Post-colonoscopy colorectal cancer: the key role of molecular pathological epidemiology

Most large colorectal polyps missed by gastroenterology fellows at colonoscopy are sessile serrated lesions

Background and study aims  Data on adenoma and sessile serrated lesion (SSL) miss rates for gastroenterology fellows during colonoscopy are limited. We aimed to describe the miss rate of fellows based on a second examination by a colonoscopist with a high rate of detection. Patients and methods  Second- and third-year gastroenterology fellows at a single, tertiary center performed initial examinations. A single experienced attending doctor then performed a complete examination of the colon. We recorded the size and pathology of all lesions found at both examinations and calculated the adenoma and SSL miss rates for fellows. Results  Ten trainees performed 100 examinations. Miss rates for conventional adenomas and SSLs were 30.5 % and 85.7 %, respectively. Among pre-cancerous polyps ≥ 10 mm, 10 of 14 lesions missed were SSLs. Conclusions  While conventional adenoma detection skills of gastroenterology fellows are acceptable, SSL detection is poor.

Interval cancer after colonoscopy in the Austrian National Screening Programme: influence of physician and patient factors

OBJECTIVE

Postscreening colorectal cancer (PSCRC) after screening colonoscopy is associated with endoscopists' performance and characteristics of resected lesions. Prior studies have shown that adenoma detection rate (ADR) is a decisive factor for PSCRC, but correlations with other parameters need further analysis and ADR may change over time.

DESIGN

Cohort study including individuals undergoing screening colonoscopy between 1/2008 and 12/2019 performed by physicians participating in a quality assurance programme in Austria. Data were linked with hospitalisation data for the diagnosis of PSCRC (defined as CRC diagnosis >6 months after colonoscopy). ADR was defined dynamically in relation to the time point of subsequent colonoscopies; high-risk groups of patients were those with an adenoma ≥10 mm, or with high-grade dysplasia, or villous or tubulovillous histology, or a serrated lesion ≥10 mm or with dysplasia, or colonoscopies with ≥3 lesions. Main outcome was PSCRC for each risk group (negative colonoscopy, hyperplastic polyps, low-risk and high-risk group of patients) after colonoscopy by endoscopists with an ADR <20% compared with endoscopists with an ADR ≥20%.

RESULTS

352 685 individuals were included in the study (51.0% women, median age 60 years) of which 10.5% were classified as high-risk group. During a median follow-up of 55.4 months, 241 (0.06%) PSCRC were identified; of 387 participating physicians, 19.6% had at least one PSCRC (8.4% two or more). While higher endoscopist ADR decreased PSCRC incidence (HR per 1% increase 0.97, 95% CI 0.95 to 0.98), affiliation to the high-risk group of patients was also associated with higher PSCRC incidence (HR 3.27, 95% CI 2.36 to 4.00). Similar correlations were seen with regards to high-risk, and advanced adenomas. The risk for PSCRC was significantly higher after colonoscopy by an endoscopist with an ADR <20% as compared with an endoscopist with an ADR ≥20% in patients after negative colonoscopy (HR 2.01, 95% CI 1.35 to 3.0, p<0.001) and for the high-risk group of patients (HR 2.51, 95% CI 1.49 to 4.22, p<0.001).

CONCLUSION

A dynamic calculation of the ADR takes into account changes over time but confirms the correlation of ADR and interval cancer. Both lesion characteristics and endoscopists ADR may play a similar role for the risk of PSCRC. This should be considered in deciding about appropriate surveillance intervals in the future.

miRNA-708 functions as a tumor suppressor in colorectal cancer by targeting ZEB1 through Akt/mTOR signaling pathway

BACKGROUND

Colon cancer, or colorectal cancer (CRC), is a type of cancer that develops from large bowel. Previous data has demonstrated that microRNAs (miRNAs) may be involved in the formation and progression of CRC. The deregulation of miR-708 has been identified in multiple types of cancer. However, to the best of our knowledge, there are no data concerning the expression and role of miR-708 in CRC.

METHODS

In this study, RT-PCR and Flow Cytometry were used to examine the expression and role of miR-708 and ZEB1 in proliferation and apoptosis. Transwell was used to examine the role of miR-708 and ZEB1 in invasion and migration. Western blot and qRT-PCR were conducted to determine the alteration of protein and miR-708 levels, respectively.

RESULTS

MiR-708 was significantly downregulated in CRC tissues and cell lines. The restoration of the expression of miR-708 suppressed cell proliferation, induced apoptosis, and reduced metastasis in CRC in vitro. Additionally, bioinformatics analysis predicted ZEB1 as a novel target gene of miR-708. Furthermore, ZEB1 was upregulated in CRC, which was negatively correlated with miR-708 expression. Further studies showed that the overexpression of miR-708 and silence of ZEB1 inhibited stage of CRC via inhibiting AKT/mTOR signaling pathway in CRC cells.

CONCLUSION

Taken together, these results indicate that miR-708 plays an important role in suppressing the development of CRC by directly targeting ZEB1 through AKT/mTOR signaling pathway, suggesting that miR-708 is a novel, effective therapeutic target for treating patients with CRC.

Interval colorectal cancer: a challenging field in colorectal cancer

Accumulated evidence has shown that colonoscopy may not be a perfect tool in screening and reducing the incidence of the colorectal cancer (CRC), because interval CRC (I-CRC), a specific subgroup of CRCs, has been challenging the traditional detection technology in recent years. I-CRC is accounting for an increasing proportion in CRCs. However, the effective procedures to prevent and supervise I-CRC need to be explored. In this review, we summarized the incidence, causes, risk factors, characteristics and management of I-CRC. It would promote the awareness of the special value in the education and training for the gastroenterologists, which plays an important role in conquering CRC.