Rising incidence of colorectal cancer in individuals younger than 50 years and increasing mortality from rectosigmoid cancer in England

How have US colorectal cancer mortality trends changed in the past 20 years?

In the last two decades, colorectal cancer (CRC) mortality has been decreasing in the United States. However, the mortality trends for the different subtypes of CRC, including different sides of colon, rectosigmoid, and rectal cancer remain unclear. We analyzed the mortality trends of different subtypes of CRC based on Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research data from 1999 to 2020. We calculated age-adjusted mortality rates (AAMR) per 100,000 individuals and examined the trends over time by estimating the average annual percent change (AAPC) using the Joinpoint Regression Program. Our study shows that the overall CRC rates decreased significantly from 26.42 to 15.98 per 100,000 individuals, with an AAPC of -2.41. However, the AAMR of rectosigmoid cancer increased significantly from 0.82 to 1.08 per 100,000 individuals, with the AAPC of +1.10. Men and Black individuals had the highest AAMRs respectively (23.90 vs. 26.93 per 100,000 individuals). The overall AAMR of CRC decreased for those aged ≥50 years but increased significantly from 1.02 to 1.58 per 100,000 individuals for those aged 15-49 years, with an AAPC of +0.75. Rural populations had a higher AAMR than the urban populations (22.40 vs. 19.60 per 100,000 individuals). Although overall CRC mortality declined, rising trends in young-onset CRC and rectosigmoid cancer warrant attention. Disparities persist in terms of sex, race, and geographic region, and urbanization level, emphasizing the need for targeted public health measures.

Temporal trends in age- and stage-specific incidence of colorectal adenocarcinomas in Germany

BACKGROUND

A national colorectal cancer (CRC) screening programme was launched in 2002 in Germany. A comprehensive evaluation of the programme effectiveness using real-world data is still lacking. In addition, there are regional reports on increasing colorectal cancer incidence in younger populations. Therefore, we aimed to describe and compare the overall, age- and stage-specific incidence trends for colorectal, colon and rectal cancer.

METHODS

We used data from seven population-based cancer registries in Germany. We report absolute and relative changes in incidence rates between the early screening phase (2003-2005) and the most recent time period available (2015-2017), as well as annual percent changes. We analysed incidences according to tumour site (colorectum, colon, and rectum) and to six age groups (young adults: 15-34, 35-39, 40-49, screening-entitled/older adults: 50-54, 55-69 and 70 + years old).

RESULTS

In our sample of 271,011 colorectal adenocarcinomas, about two-thirds were located in the colon and 95% of them occurred in the age group 50+ (50-54: 5%, 55-69: 32.8%, 70+: 57.2%). For the time period 2003-2005 the age-specific incidence rates of individuals in the age group 55-69 were about 76/100,00 for colon and 54/100,000 for rectal cancer (age group 70 + colon: 179/100,000; rectum: 84/100,000). The incidence rates in young adults were less than 13% of that of individuals in the age group 55-69 (< 5% of individuals aged 70+; <33% of individuals aged 50-54). Over time, incidence decreased in individuals at the age of 55+, for all subsites considered as well as for early and late stage cancers (with few exceptions), while incidence of young adult CRC (both early and late stage) increased steepest in the youngest age groups. For late stage rectal cancer, a shift was observed in all age groups from UICC stage IV to stage III being the most frequent stage.

CONCLUSIONS

Six years after the introduction of the national colonoscopy screening program, late stage CRC incidence began to decline substantially in the screening-eligible age groups (55-69, 70+). It is likely that this decline and the increase in early stage CRC observed in younger age groups can be attributed to the program. Long lasting public awareness campaigns for CRC screening might have led to opportunistic screening in younger adults. Whether these benefits outweigh the possible harm of screening in younger age groups remains unclear.

The Cancer Genome Atlas (TCGA) based m6A methylation-related genes predict prognosis in rectosigmoid cancer

N6-methyladenosine (m6A) methylation plays an important role in the occurrence and development of tumors. This study aimed to explore the effects of m6A methylation regulatory genes on rectosigmoid cancer (RSC). RNA-seq data and related clinical information in The Cancer Genome Atlas database were analyzed. The Wilcoxon test was used to analyze the different expression levels of m6A methylation regulatory genes between the tumor and normal samples. Least absolute shrinkage and selection operator Cox regression analysis was used to construct a risk prognosis model between the m6A methylation regulatory genes and RSC. The median risk score was used to classify RSC patients into high and low-risk groups. Kaplan-Meier survival analysis and receiver operating characteristic curves were used to evaluate the sensitivity and specificity of the prediction model. The expression of m6A methylation regulation genes was different between the tumor and normal samples, 6 genes were overexpressed in tumor and 2 genes were down-regulated. Four m6A methylation regulatory genes, YTHDF3, KIAA1429, ALKBH5 and METTL3, were screened by least absolute shrinkage and selection operator Cox regression analysis. The overall survival of high-risk group was significantly lower than that of low-risk group (P = 4.681 × 10-4). The area under the curve value in the receiver operating characteristic curve was 0.935, indicating that the prediction model was effective. Univariate and multivariate Cox regression were used to test the effectiveness of the model. m6A methylation regulators YTHDF3, KIAA1429, ALKBH5, and METTL3 can be used to construct predictive models to predict overall survival in different clinical subgroups of RSC patients.

Implementation of optical diagnosis with a "resect and discard" strategy in clinical practice: DISCARD3 study

BACKGROUND AND AIMS

Optical diagnosis (OD) of polyps can be performed with advanced endoscopic imaging. For high-confidence diagnoses, a "resect and discard" strategy could offer significant histopathology time and cost savings. The implementation threshold is a ≥90% OD-histology surveillance interval concordance. Here we assessed the OD learning curve and feasibility of a resect and discard strategy for ≤5-mm and <10-mm polyps in a bowel cancer screening setting.

METHODS

In this prospective feasibility study, 8 bowel cancer screening endoscopists completed a validated OD training module and performed procedures. All <10-mm consecutive polyps had white-light and narrow-band images taken and were given high- or low-confidence diagnoses until 120 high-confidence ≤5-mm polyp diagnoses had been performed. All polyps had standard histology. High-confidence OD errors underwent root-cause analysis. Histology and OD-derived surveillance intervals were calculated.

RESULTS

Of 565 invited patients, 525 patients were included. A total of 1560 <10-mm polyps underwent OD and were resected and retrieved (1329 ≤5 mm and 231 6-9 mm). There were no <10-mm polyp cancers. High-confidence OD was accurate in 81.5% of ≤5-mm and 92.8% of 6-9-mm polyps. Sensitivity for OD of a ≤5-mm adenoma was 93.0% with a positive predictive value of 90.8%. OD-histology surveillance interval concordance for ≤5-mm OD was 91.3% (209/229) for U.S. Multi-Society Task Force, 98.3% (225/229) for European Society of Gastrointestinal Endoscopy, and 98.7% (226/229) for British Society of Gastroenterology guidelines, respectively.

CONCLUSIONS

A resect and discard strategy for high-confidence ≤5-mm polyp OD in a group of bowel cancer screening colonoscopists is feasible and safe, with performance exceeding the 90% surveillance interval concordance required for implementation in clinical practice. (Clinical trial registration number: NCT04710693.).

MicroRNA-let-7 Targets HMGA2 to Regulate the Proliferation, Migration, and Invasion of Colon Cancer Cell HCT116

Objective

To investigate the effect of microRNA-let-7 (miR-let-7) on the proliferation, migration, and invasion of colon cancer cell HCT116 in vitro and its regulatory mechanism on downstream HMGA2.

Methods

It was planned to synthesize miR-let-7 overexpression (mimics) and interference expression (inhibitor) and transiently transfect colon cancer cell HCT116, detect the expression levels of miR-let-7 and HMGA2 in the cells after transfection and the targeted regulation effect of miR-let-7 on HMGA2, then detect the effect of upregulation/downregulation of miR-let-7 on HMGA2, and detect the proliferation, migration, and invasion of HCT116 cells.

Results

The expression of miR-let-7 was downregulated, and the expression of HMGA2 was upregulated in HCT116. The expression of miR-let-7 increased significantly after HCT116 was transfected with miR-let-7 mimics. The expression of miR-let-7 decreased significantly after HCT116 was transfected with miR-let-7 inhibitor. The bioinformatics websites predicted that miR-let-7 has a binding site with HMGA2, and the dual-luciferase reporter gene experiment detected that miR-let-7 has a targeting relationship with HMGA2. The expression of HMGA2 decreased after HCT116 was transfected with miR-let-7 mimics; the expression of HMGA2 increased after HCT116 was transfected with miR-let-7 inhibitor. After upregulating miR-let-7, the proliferation, migration, and invasion ability of HCT116 was weakened. After miR-let-7 was inhibited, the proliferation, migration, and invasion ability of HCT116 was enhanced.

Conclusion

Abnormal expression of miR-let-7 is an important factor affecting the proliferation, migration, and invasion of HCT116 cells, and it can promote or inhibit the biological behavior of cancer cells by targeting the expression of HMGA2. This study provides ideas for the drug development of new gene targets.