The Adenoma-carcinoma Sequence in Colorectal Neoplasia

Can circulating microRNAs predict colorectal cancer? Results from a nested case-control study of pre-diagnostic serum samples from two prospective biobanks

BACKGROUND

This study aimed to investigate the potential of circulating small RNAs (sRNAs) as predictive biomarkers for future colorectal cancer (CRC). The study analyzed serum samples from pre-diagnostic CRC patients in two prospective biobanks.

METHODS

Serum samples from 142 pre-diagnostic CRC patients, from the Finnish Maternity Cohort (FMC) and The HUNT Study (HUNT2), were subjected to small RNA sequencing. The study compared sRNA expression in CRC cases with controls, considering diverse sRNA classes.

RESULTS

Analysis revealed diverse miRNA expression patterns with notable variations in future metastatic cases. Specifically, miR-223-3p and miR-21-5p showed significant up-regulation in future metastatic cases in the FMC cohort. Consistent changes were observed across cohorts, with miR-584-5p, miR-30c-5p, miR-146a-5p, miR-10a-5p, and miR-1306-5p showing up-regulation in future metastatic cases.

CONCLUSIONS

The study identified potential serum miRNA biomarkers associated with metastatic CRC, though statistical significance varied. These findings contribute to the understanding of miRNA profiles in pre-diagnostic CRC patients, emphasizing the need for further exploration of non-invasive biomarkers in large prospective studies.

Gut-associated lymphoid tissue carcinoma analyzed using next-generation sequencing: A case report

Tumors related to the gut-associated lymphoid tissue (GALT) have been recently described. GALT carcinomas (GCs) have a characteristic appearance: macroscopically, they appear as a "dome-type" lesion, whereas microscopically, they show dilated cystic glands in the submucosa, differentiated adenocarcinoma without goblet cells, and stromal lymphocytes with germinal centers. However, their origin and pathogenesis remain controversial. Here, we present the case of a 54-year-old man that presented with a protruding lesion in the upper rectum during colonoscopy and had no family or past medical history. Low anterior resection was performed, and the tumor was diagnosed as GC based on its typical morphology. The tumor cells were negative for Mucin 2 and other mucins and CD10. p53 showed null-type. The tumor was associated with rich lymphocyte infiltration and germinal centers. Next-generation sequencing detected EGFR missense and TP53 nonsense mutations. Although GCs are known as conventional colorectal carcinomas that invade the submucosa, this case showed no neoplastic lesion in the mucosal epithelium in situ. Moreover, we detected EGFR and TP53 mutations (no pathogenic APC or KRAS mutations), which are not conventional adenoma-carcinoma mutations. Further studies are warranted to confirm whether GC is a sporadic carcinoma that invades the GALT submucosa.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Colorectal Cancer and Precursor Lesion Prevalence in Adults Younger Than 50 Years Without Symptoms

Importance

Incidence of colorectal cancer (CRC) is increasing among younger adults. However, data on precursor lesions in patients who are asymptomatic, especially those aged younger than 50 years, are lacking.

Objective

To analyze the prevalence and number needed to screen (NNS) for adenomas, advanced adenomas, and serrated lesions, as well as the incidence of CRC in patients older than age 20 years.

Design, Setting, and Participants

This cohort study was conducted among 296 170 patients who received a screening colonoscopy within a national screening colonoscopy registry from 2012 to 2018 in Austria, including 11 103 patients aged younger than 50 years. CRC incidence was analyzed using data from Statistic Austria from 1988 to 2018. Data were analyzed in September 2021.

Main Outcome and Measures

The prevalence of adenomas and other lesions and the incidence of CRC in individuals aged 20 years or older were assessed.

Results

Among 296 170 patients included in the study (median [IQR] age, 60 [54-68] years; 150 813 females [50.9%]), 11 103 patients (3.7%) were aged younger than 50 years and 285 067 patients (96.3%) were aged 50 years or older. Among patients younger than age 50 years, 1166 individuals (10.5%; NNS = 9) had adenomas and 389 individuals (3.9%; NNS = 26) had at least 1 advanced adenoma, while among those aged 50 years or older, 62 384 individuals (21.9%; NNS = 5) had adenomas and 19 680 individuals (6.9%; NNS = 15) had at least 1 advanced adenoma. Among 1128 males aged 40 to 44 years, 160 individuals (14.2%; NNS = 7) had at least 1 adenoma, and among 1398 females aged 40 to 44 years, 114 individuals (8.1%; NNS = 12) had at least 1 adenoma. The prevalence of adenomas for individuals aged 45 to 49 years vs 50 to 54 years was 490 of 2879 males (17.1%; NNS = 6) vs 8269 of 40 935 males (20.2%; NNS = 5) and 284 of 2792 females (10.2%; NNS = 10) vs 4997 of 40 303 females (12.4%; NNS = 8), respectively. Prevalence of adenomas changed from 61 of 498 individuals (12.4%) in 2008 to 150 of 1064 individuals (14.1%) in 2018 among those younger than 50 years and from 2646 of 12 166 individuals (21.8%) to 10 673 of 37 922 individuals (28.2%) among those aged 50 years and older. The prevalence of advanced adenomas changed from 20 individuals (4.0%) in 2008 to 55 individuals (5.2%) in 2018 in individuals younger than 50 years and from 888 individuals (7.3%) in 2008 to 2578 individuals (6.8%) in 2018 among those aged 50 years and older. Among individuals younger than age 50 years, CRC incidence per 100 000 individuals changed from 9.1 incidents in 1988 to 10.2 incidents in 2018 among males (average annual percentage change [AAPC], 0.5%; 95% CI, 0.1% to 1.0%) and from 9.7 incidents in 1988 to 7.7 incidents in 2018 among females, with a nonsignificant AAPC (-0.2%; 95% CI, -0.7% to 0.3%). Among individuals aged 50 years or older, CRC incidence per 100 000 individuals changed from 168 incidents in 1988 to 97 incidents in 2018 among females (AAPC, -1.8%; 95% CI, -1.9% to -1.6%), and 217 incidents in 1988 to 143 incidents in 2018 among males (AAPC, -1.2%; 95% CI, -1.3% to -1.1%).

Conclusion

In this study, CRC incidence decreased after 1988 in Austria among individuals older than 50 years, while among patients younger than 50 years, incidence increased among males but decreased among females. Prevalence of adenomas increased in all age groups, while advanced adenoma prevalence increased among patients younger than 50 years but decreased in patients aged 50 years and older.

Neoadjuvant botensilimab plus balstilimab response pattern in locally advanced mismatch repair proficient colorectal cancer

In patients with locally advanced cancer without distant metastases, the neoadjuvant setting presents a platform to evaluate new drugs. For mismatch repair proficient/microsatellite stable (pMMR/MSS) colon and rectal cancer, immunotherapy has shown limited efficacy. Herein, we report exceptional responses observed with neoadjuvant botensilimab (BOT), an Fc-enhanced next-generation anti-CTLA-4 antibody, alongside balstilimab (BAL; an anti-PD-1 antibody) in two patients with pMMR/MSS colon and rectal cancer. The histological pattern of rapid immune response observed ("inside-out" (serosa-to-mucosa) tumor regression) has not been described previously in this setting. Spatial biology analyses (RareCyte Inc.) reveal mechanisms of actions of BOT, a novel innate-adaptive immune activator. These observations have downstream implications for clinical trial designs using neoadjuvant immunotherapy and potentially sparing patients chemotherapy.

The incremental yield of adenoma detection with I-Scan versus high-definition white light colonoscopy-a systematic review and meta-analysis of randomized studies

INTRODUCTION

The incremental yield of I-Scan virtual chromoendoscopy compared to high-definition white light endoscopy (HD-WLE) in detection of colorectal adenomas has not been thoroughly elucidated.

METHODS

A systematic search from inception to April 2023 was conducted to identify randomized controlled trials (RCTs) comparing I-Scan to HD-WLE for detection of adenomas. A random effects model was used to compute risk difference (RD) with corresponding 95% confidence intervals in adenoma detection rate (ADR). Influence analysis was done to assess robustness of findings. The number needed to diagnose was computed. Heterogeneity was assessed using the I2 statistic and explored further by subgroup analyses defined a priori. Certainty in effect estimates was assessed using the GRADE approach.

RESULTS

We identified four studies (I-Scan n = 730, HD-WLE n = 765). I-Scan increased adenoma detection by 9% (risk difference (RD), 0.09; 0.04, 0.14; I2 02%; certainty, low). Influence analysis revealed that the gain in yield remained statistically significant with exclusion of all but one study. The number needed to capture one additional adenomatous polyp with I-Scan use was 11.2. I-Scan 1 use was associated with a statistically significant gain in ADR, whereas no significant difference in ADR was noted with I-Scan use on subgroup analysis.

DISCUSSION

In conclusion, I-Scan increases the yield of adenoma detection by 9% compared to HD-WLE, with low certainty in the estimate of this effect. Data on the gain in yield of detecting large polyps, sessile serrated lesions, and on the impact of formally training endoscopists and trainees in I-Scan use and similar technology on adenoma detection rate are needed.

Curriculum for training in endoscopic mucosal resection in the colon: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Endoscopic mucosal resection (EMR) is the standard of care for the complete removal of large (≥ 10 mm) nonpedunculated colorectal polyps (LNPCPs). Increased detection of LNPCPs owing to screening colonoscopy, plus high observed rates of incomplete resection and need for surgery call for a standardized approach to training in EMR. 1 : Trainees in EMR should have achieved basic competence in diagnostic colonoscopy, < 10-mm polypectomy, pedunculated polypectomy, and common methods of gastrointestinal endoscopic hemostasis. The role of formal training courses is emphasized. Training may then commence in vivo under the direct supervision of a trainer. 2 : Endoscopy units training endoscopists in EMR should have specific processes in place to support and facilitate training. 3: A trained EMR practitioner should have mastered theoretical knowledge including how to assess an LNPCP for risk of submucosal invasion, how to interpret the potential difficulty of a particular EMR procedure, how to decide whether to remove a particular LNPCP en bloc or piecemeal, whether the risks of electrosurgical energy can be avoided for a particular LNPCP, the different devices required for EMR, management of adverse events, and interpretation of reports provided by histopathologists. 4: Trained EMR practitioners should be familiar with the patient consent process for EMR. 5: The development of endoscopic non-technical skills (ENTS) and team interaction are important for trainees in EMR. 6: Differences in recommended technique exist between EMR performed with and without electrosurgical energy. Common to both is a standardized technique based upon dynamic injection, controlled and precise snare placement, safety checks prior to the application of tissue transection (cold snare) or electrosurgical energy (hot snare), and interpretation of the post-EMR resection defect. 7: A trained EMR practitioner must be able to manage adverse events associated with EMR including intraprocedural bleeding and perforation, and post-procedural bleeding. Delayed perforation should be avoided by correct interpretation of the post-EMR defect and treatment of deep mural injury. 8: A trained EMR practitioner must be able to communicate EMR procedural findings to patients and provide them with a plan in case of adverse events after discharge and a follow-up plan. 9: A trained EMR practitioner must be able to detect and interrogate a post-endoscopic resection scar for residual or recurrent adenoma and apply treatment if necessary. 10: Prior to independent practice, a minimum of 30 EMR procedures should be performed, culminating in a trainer-guided assessment of competency using a validated assessment tool, taking account of procedural difficulty (e. g. using the SMSA polyp score). 11: Trained practitioners should log their key performance indicators (KPIs) of polypectomy during independent practice. A guide for target KPIs is provided in this document.

Integrated Decision-Making in the Treatment of Colon-Rectal Cancer: The Case of KRAS-Mutated Tumors

In recent years, precision medicine has taken an increasing place in various branches of medical oncology, including colorectal cancer. Among the potentially relevant mutations for this cancer is the KRAS mutation, initially defined as "untargetable"; today, we see the birth of new molecules that target one of the variants of the KRAS mutation, KRAS G12C, having a significant impact on the therapeutic options for other malignancies, such as metastatic lung cancer. This fundamental step forward has stimulated scientific research on other potential targets of KRAS, both indirect and direct, and combination treatments aiming to overcome the mechanisms of resistance to these drugs that decrease in efficacy in colorectal cancer. What was once a negative predictive marker of response to anti-EGFR drugs today has become a potential target for targeted treatments. In turn, the prognostic role of the mutation has become extremely interesting, making it a potentially useful element in therapeutic decision-making, not only regarding oncological treatments but also in a more complex and complete manner within a global vision of the patient, involving other figures on the multidisciplinary team, such as surgeons, radiotherapists, and interventional radiologists.

Two intertwined compartments coexisting in sporadic conventional colon adenomas

Sporadic conventional colon adenomas are microscopically built of 2 intertwined compartments: one on top, harboring the dysplastic tissue that defines their histo-biomolecular attributes, and the other below, composed of non-dysplastic crypts with corrupted shapes (CCS). The CCS of 306 colon adenomas revealed asymmetric, haphazardly-distributed proliferating cell-domains (PC). In contrast, the PC-domains in normal controls were symmetric, being limited to the lower thirds of the crypts. In 28% out of 501 sporadic conventional adenomas, foci of p53-upregulated dysplastic tissue were found. The CCS in 30% of 108 sporadic adenomas showed p53-upregulated single cells, suggesting mounting somatic mutations. No p53-upregulated cells were found in the crypts of controls. In polypoid adenomas, the mucosa of the stalk without dysplastic tissue on top disclosed CCS with asymmetrical PC-domains and single p53-upregulated cells. The latter observations suggested that CCS had developed prior to and not after the growth of the dysplastic tissue on top. CCS were also found below colon adenomas in carcinogen-treated rats. It is concluded that the 2 intertwined histo-biological compartments of sporadic conventional colon adenomas are probably interdependent components. These findings may open new directions aimed to uncover the link between the normal colonic mucosa and the histogenesis of, conventional adenomas.

Precision Medicine for CRC Patients in the Veteran Population: State-of-the-Art, Challenges and Research Directions

Colorectal cancer (CRC) accounts for ~9% of all cancers in the Veteran population, a fact which has focused a great deal of the attention of the VA's research and development efforts. A field-based meeting of CRC experts was convened to discuss both challenges and opportunities in precision medicine for CRC. This group, designated as the VA Colorectal Cancer Cell-genomics Consortium (VA4C), discussed advances in CRC biology, biomarkers, and imaging for early detection and prevention. There was also a discussion of precision treatment involving fluorescence-guided surgery, targeted chemotherapies and immunotherapies, and personalized cancer treatment approaches. The overarching goal was to identify modalities that might ultimately lead to personalized cancer diagnosis and treatment. This review summarizes the findings of this VA field-based meeting, in which much of the current knowledge on CRC prescreening and treatment was discussed. It was concluded that there is a need and an opportunity to identify new targets for both the prevention of CRC and the development of effective therapies for advanced disease. Also, developing methods integrating genomic testing with tumoroid-based clinical drug response might lead to more accurate diagnosis and prognostication and more effective personalized treatment of CRC.

The third pathway of colorectal carcinogenesis

Aims

The majority of the colorectal carcinomas (CRC) arise in a vast mucosal area built with columnar cells and mucus-producing goblet cells. These carcinomas evolve via the conventional (tubular/villous) adenoma–carcinoma pathway, or the serrated adenoma–carcinoma pathway. Much less frequently CRC arise in the gut-associated lymphoid tissue (GALT) mucosal domain via the third pathway of colorectal carcinogenesis.

Methods

All publications on human colorectal GALT carcinomas in the literature were reviewed.

Results

Only 23 GALT-carcinomas found in 20 patients are in record. The GALT carcinomas were detected at surveillance colonoscopic biopsy in 11 patients (four had ulcerative colitis, two were members of a Lynch syndrome family, two of a CRC family, one had familial adenomatous polyposis (FAP), one prior colon adenomas and one a submucosal tumour), or at diagnostic colonoscopic biopsy in the remaining nine patients (three had rectal bleedings, two abdominal pains, one diverticular disease and one protracted constipation. In three, no ground disease or symptoms were provided). In six of the 23 GALT carcinomas, the luminal surface showed tumour cells, ulcerations or no descriptions were given. Ten (66.7%) of the remaining 15 GALT carcinomas showed on top, adenomas (n=8) or high-grade dysplasia (n=2).

Conclusions

The low frequency of GALT carcinomas might be explained by the fact that the colorectal mucosal areas occupied by GALT domains are minute. The finding that two-thirds of the 15 remaining GALT carcinomas (vide supra) were covered by high-grade dysplasia or by conventional adenomas strongly suggest that conventional non-invasive neoplasias might have preceded the majority of the GALT carcinomas in record.

Traditional serrated adenomas of the upper digestive tract

For many years, it was generally accepted that the vast majority of the colorectal carcinomas (CRCs) evolved from conventional adenomas, via the adenoma–carcinoma sequence. More recently, serrated colorectal polyps (hyperplastic polyps, sessile serrated polyps and traditional serrated adenomas (TSAs)) have emerged as an alternative pathway of colorectal carcinogenesis. It has been estimated that about 30% of the CRC progress via the serrated pathway. Recently, TSAs were also detected in the upper digestive tract. In this work, we review the literature on TSA in the oesophagus, the stomach, the duodenum, the pancreatic main duct and the gallbladder. The review indicated that 53.4% (n=39) out of the 73 TSA of the upper digestive tract now in record showed a simultaneously growing invasive carcinoma. As a corollary, TSAs of the upper digestive tract are aggressive adenomas that should be radically excised, either endoscopically or surgically, to rule out the possibility of a synchronously growing invasive adenocarcinoma or to prevent cancer progression. The present findings substantiate a TSA pathway of carcinogenesis in the upper digestive tract.

Accuracy of colorectal polyp self-reports: findings from the colon cancer family registry

INTRODUCTION

Colorectal adenomas and other types of polyps are commonly used as end points or risk factors in epidemiologic studies. However, it is not known how accurately patients are able to self-report the presence or absence of adenomas following colonoscopy.

METHODS

Participants in the Colon Cancer Family Registry provided self-reports of recent colorectal cancer (CRC) screening activity, and whether or not they had ever been told they had a polyp. Positive and negative predictive values for polyp self-report were calculated by comparing medical records with self-reports from 488 participants.

RESULTS

The positive predictive value for self-reported polyp was 80.9%, and the negative predictive value was 85.8%. The predictive values did not differ by age group or sex, but participants with a previous diagnosis of CRC had a lower negative predictive value (76.2%) than participants with no personal history of CRC (89.0%; P = 0.04).

CONCLUSIONS

Predictive values for self-reports of polyps are fairly high, but researchers needing accurate polyp data should obtain medical record confirmation. Pursuing medical records on only those participants self-reporting a polyp could result in an underestimation of the polyp prevalence in a study population.