). The rate of BRAF mutations in SSLs was 35.5%.

CONCLUSION

The prevalence of SSLs was 4.2%. BRAF mutations were present in one-third of SSLs. Significant risk factors for SSLs included age ≥ 40, male sex, diabetes mellitus, and hypertension.

Third Asia-Pacific consensus recommendations on colorectal cancer screening and postpolypectomy surveillance

The Asia-Pacific region has the largest number of cases of colorectal cancer (CRC) and one of the highest levels of mortality due to this condition in the world. Since the publishing of two consensus recommendations in 2008 and 2015, significant advancements have been made in our knowledge of epidemiology, pathology and the natural history of the adenoma-carcinoma progression. Based on the most updated epidemiological and clinical studies in this region, considering literature from international studies, and adopting the modified Delphi process, the Asia-Pacific Working Group on Colorectal Cancer Screening has updated and revised their recommendations on (1) screening methods and preferred strategies; (2) age for starting and terminating screening for CRC; (3) screening for individuals with a family history of CRC or advanced adenoma; (4) surveillance for those with adenomas; (5) screening and surveillance for sessile serrated lesions and (6) quality assurance of screening programmes. Thirteen countries/regions in the Asia-Pacific region were represented in this exercise. International advisors from North America and Europe were invited to participate.

Post-polypectomy surveillance: the present and the future

An appropriate post-polypectomy surveillance program requires the effectiveness of reducing colorectal cancer and safety. In addition, the post-polypectomy surveillance program should consider the burden of limited medical resource capacity, cost-effectiveness, and patient adherence. In this sense, a risk-stratified surveillance program based on baseline colonoscopy results is ideal. Major international guidelines for post-polypectomy surveillance, such as those from the European Union and the United States, have recommended risk-stratified surveillance programs. Both guidelines have recently been updated to better differentiate between high- and low-risk individuals. In both updated guidelines, more individuals have been downgraded to lower-risk groups that require less frequent or no surveillance. Furthermore, increased attention has been paid to the surveillance of patients who undergo serrated polyp removal. Previous guidelines in Japan did not clearly outline the risk stratification in post-polypectomy surveillance. However, the new colonoscopy screening and surveillance guidelines presented by the Japan Gastroenterological Endoscopy Society include a risk-stratified post-polypectomy surveillance program. Further discussion and analysis of unresolved issues in this field, such as the optimal follow-up after the first surveillance, the upper age limit for surveillance, and the ideal method for improving adherence to surveillance guidelines, are warranted.

Risk of metachronous neoplastic lesions during post-polypectomy surveillance in individuals with advanced colorectal neoplasia at initial screening colonoscopy

BACKGROUND AND AIM

The evidence of associations between some types of advanced colorectal neoplasia (ACN) at baseline and the risk of metachronous neoplasia is inconsistent. This study aimed to elucidate the incidence of metachronous neoplasia during post-polypectomy surveillance in individuals with ACN at baseline and examine the risk factors for its high incidence.

METHODS

Data from individuals who underwent endoscopic resection for ACN and received surveillance colonoscopy were analyzed. Data from individuals with no neoplastic lesions at baseline were used as reference. The incidence of metachronous ACN and clinically significant neoplasia (ACN and nonadvanced adenomas sized ≥ 5 mm) were evaluated. Risk factors for the higher incidence of these lesions were examined in individuals with ACN at baseline.

RESULTS

During the median follow-up period of 61.8 months, metachronous ACN and nonadvanced adenomas sized ≥ 5 mm were detected in 9.6% and 32.4% of individuals with ACN at baseline (n = 136), respectively. The cumulative incidence of metachronous ACN and clinically significant neoplasia in individuals with ACN at baseline (3-year incidence: 5.5% and 16.9%, respectively) was higher than that in individuals with no neoplastic lesions at baseline (P < 0.01 for both). The presence of advanced histology at baseline, ≥ 5 neoplastic lesions at baseline, and family history of colorectal cancer were identified as risk factors for the higher incidence of clinically significant neoplasia.

CONCLUSIONS

The relatively high incidence of metachronous neoplasia in individuals with ACN at baseline was confirmed; careful surveillance is required for these individuals, particularly in those with the risk factors.