Endoscopic management of Lynch syndrome and of familial risk of colorectal cancer: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

Quality of endoscopic surveillance of Lynch syndrome patients in a Swedish cohort

Background and study aims Risk factors for colorectal cancer (CRC) in Lynch syndrome (LS) include sex, age, smoking, high body mass index (BMI), surveillance interval length, and risk genotype. The Boston Bowel Preparation Scale (BBPS) produces a standardized bowel cleanliness rating. A low BBPS score might be a risk factor for missed early lesions. The aim of this study was to investigate the correlation between BBPS score and adenoma detection (with known risk factors for CRC) and surveillance interval with CRC detection in LS patients. Methods A retrospective cohort study including 366 LS patients with 1,887 colonoscopies under surveillance in Stockholm, Sweden from 1989 to 2021 was conducted. Associations were tested using linear and logistic regression. Results We found no association between BBPS score and number of adenomas detected. A low BBPS score was found to be associated with older age (regression coefficient (coeff) -0.015; 95% confidence interval [CI] -0.026 to -0.004; P = 0.007) and obesity (coeff = -0.48; 95% CI: -0.89 to -0.062; P = 0.024). A higher number of detected adenomas was associated with older age (coeff = 0.008; 95% CI 0.004 to 0.012; P < 0.001), male sex (coeff = 0.097; 95% CI 0.008 to 0.19; P = 0.033) and CRC (coeff = 0.28; 95% CI 0.061 to 0.50; P = 0.012). Surveillance interval length was not significant in CRC detection. Conclusions Bowel cleanliness was not associated with adenoma detection and was less likely achieved in patients who were older and had higher BMI. Adenoma detection was associated with older age and male sex. The results indicate the need for better adherence to guidelines and attention to older age groups, men, and patients with obesity.

Current management of familial adenomatous polyposis

INTRODUCTION

APC-associated polyposis is a rare hereditary disorder characterized by the development of multiple adenomas in the digestive tract. Individuals with APC-associated polyposis need to be managed by specialized multidisciplinary teams in dedicated centers.

AREAS COVERED

The study aimed to review the literature on Familial adenomatous polyposis (FAP) to provide an update on diagnostic and surgical management while focusing on strategies to minimize the risk of desmoid-type fibromatosis, cancer in anorectal remnant, and postoperative complications. FAP individuals require a comprehensive approach that includes diagnosis, surveillance, preventive surgery, and addressing specific extracolonic concerns such as duodenal and desmoid tumors. Management should be personalized considering all factors: genotype, phenotype, and personal needs. Total colectomy and ileo-rectal anastomosis have been shown to yield superior QoL results when compared to Restorative Procto colectomy and ileopouch-anal anastomosis with acceptable oncological risk of developing cancer in the rectal stump if patients rigorously adhere to lifelong endoscopic surveillance. Additionally, a low-inflammatory diet may prevent adenomas and cancer by modulating systemic and tissue inflammatory indices.

EXPERT OPINION

FAP management requires a multidisciplinary and personalized approach. Integrating genetic advances, innovative surveillance techniques, and emerging therapeutic modalities will contribute to improving outcomes and quality of life for FAP individuals.

Emerge of colorectal cancer in Lynch syndrome despite colonoscopy surveillance: A challenge of hide and seek

Even with colonoscopy surveillance, Lynch syndromes (LS) carriers still develop colorectal cancer (CRC). The cumulative incidence of CRCs under colonoscopy surveillance varies depending on the affected mismatch repair (MMR) gene. However, the precise mechanisms driving these epidemiological patterns remain incompletely understood. In recent years, several potential mechanisms explaining the occurrence of CRCs during colonoscopy surveillance have been proposed in individuals with and without LS. These encompass biological factors like concealed/accelerated carcinogenesis through a bypassed adenoma stage and accelerated progression from adenomas. Alongside these, various colonoscopy-related factors may contribute to formation of CRCs under colonoscopy surveillance, like missed yet detectable (pre)cancerous lesions, detected yet incompletely removed (pre)cancerous lesions, and colonoscopy-induced carcinogenesis due to tumor cell reimplantation. In this comprehensive literature update, we reviewed these potential factors and evaluated their relevance to each MMR group in an attempt to raise further awareness and stimulate research regarding this conflicting phenomenon.

The experience of receiving a letter from a cancer genetics clinic about risk for hereditary cancer

Direct contact may be an option for supporting disclosure in families with hereditary cancer risk. In this qualitative interview study, we explored how healthy at-risk relatives experience receiving a letter with information about hereditary cancer directly from healthcare rather than via a relative. The study is part of an ongoing multicentre randomised clinical trial in Sweden that evaluates the effectiveness of direct letters from cancer genetics clinics to at-risk relatives. After conducting semi-structured interviews with 14 relatives who had received a letter and contacted the clinic, we analysed the data using thematic analysis. The relatives had different levels of prior knowledge about the hereditary cancer assessment. Many had been notified by family that a letter was coming but some had not. Overall, these participants believed healthcare-mediated disclosure could complement family-mediated disclosure. They expressed that the letter and the message raised concerns and a need for counselling, and they wanted healthcare to be accessible and informed when making contact. The participants found the message easier to cope with when they had been notified by a family member beforehand, with a general attitude that notifying relatives was the appropriate step to take. They thought healthcare should help patients with the disclosure process but also guard the right of at-risk relatives to be informed. The findings support a direct approach from healthcare as a possible complement to an established model of family-mediated risk disclosure, but implementation must be made within existing frameworks of good practice for genetic counselling.

In vitro study of radiosensitivity in colorectal cancer cell lines associated with Lynch syndrome

Introduction

Lynch syndrome patients have an inherited predisposition to cancer due to a deficiency in DNA mismatch repair (MMR) genes which could lead to a higher risk of developing cancer if exposed to ionizing radiation. This pilot study aims to reveal the association between MMR deficiency and radiosensitivity at both a CT relevant low dose (20 mGy) and a therapeutic higher dose (2 Gy).

Methods

Human colorectal cancer cell lines with (dMMR) or without MMR deficiency (pMMR) were analyzed before and after exposure to radiation using cellular and cytogenetic analyses i.e., clonogenic assay to determine cell reproductive death; sister chromatid exchange (SCE) assay to detect the exchange of DNA between sister chromatids; γH2AX assay to analyze DNA damage repair; and apoptosis analysis to compare cell death response. The advantages and limitations of these assays were assessed in vitro, and their applicability and feasibility investigated for their potential to be used for further studies using clinical samples.

Results

Results from the clonogenic assay indicated that the pMMR cell line (HT29) was significantly more radio-resistant than the dMMR cell lines (HCT116, SW48, and LoVo) after 2 Gy X-irradiation. Both cell type and radiation dose had a significant effect on the yield of SCEs/chromosome. When the yield of SCEs/chromosome for the irradiated samples (2 Gy) was normalized against the controls, no significant difference was observed between the cell lines. For the γH2AX assay, 0, 20 mGy and 2 Gy were examined at post-exposure time points of 30 min (min), 4 and 24 h (h). Statistical analysis revealed that HT29 was only significantly more radio-resistant than the MLH1-deficient cells lines, but not the MSH2-deficient cell line. Apoptosis analysis (4 Gy) revealed that HT29 was significantly more radio-resistant than HCT116 albeit with very few apoptotic cells observed.

Discussion

Overall, this study showed radio-resistance of the MMR proficient cell line in some assays, but not in the others. All methods used within this study have been validated; however, due to the limitations associated with cancer cell lines, the next step will be to use these assays in clinical samples in an effort to understand the biological and mechanistic effects of radiation in Lynch patients as well as the health implications.

Surveillance of the small-bowel by capsule endoscopy in Lynch syndrome - A systematic review with meta-analysis

BACKGROUND & AIMS

The role of small-bowel (SB) cancer surveillance by capsule endoscopy (CE) in Lynch syndrome (LS) patients has been investigated in recent years, with contradicting results. This meta-analysis evaluates the diagnostic yield (DY) of CE as a screening tool in asymptomatic LS patients.

METHODS

A systematic literature search was performed for all studies reporting the results of SB cancer screening in patients with LS. The primary outcome was the evaluation of the DY of CE in this setting for consecutive screening rounds.

RESULTS

Five studies comprising 428 patients and CE 677 procedures were included for data extraction and statistical analysis. The estimated pooled DY for CE-identified pathological findings was 8% in the first screening round and 6% in the second. Limiting the analysis to histologically-confirmed pathological findings, the pooled DY of second-round screening dropped to 0%. The included studies showed a significantly different prevalence of pathogenic variants in mismatch repair (path_MMR) genes, which underlie different cumulative incidences of extracolonic cancers.

CONCLUSIONS

SB surveillance by CE with a 2-year interval in asymptomatic LS individuals does not appear to be an effective screening strategy. Confirmatory prospective studies in this context are needed, considering the different cumulative incidence of SB tumors according to underlying path_MMR defects.

Gastric and duodenal cancer in individuals with Lynch syndrome: a nationwide cohort study

Background

Lynch syndrome increases the risk of gastric cancer (GC) and duodenal cancer (DC), particularly in individuals with MLH1 and MSH2 pathogenic variants (PVs). To provide further insight into whether, and from what age, esophagogastroduodenoscopy (EGD) surveillance may be beneficial, we evaluated the cumulative incidence and tumour characteristics of GC and DC in a large nationwide cohort of Dutch individuals with LS.

Methods

For this retrospective nationwide cohort study, clinical data of individuals with LS registered at the Dutch Hereditary Cancer Registry were matched with pathology reports filed by the Dutch Pathology registry. All individuals registered between Jan 1, 1989 and Dec 31, 2021 with proven or putative PVs in one of the mismatch repair genes were included. Cumulative incidences of GC and DC were estimated for high-risk (MLH1, MSH2 and EpCAM) and low-risk (MSH6 and PMS2) PVs using competing risk methodology (Fine and Gray method) with death due to other causes as competing risk.

Findings

Among 1002 individuals with high-risk and 765 individuals with low-risk PVs, 29 GCs (1.6%) and 39 DCs (2.2%) were diagnosed. Cumulative incidence of GC and DC under the age of 50 was very low (≤1%) for all individuals. At age 70 and 75, cumulative incidence of GC was 3% [95% CI 1%-5%] and 5% [3%-8%] for high-risk PVs and 1% [0%-2%] and 1% [0%-2%] for low-risk PVs (p = 0.006). For DC, cumulative incidence at age 70 and 75 was 5% [3%-7%] and 6% [3%-8%] in high-risk, 1% [0%-1%] and 2% [0%-4%] in low-risk PVs, respectively (p = 0.01). Primary tumour resection was performed in 62% (18/29) of GCs and 77% (30/39) of DC cases. Early-stage GC, defined as TNM stage I, was found in 32% (9/28) of GCs. Early-stage DC, defined as TNM stage I-IIa, was found in 39% (14/36) of DCs.

Interpretation

Individuals with MLH1, MSH2, and EpCAM PVs have an increased risk of developing GC and DC at the age of 70 years, but this risk is very low before the age of 50 years. The age of onset of surveillance, the yield of GC and DC during EGD surveillance, and its cost-effectiveness should be subject of future studies.

Funding

None.

Lynch Syndrome: From Multidisciplinary Management to Precision Prevention

BACKGROUND AND AIMS

Lynch syndrome (LS) is currently one of the most prevalent hereditary cancer conditions, accounting for 3% of all colorectal cancers and for up to 15% of those with DNA mismatch repair (MMR) deficiency, and it was one of the first historically identified. The understanding of the molecular carcinogenesis of LS tumors has progressed significantly in recent years. We aim to review the most recent advances in LS research and explore genotype-based approaches in surveillance, personalized cancer prevention, and treatment strategies.

METHODS

PubMed was searched to identify relevant studies, conducted up to December 2023, investigating molecular carcinogenesis in LS, surveillance strategies, cancer prevention, and treatment in LS tumors.

RESULTS

Multigene panel sequencing is becoming the benchmark in the diagnosis of LS, allowing for the detection of a pathogenic constitutional variant in one of the MMR genes. Emerging data from randomized controlled trials suggest possible preventive roles of resistant starch and/or aspirin in LS. Vaccination with immunogenic frameshift peptides appears to be a promising approach for both the treatment and prevention of LS-associated cancers, as evidenced by pre-clinical and preliminary phase 1/2a studies.

CONCLUSIONS

Although robust diagnostic algorithms, including prompt testing of tumor tissue for MMR defects and referral for genetic counselling, currently exist for suspected LS in CRC patients, the indications for LS screening in cancer-free individuals still need to be refined and standardized. Investigation into additional genetic and non-genetic factors that may explain residual rates of interval cancers, even in properly screened populations, would allow for more tailored preventive strategies.

Coordinated prospective follow-up of Lynch syndrome is able to detect the majority of incident cancers

BACKGROUND

Lynch syndrome is one of the most common genetic predispositions to many cancers, most of which do not have a consensus recommendation for screening.

AIMS

We studied in our region the value of a systematized and coordinated follow-up program for patients with Lynch syndrome on all organs at risk.

METHODS

A multicenter prospective cohort evaluation was performed, from January 2016 to June 2021.

RESULTS

One hundred and seventy-eight patients were prospectively included (104 women (58%), median age 44 years, range 35-56 years) with a median follow-up of 4 years (range 2.5-5 years), corresponding to a total of 652 patient-years. The overall cancer incidence rate was 13.80 per 1000 patient-years. Seven of nine cancers (78%) were detected during the follow-up program, with all cancers identified at an early stage. The detection rate of adenomas during colonoscopies was 24%.

CONCLUSION

These preliminary data suggest that coordinated prospective follow-up of Lynch syndrome is capable of detecting the majority of incident cancers, particularly for locations not covered by an international follow-up recommendation. However, these results need to be confirmed by larger-scale studies.

Metachronous colorectal cancer risk according to Lynch syndrome pathogenic variant after extensive versus partial colectomy in the Netherlands: a retrospective cohort study

BACKGROUND

Extensive colectomy (subtotal or total colectomy) is often advised for carriers of Lynch syndrome with colorectal cancer. However, the risk of metachronous colorectal cancer might differ by Lynch syndrome variant, meaning that partial colectomy, which has better functional outcomes, might be adequate for some patients with low-risk variants. We aimed to assess the risk of metachronous colorectal cancer after partial colectomy and extensive colectomy in carriers of Lynch syndrome with different pathogenic variants.

METHODS

For this retrospective cohort study, carriers of Lynch syndrome with colorectal cancer in the Netherlands were identified by linkage of the Dutch Foundation for the Detection of Hereditary Tumors (StOET) database and the Dutch Nationwide Network and Registry of Histopathology and Cytopathology (PALGA) database. Data on demographics, Lynch syndrome variants, colorectal cancers, surgery types, mortality, and surveillance colonoscopies were extracted. Data on colorectal cancer and surveillance colonoscopies were updated until Feb 28, 2022. Data on survival status was updated until Feb 7, 2022. MLH1, MSH2, and EPCAM were classified as high-risk variants and MSH6 and PMS2 as low-risk variants. Patients for whom the type of surgery was unknown were excluded. Cox regression time-to-event analyses were done to assess the risk of metachronous colorectal cancer in four subgroups based on pathogenic variant (high-risk vs low-risk variants) and the extent of surgery (extensive colectomy vs partial colectomy). Sex, age at the time of primary colorectal cancer, primary colorectal cancer stage, performance of surveillance colonoscopies, adherence to the surveillance guidelines, and time period of primary colorectal cancer diagnosis were added to the model as possible confounders. Metachronous colorectal cancer was defined as colorectal cancer diagnosed more than 6 months after the primary colorectal cancer. Patients were censored at time of death or assembly of the database.

FINDINGS

Of 1908 carriers of Lynch syndrome registered in StOET, 532 with a history of colorectal cancer were identified after linkage with PALGA. Five carriers were excluded because of an unknown surgery type, leaving 527 in our sample (mean age at primary colorectal cancer 48·7 years [SD 12·1]; 274 [52%] male and 253 [48%] female). 121 (23%) patients developed metachronous colorectal cancer (median time from primary colorectal cancer to metachronous colorectal cancer 11·0 years [IQR 2·1-17·8]). Metachronous colorectal cancer occurred in 12 (12%) of 97 patients with high-risk variants and extensive colectomy, in 85 (32%) of 267 patients with high-risk variants and partial colectomy, in zero (0%) of 11 patients with low-risk variants and extensive colectomy, and in 24 (16%) of 152 patients with low-risk variants and partial colectomy. Partial colectomy was associated with a higher risk of metachronous colorectal cancer than extensive colectomy in the high-risk variant group (hazard ratio 1·97, 95% CI 1·04-3·73; p=0·039). The risk of metachronous colorectal cancer did not differ between carriers of low-risk variants who had partial colectomy and those of high-risk variants who had extensive colectomy (1·14, 0·55-2·36; p=0·72).

INTERPRETATION

The risk of metachronous colorectal cancer after partial colectomy in carriers of low-risk variants is similar to the risk after extensive colectomy in carriers of high-risk variants. This finding suggests that partial colectomy followed by endoscopic surveillance is an appropriate management approach to treat colorectal cancer in carriers of low-risk Lynch syndrome variants.

FUNDING

None.

Role of colonoscopy in colorectal cancer screening: Available evidence

Colonoscopy is the cornerstone examination for colorectal cancer (CRC) screening and it is recommended as the first examination in the context of individuals with high risk of CRC development. Thereby, this examination is of choice in the setting of patients with hereditary CRC syndromes or in patients with long-standing inflammatory bowel disease with colon involvement. However, its role is less clear in the average risk-risk population and in patients with family history of CRC not linked to hereditary CRC syndromes. Despite this, current guidelines, include colonoscopy as alternative for CRC screening either in average risk population with the same evidence level that other screening strategies or in the familial risk population. The present manuscript reviews the clinical evidence on the role of colonoscopy in preventing CRC in different screening settings.

Preventive strategies in familial and hereditary colorectal cancer

Colorectal cancer is a leading cause of cancer-related deaths worldwide. While most cases are sporadic, a significant proportion of cases are associated with familial and hereditary syndromes. Individuals with a family history of colorectal cancer have an increased risk of developing the disease, and those with hereditary syndromes such as Lynch syndrome or familial adenomatous polyposis have a significantly higher risk. In these populations, preventive strategies are critical for reducing the incidence and mortality of colorectal cancer. This review provides an overview of current preventive strategies for individuals at increased risk of colorectal cancer due to familial or hereditary factors. The manuscript includes a discussion of risk assessment and genetic testing, highlighting the importance of identifying at-risk individuals and families. This review describes various preventive measures, including surveillance colonoscopy, chemoprevention, and prophylactic surgery, and their respective benefits and limitations. Together, this work highlights the importance of preventive strategies in familial and hereditary colorectal cancer.

Colonoscopy surveillance in Lynch syndrome is burdensome and frequently delayed

Individuals with Lynch syndrome have an increased colorectal cancer risk, hence, biennial colonoscopy surveillance is recommended. We aimed to investigate patients' perception and preferences regarding surveillance, and to further explore compliance behaviour. Individuals with Lynch syndrome received a validated survey evaluating experiences of their three most recent colonoscopies. Individuals were non-compliant to surveillance if the interval between colonoscopies differed ≥ 6 months from the recommended interval. In total, 197 of 291 (68%) invited individuals returned the survey. They mostly underwent colonoscopy biennially (99%), under mild sedation (79%) and with bowel preparation performed by Moviprep® (99%). Surveillance was perceived as impacting quality of life in 21%, and as moderately to extremely burdensome in 57%, particularly in those below age 40. To lower the burden, patients prioritised improvements in volume and taste of bowel preparation, laxation-related bowel movements, waiting times, and a more personal and respectful approach of endoscopic staff. Additionally, many individuals (60%) would favour less-invasive surveillance modalities such as biomarkers. In total, 28% of individuals had delayed colonoscopy surveillance, predominantly for patient-related reasons. An additional 10% considered quitting/postponing surveillance. Upon multivariable analysis, patient-related delay was associated with low and medium education, history of ≤ 4 colonoscopies and having no hospital recall-system. Colonoscopy surveillance in Lynch syndrome is often experienced as burdensome, and frequently delayed. We identified determinants of surveillance behaviour in this population, and present potential interventions to reduce the burden and non-compliance rates.

The Role of Colonoscopy in the Management of Individuals with Lynch Syndrome: A Narrative Review

The history of Lynch syndrome changed definitively in 2000, when a study published in Gastroenterology demonstrated a significant reduction in mortality among individuals with Lynch syndrome who undergo regular endoscopic surveillance. As a consequence of this clinical evidence, all scientific societies developed guidelines, which highlighted the role of colonoscopy in the management of Lynch syndrome, especially for individuals at high risk of colorectal cancer. Over the years, these guidelines were modified and updated. Specialized networks were developed in order to standardize endoscopic surveillance programs and evaluate all the clinical data retrieved by the results of colonoscopies performed for both the screening and the surveillance of individuals with Lynch syndrome. Recent data show that the impact of colonoscopy (with polypectomy) on the prevention of colorectal cancer in individuals with Lynch syndrome is less significant than previously thought. This narrative review summarizes the current discussion, the hypotheses elaborated and the algorithms depicted for the management of individuals with Lynch Syndrome on the basis of the recent data published in the literature.

Evaluating colonoscopy screening intervals in patients with Lynch syndrome from a large Canadian registry

BACKGROUND

Lynch syndrome (LS) screening guidelines originally recommended colonoscopy every 1 to 2 years, beginning between the ages of 20 and 25 years. Recent studies have questioned the benefits of these short screening intervals in preventing colorectal cancer (CRC). Our goal is to determine how colonoscopy screening intervals impact CRC in patients with LS.

METHODS

We analyzed the demographics, screening practices, and outcomes of patients with LS identified through the clinic based Familial Gastrointestinal Cancer Registry at the Zane Cohen Centre, Sinai Health System, Toronto, Canada.

RESULTS

A total of 429 patients with LS were identified with median follow-up of 9.2 years; 44 developed CRC. We found a positive trend between shorter screening intervals and the number of adenomas detected during colonoscopy. Any new adenoma detected at screening decreased 10-year CRC incidence by 11.3%. For MLH1 carriers, a screening interval of 1-2 years vs 2-3 years led to a 20-year cumulative CRC risk reduction of 28% and 14% in females and males, respectively. For MSH2 carriers, this risk reduction was 29% and 17%, respectively, and for male MSH6 carriers 18%. Individuals without any adenomas detected (53.4% of LS carriers) had an increased 20-year CRC risk of 25.7% and 57.2% for women and men, respectively, compared with those diagnosed with adenomas at screening.

CONCLUSIONS

The recommended colonoscopy screening interval of 1-2 years is efficient at detecting adenomas and reducing CRC risk. The observation that 53.4% of LS patients never had an adenoma warrants further investigation about a possible adenoma-free pathway.

Updates in the diagnosis and management of non-ampullary small-bowel polyposis

Advances in endoscopic instruments and techniques changed the strategy of diagnosis and management for non-ampullary small-bowel polyposis. In patients with Peutz-Jeghers syndrome, gastrointestinal surveillance using capsule endoscopy should commence no later than eight years old. Small bowel polyps >15 mm should be treated to prevent intussusception. Recently, endoscopic ischemic polypectomy and endoscopic reduction of intussusception were described. In patients with familial adenomatous polyposis, the first endoscopic screening using a lateral viewing and a longer endoscope to check the proximal jejunum should be performed around 25 years. Some experts recommend a first duodenal examination with a first colonoscopy (13 years). The surveillance intervals for duodenal polyposis should be adjusted individually. ESGE recommended the resection of every adenoma larger than 1 cm. Cold snare polypectomy has the potential to change the threshold of size for endoscopic resection. In patients with Juvenile polyposis syndrome, small bowel involvement seems infrequent and mostly located in the duodenal part. There is no indication for distal small bowel investigation.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

Germline Variants in MLH1 and ATM Genes in a Young Patient with MSI-H in a Precancerous Colonic Lesion

Lynch syndrome (LS) is an autosomal dominant inherited disorder that primarily predisposes individuals to colorectal and endometrial cancer. It is associated with pathogenic variants in DNA mismatch repair (MMR) genes. In this study, we report the case of a 16-year-old boy who developed a precancerous colonic lesion and had a clinical suspicion of LS. The proband was found to have a somatic MSI-H status. Analysis of the coding sequences and flanking introns of the MLH1 and MSH2 genes by Sanger sequencing led to the identification of the variant of uncertain significance, namely, c.589-9_589-6delGTTT in the MLH1 gene. Further investigation revealed that this variant was likely pathogenetic. Subsequent next-generation sequencing panel analysis revealed the presence of two variants of uncertain significance in the ATM gene. We conclude that the phenotype of our index case is likely the result of a synergistic effect of these identified variants. Future studies will allow us to understand how risk alleles in different colorectal-cancer-prone genes interact with each other to increase an individual's risk of developing cancer.

Telomere Length as a New Risk Marker of Early-Onset Colorectal Cancer

Early-onset colorectal cancer (EOCRC; age younger than 50 years) incidence has been steadily increasing in recent decades worldwide. The need for new biomarkers for EOCRC prevention strategies is undeniable. In this study, we aimed to explore whether an aging factor, such as telomere length (TL), could be a useful tool in EOCRC screening. The absolute leukocyte TL from 87 microsatellite stable EOCRC patients and 109 healthy controls (HC) with the same range of age, was quantified by Real Time Quantitative PCR (RT-qPCR). Then, leukocyte whole-exome sequencing (WES) was performed to study the status of the genes involved in TL maintenance (hTERT, TERC, DKC1, TERF1, TERF2, TERF2IP, TINF2, ACD, and POT1) in 70 sporadic EOCRC cases from the original cohort. We observed that TL was significantly shorter in EOCRC patients than in healthy individuals (EOCRC mean: 122 kb vs. HC mean: 296 kb; p < 0.001), suggesting that telomeric shortening could be associated with EOCRC susceptibility. In addition, we found a significant association between several SNPs of hTERT (rs79662648), POT1 (rs76436625, rs10263573, rs3815221, rs7794637, rs7784168, rs4383910, and rs7782354), TERF2 (rs251796 and rs344152214), and TERF2IP (rs7205764) genes and the risk of developing EOCRC. We consider that the measurement of germline TL and the status analysis of telomere maintenance related genes polymorphisms at early ages could be non-invasive methods that could facilitate the early identification of individuals at risk of developing EOCRC.

A Focused Clinical Review of Lynch Syndrome

Lynch syndrome (LS) is an autosomal dominant condition that increases an individual's risk of a constellation of cancers. LS is defined when an individual has inherited pathogenic variants in the mismatch repair genes. Currently, most people with LS are undiagnosed. Early detection of LS is vital as those with LS can be enrolled in cancer reduction strategies through chemoprophylaxis, risk reducing surgery and cancer surveillance. However, these interventions are often invasive and require refinement. Furthermore, not all LS associated cancers are currently amenable to surveillance. Historically only those with a strong family history suggestive of LS were offered testing; this has proved far too restrictive. New criteria for testing have recently been introduced including the universal screening for LS in associated cancers. This has increased the number of people being diagnosed with LS but has also brought about unique challenges such as when to consent for germline testing and questions over how and who should carry out the consent. The results of germline testing for LS can be complicated and the diagnostic pathway is not always clear. Furthermore, by testing only those with cancer for LS we fail to identify these individuals before they develop potentially fatal pathology. This review will outline these challenges and explore solutions. Furthermore, we consider the potential future of LS care and the related treatments and interventions which are the current focus of research.

PMS2-associated Lynch syndrome: Past, present and future

Carriers of any pathogenic variant in one of the MMR genes (path_MMR carriers) were traditionally thought to be at comparable risk of developing a range of different malignancies, foremost colorectal cancer (CRC) and endometrial cancer. However, it is now widely accepted that their cancer risk and cancer spectrum range notably depending on which MMR gene is affected. Moreover, there is increasing evidence that the MMR gene affected also influences the molecular pathogenesis of Lynch syndrome CRC. Although substantial progress has been made over the past decade in understanding these differences, many questions remain unanswered, especially pertaining to path_PMS2 carriers. Recent findings show that, while the cancer risk is relatively low, PMS2-deficient CRCs tend to show more aggressive behaviour and have a worse prognosis than other MMR-deficient CRCs. This, together with lower intratumoral immune infiltration, suggests that PMS2-deficient CRCs might have more in common biologically with sporadic MMR-proficient CRCs than with other MMR-deficient CRCs. These findings could have important consequences for surveillance, chemoprevention and therapeutic strategies (e.g. vaccines). In this review we discuss the current knowledge, current (clinical) challenges and knowledge gaps that should be targeted by future studies.

Lynch syndrome: from detection to treatment

Lynch syndrome (LS) is an inherited cancer predisposition syndrome associated with high lifetime risk of developing tumours, most notably colorectal and endometrial. It arises in the context of pathogenic germline variants in one of the mismatch repair genes, that are necessary to maintain genomic stability. LS remains underdiagnosed in the population despite national recommendations for empirical testing in all new colorectal and endometrial cancer cases. There are now well-established colorectal cancer surveillance programmes, but the high rate of interval cancers identified, coupled with a paucity of high-quality evidence for extra-colonic cancer surveillance, means there is still much that can be achieved in diagnosis, risk-stratification and management. The widespread adoption of preventative pharmacological measures is on the horizon and there are exciting advances in the role of immunotherapy and anti-cancer vaccines for treatment of these highly immunogenic LS-associated tumours. In this review, we explore the current landscape and future perspectives for the identification, risk stratification and optimised management of LS with a focus on the gastrointestinal system. We highlight the current guidelines on diagnosis, surveillance, prevention and treatment and link molecular disease mechanisms to clinical practice recommendations.

Potential risks associated with the use of ionizing radiation for imaging and treatment of colorectal cancer in Lynch syndrome patients

The aim of this review is to investigate the literature pertaining to the potential risks of low-dose ionizing radiation to Lynch syndrome patients by use of computed tomography (CT), either diagnostic CT colonography (CTC), standard staging CT or CT surveillance. Furthermore, this review explores the potential risks of using radiotherapy for treatment of rectal cancer in these patients. No data or longitudinal observational studies of the impact of radiation exposure on humans with Lynch syndrome were identified. Limited experimental studies utilizing cell lines and primary cells exposed to both low and high radiation doses have been carried out to help determine radio-sensitivity associated with DNA mismatch repair gene deficiency, the defining feature of Lynch syndrome. On balance, these studies suggest that mismatch repair deficient cells may be relatively radio-resistant (particularly for low dose rate exposures) with higher mutation rates, albeit no firm conclusions can be drawn. Mouse model studies, though, showed an increased risk of developing colorectal tumors in mismatch repair deficient mice exposed to radiation doses around 2 Gy. With appropriate ethical approval, further studies investigating radiation risks associated with CT imaging and radiotherapy relevant doses using cells/tissues derived from confirmed Lynch patients or genetically modified animal models are urgently required for future clinical guidance.

Endoscopic surveillance of Lynch syndrome at a highly specialized center in Sweden: An observational study of interval colorectal cancer and individual risk factors

Introduction

Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC). In order to detect CRCs amongst LS patients, regular colonoscopies are recommended. However, an international agreement on an optimal surveillance interval has not yet been reached. In addition, few studies have investigated factors that could potentially increase the CRC risk amongst LS patients.

Aims

The primary aim was to describe the frequency of CRCs detected during endoscopic surveillance and to estimate the interval from a clean colonoscopy to CRC detection amongst LS patients. The secondary aim was to investigate individual risk factors, including sex, LS genotype, smoking, aspirin use and body mass index (BMI), on CRC risk amongst patients that develop CRC before and during surveillance.

Material and methods

Clinical data and colonoscopy findings from 366 LS patients' 1437 surveillance colonoscopies were collected from medical records and patient protocols. Logistic regression and Fisher's exact test were used to investigate associations between individual risk factors and CRC development. Mann-Whitney U test was used to compare the distribution of TNM stages of CRC detected before surveillance and after index.

Results

CRC was detected in 80 patients before surveillance and in 28 patients during surveillance (10 at index and 18 after index). During the surveillance programme, CRC was detected within 24 months in 65% of the patients, and after 24 months within 35% of the patients. CRC was more common amongst men, previous and current smokers, and the odds of developing CRC also increased with an increasing BMI. CRCs were more often detected amongst MLH1 and MSH2 carriers during surveillance, compared to the other genotypes.

Conclusions

We found that 35% of the CRC cases detected during surveillance were found after 24 months. MLH1 and MSH2 carriers were at higher risk of developing CRC during surveillance. Additionally, men, current or previous smokers, and patients with a higher BMI were at higher risk of developing CRC. Currently, LS patients are recommended a "one-size-fits-all" surveillance program. The results support the development of a risk-score whereby individual risk factors should be taken into consideration when deciding on an optimal surveillance interval.

Case Report: Multiple colorectal cancers in a patient with Ulcerative colitis and Lynch syndrome: Is there a role for prophylactic colectomy? A short report and review of literature

It is a known fact that Lynch syndrome (LS) and Ulcerative colitis (UC) are individually associated with increased risk of colorectal cancer. While there is no conclusive evidence to demonstrate a cumulative risk when these two conditions coexist, available data suggest early onset and synchronous cancers are synonymous to this group. We have reported an unusual case of multiple synchronous colorectal cancers in a young man with ulcerative colitis and Lynch syndrome also known as Hereditary Nonpolyposis Colorectal Cancer (HNPCC) gene mutation. We propose that conducting a detailed genetic mutation profile in LS patients may play a key role in guiding the intensity of endoscopic surveillance and that a concerted, pragmatic, patient guided approach should be adopted on the subject of prophylactic colectomy when UC and LS co-exist.

Familial component of early-onset colorectal cancer: opportunity for prevention

BACKGROUND

Individuals with a non-syndromic family history of colorectal cancer are known to have an increased risk. There is an opportunity to prevent early-onset colorectal cancer (age less than 50 years) (EOCRC) in this population. The aim was to explore the proportion of EOCRC that is preventable due to family history of colorectal cancer.

METHODS

This was a retrospective multicentre European study of patients with non-hereditary EOCRC. The impact of the European Society of Gastrointestinal Endoscopy (ESGE), U.S. Multi-Society Task Force (USMSTF), and National Comprehensive Cancer Network (NCCN) guidelines on prevention and early diagnosis was compared. Colorectal cancer was defined as potentially preventable if surveillance colonoscopy would have been performed at least 5 years before the age of diagnosis of colorectal cancer, and diagnosed early if colonoscopy was undertaken between 1 and 4 years before the diagnosis.

RESULTS

Some 903 patients with EOCRC were included. Criteria for familial colorectal cancer risk in ESGE, USMSTF, and NCCN guidelines were met in 6.3, 9.4, and 30.4 per cent of patients respectively. Based on ESGE, USMSTF, and NCCN guidelines, colorectal cancer could potentially have been prevented in 41, 55, and 30.3 per cent of patients, and diagnosed earlier in 11, 14, and 21.1 per cent respectively. In ESGE guidelines, if surveillance had started 10 years before the youngest relative, there would be a significant increase in prevention (41 versus 55 per cent; P = 0.010).

CONCLUSION

ESGE, USMSTF, and NCCN criteria for familial colorectal cancer were met in 6.3, 9.4, and 30.4 per cent of patients with EOCRC respectively. In these patients, early detection and/or prevention could be achieved in 52, 70, and 51.4 per cent respectively. Early and accurate identification of familial colorectal cancer risk and increase in the uptake of early colonoscopy are key to decreasing familial EOCRC.

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.

Risk factors for gastric cancer in patients with Lynch syndrome

INTRODUCTION

The cumulative lifetime risk of gastric cancer (GC) in patients with Lynch syndrome (LS) is reported to be 8%. There is limited evidence on specific risk factors for GC and no agreement among guidelines on gastric endoscopic surveillance schedule in LS patients.

AIMS AND METHODS

We conducted a retrospective cohort study to identify risk factors for gastric precancerous conditions (chronic atrophic gastritis and intestinal metaplasia) and GC in patients with LS and a case-control study to compare the prevalence of these conditions with a control group.

RESULTS

We included 385 LS patients (40.5% male, mean age 49.0 years). During a median follow-up period of 48 months (interquartile range, 24-84 months), precancerous conditions were identified in 110 patients (34%) and the prevalence of advanced stages of atrophic gastritis was 3% for OLGA III/IV and 0.6% OLGIM III/IV. Family history of GC was significantly associated with OLGA III/IV ( P = 0.020). Among LS patients, 10 patients (2.6%) were diagnosed with GC (incidence rate of 5/1000 persons-year). Older age and OLGA III/IV were identified as risk factors for GC ( P < 0.001). When compared with controls, patients with LS had significantly higher rates of Hp infection ( P = 0.035) and lower OLGA and OLGIM stages ( P < 0.001 and P = 0.026, respectively).

CONCLUSION

In our cohort, the incidence of GC and advanced stages of atrophic gastritis was low. Older age and OLGA III/IV were associated with a higher risk of GC. Identification of risk factors for GC in LS patients can help tailoring endoscopic surveillance.

Lynch Syndrome: From Carcinogenesis to Prevention Interventions

Simple Summary

Promoting proper preventive interventions to reduce morbidity and mortality is one of the most important challenges pertaining to inherited conditions. Lynch syndrome (LS) is an inherited disorder that predisposes to several kinds of tumor and is responsible for a relevant proportion of human colorectal and endometrial cancers. Recent knowledge has allowed for a better understanding of the genetic cause, pathogenesis, underlying immunological mechanisms, epidemiological distribution, and prevalence of this disease. This opens up unpredictable perspectives of translating such knowledge into validated programs for prevention and surveillance, in order to reduce the health impact of this disease through medical interventions before cancer development. In our review, we summarize the updated guidelines of the screening, surveillance, and risk-reducing strategies for LS patients. Moreover, we present novel opportunities in the treatment and prevention of LS patients through harnessing the immune system using immunocheckpoint inhibitors and vaccines.

Abstract

Lynch syndrome (LS) is the most common inherited disorder responsible for an increased risk of developing cancers at different sites, most frequently in the gastrointestinal and genitourinary tracts, caused by a germline pathogenic variant affecting the DNA mismatch repair system. Surveillance and risk-reducing procedures are currently available and warranted for LS patients, depending on underlying germline mutation, and are focused on relevant targets for early cancer diagnosis or primary prevention. Although pharmacological approaches for preventing LS-associated cancer development were started many years ago, to date, aspirin remains the most studied drug intervention and the only one suggested by the main surveillance guidelines, despite the conflicting findings. Furthermore, we also note that remarkable advances in anticancer drug discovery have given a significant boost to the application of novel immunological strategies such as immunocheckpoint inhibitors and vaccines, not only for cancer treatment, but also in a preventive setting. In this review, we outline the clinical, biologic, genetic, and morphological features of LS as well as the recent three-pathways carcinogenesis model. Furthermore, we provide an update on the dedicated screening, surveillance, and risk-reducing strategies for LS patients and describe emerging opportunities of harnessing the immune system.

Diagnosis and management of Lynch syndrome

Lynch syndrome (LS) is a dominantly inherited cancer susceptibility syndrome defined by presence of pathogenic variants in DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or in deletions of the EPCAM gene. Although LS is present in about 1 in 400 people in the UK, it estimated that only 5% of people with this condition are aware of the diagnosis. Therefore, testing for LS in all new diagnoses of colorectal or endometrial cancers is now recommended in the UK, and gastroenterologists can offer 'mainstreamed' genetic testing for LS to patients with cancer. Because LS results in a high lifetime risk of colorectal, endometrial, gastric, ovarian, hepatobiliary, brain and other cancers, the lifelong care of affected individuals and their families requires a coordinated multidisciplinary approach. Interventions such as high-quality 2-yearly colonoscopy, prophylactic gynaecological surgery, and aspirin are proven to prevent and facilitate early diagnosis and prevention of cancers in this population, and improve patient outcomes. Recently, an appreciation of the mechanism of carcinogenesis in LS-associated cancers has contributed to the development of novel therapeutic and diagnostic approaches, with a gene-specific approach to disease management, with potential cancer-preventing vaccines in development. An adaptive approach to surgical or oncological management of LS-related cancers may be considered, including an important role for novel checkpoint inhibitor immunotherapy in locally advanced or metastatic disease. Therefore, a personalised approach to lifelong gene-specific management for people with LS provides many opportunities for cancer prevention and treatment which we outline in this review.

Systematic review: non-endoscopic surveillance for colorectal neoplasia in individuals with Lynch syndrome

BACKGROUND

Individuals with Lynch syndrome are at high risk for colorectal cancer (CRC). Regular colonoscopies have proven to decrease CRC incidence and mortality. However, colonoscopy is burdensome and interval CRCs still occur. Hence, an accurate, less-invasive screening method that guides the timing of colonoscopy would be of important value.

AIM

To outline the performance of non-endoscopic screening modalities for Lynch-associated CRC and adenomas.

METHODS

Systematic literature search in MEDLINE and EMBASE to identify studies investigating imaging techniques and biomarkers for detection of CRC and adenomas in Lynch syndrome. The QUADAS-2 tool was used for the quality assessment of included studies.

RESULTS

Seven of 1332 screened articles fulfilled the inclusion criteria. Two studies evaluated either CT colonography or MR colonography; both techniques were unable to detect CRC and (advanced) adenomas <10 mm. The other five studies evaluated plasma methylated-SEPTIN9, faecal immunochemical test (FIT), faecal tumour DNA markers (BAT-26, hMLH1, p53, D9S171, APC, D9S162, IFNA and DCC) and faecal microbiome as screening modalities. Sensitivity for CRC varied from 33% (BAT-26) to 70% (methylated-SEPTIN9) to 91% (hMLH1). High specificity (94-100%) for CRC and/or adenomas was observed for methylated-SEPTIN9, FIT and BAT-26. Desulfovibrio was enriched in the stool of patients having adenomas. However, all these studies were characterised by small populations, high/unclear risk of bias and/or low prevalence of adenomas.

CONCLUSIONS

Imaging techniques are unsuitable for colon surveillance in Lynch syndrome, whereas biomarkers are understudied. Having outlined biomarker research in Lynch-associated and sporadic CRC/adenomas, we believe that these non-invasive markers may hold potential (whether or not combined) for this population. As they could be of great value, (pre-)clinical studies in this field should be prioritised.

Bacteria-Mediated Modulatory Strategies for Colorectal Cancer Treatment

Colorectal cancer (CRC) is one of the most common tumors worldwide, with a higher rate of distant metastases than other malignancies and with regular occurrence of drug resistance. Therefore, scientists are forced to further develop novel and innovative therapeutic treatment strategies, whereby it has been discovered microorganisms, albeit linked to CRC pathogenesis, are able to act as highly selective CRC treatment agents. Consequently, researchers are increasingly focusing on bacteriotherapy as a novel therapeutic strategy with less or no side effects compared to standard cancer treatment methods. With multiple successful trials making use of various bacteria-associated mechanisms, bacteriotherapy in cancer treatment is on its way to become a promising tool in CRC targeting therapy. In this study, we describe the anti-cancer effects of bacterial therapy focusing on the treatment of CRC as well as diverse modulatory mechanisms and techniques that bacteriotherapy offers such as bacterial-related biotherapeutics including peptides, toxins, bacteriocins or the use of bacterial carriers and underlying molecular processes to target colorectal tumors.

Lynch syndrome; towards more personalized management?

Lynch syndrome is the most common inherited cause of colorectal (lifetime risk up to 70%) and endometrial cancer. The diagnosis of Lynch syndrome facilitates preventive measures aimed at reducing the incidence and mortality of cancer. Colonoscopic surveillance for colorectal cancer, aspirin, and prophylactic hysterectomy and bilateral salpo-oopherectomy for endometrial and/or ovarian cancer have demonstrated to effectively reduce cancer mortality in this population. However, the lifetime risk of each cancer in people with Lynch syndrome is gene-specific and may be modified by environmental factors. Furthermore, the benefits of surveillance strategies need to be balanced against the risk of over-diagnosis and be supported by evidence of improved outcomes from cancer diagnosis in surveillance. Therefore, people with Lynch syndrome may benefit from a personalized management approach.

Familial colorectal cancer

The introduction of average-risk colorectal cancer (CRC) screening programs means that many subjects with family history of CRC and without well-described inherited syndromes can benefit from these public health policies. Therefore, the definition of which individuals should be named under the umbrella of the term "familial CRC" should be reconsidered to include only those who are outside of the protection of population-based screening and need to be moved towards a more intensive surveillance strategy. Two subgroups have been reported as having a high enough CRC risk to be included within the term "familial risk of CRC": individuals who have ≥1 first degree relative (FDR) with CRC diagnosed at age <50 years, and those who have ≥2 FDRs with CRC. Colonoscopy-based screening starting at age 40 years is proposed as the most accepted recommendation for these individuals. Finally, the evolution of Lynch syndrome screening from clinical criteria to tumor tissue analysis and new tools for screening pathogenic gene mutations associated with cancer susceptibility in individuals with early-onset CRC might help to reduce misclassification of familial CRC.

Management of familial adenomatous polyposis and MUTYH-associated polyposis; new insights

Familial adenomatous polyposis (FAP) and MUTYH-associated polyposis (MAP) are rare inherited polyposis syndromes with a high colorectal cancer (CRC) risk. Therefore, frequent endoscopic surveillance including polypectomy of relevant premalignant lesions from a young age is warranted in patients. In FAP and less often in MAP, prophylactic colectomy is indicated followed by lifelong endoscopic surveillance of the retained rectum after (sub)total colectomy and ileal pouch after proctocolectomy to prevent CRC. No consensus is reached on the right type and timing of colectomy. As patients with FAP and MAP nowadays have an almost normal life-expectancy due to adequate treatment of colorectal polyposis, challenges in the management of FAP and MAP have shifted towards the treatment of duodenal and gastric adenomas as well as desmoid treatment in FAP. Whereas up until recently upper gastrointestinal surveillance was mostly diagnostic and patients were referred for surgery once duodenal or gastric polyposis was advanced, nowadays endoscopic treatment of premalignant lesions is widely performed. Aiming to reduce polyp burden in the colorectum as well as in the upper gastrointestinal tract, several chemopreventive agents are currently being studied.

Hereditary pancreatic cancer

Pancreatic cancer is one of the deadliest malignancies. Therefore, there is an urgent need to detect pancreatic cancer in an earlier stage to improve outcomes. A variety of hereditary cancer syndromes have been associated with an increased risk of developing pancreatic cancer, and these individuals may benefit from surveillance programs. Surveillance programs have shown potential to improve outcomes, but have important risks such as overtreatment. In this review we will discuss the definitions and epidemiology of hereditary pancreatic cancer, recommendations for genetic testing and participation in surveillance. Important aspects are differences in surveillance strategies, target lesions, and potential benefits and harms of surveillance. Lastly we will highlight future directions for research and improvement of care for individuals at high-risk of pancreatic cancer.

The "diagnose and leave in" strategy for diminutive rectosigmoid polyps in Lynch syndrome: a post hoc analysis from a randomized controlled trial

BACKGROUND

The "diagnose-and-leave-in" policy has been established to reduce the risks and costs related to unnecessary polypectomies in the average-risk population. In individuals with Lynch syndrome, owing to accelerated carcinogenesis, the general recommendation is to remove all polyps, irrespective of size, location, and appearance. We evaluated the feasibility and safety of the diagnose-and-leave-in strategy in individuals with Lynch syndrome. METHODS : We performed a post hoc analysis based on per-polyp data from a randomized, clinical trial conducted by 24 dedicated colonoscopists at 14 academic centers, in which 256 patients with confirmed Lynch syndrome underwent surveillance colonoscopy from July 2016 to January 2018. In vivo optical diagnosis with confidence level for all detected lesions was obtained before polypectomy using virtual chromoendoscopy alone or with dye-based chromoendoscopy. Primary outcome was the negative predictive value (NPV) for neoplasia of high-confidence optical diagnosis among diminutive (≤ 5 mm) rectosigmoid lesions. Histology was the reference standard.

RESULTS

Of 147 rectosigmoid lesions, 128 were diminutive. In 103 of the 128 lesions (81 %), the optical diagnostic confidence was high and showed an NPV of 96.0 % (95 % confidence interval [CI] 88.9 %-98.6 %) and accuracy of 89.3 % (95 %CI 81.9 %-93.9 %). By following the diagnose-and-leave-in policy, we would have avoided 59 % (75/128) of polypectomies at the expense of two diminutive low grade dysplastic adenomas and one diminutive sessile serrated lesion that would have been left in situ.

CONCLUSION

In patients with Lynch syndrome, the diagnose-and-leave-in strategy for diminutive rectosigmoid polyps would be feasible and safe.

Adenoma and colorectal cancer risks in Lynch syndrome, Lynch-like syndrome and familial colorectal cancer type X

Lynch syndrome (LS), Lynch-like syndrome (LLS) and familial colorectal cancer type X (FCCX) are different entities of familial cancer predisposition leading to an increased risk of colorectal cancer (CRC). The aim of this prospective study was to characterise and to compare the risks for adenoma and CRC in these three risk groups. Data was taken from the registry of the German Consortium for Familial Intestinal Cancer. Patients were prospectively followed up in an intensified colonoscopic surveillance programme that included annual examinations. Cumulative risks for adenoma and CRC were calculated separately for LS, LLS and FCCX, and then for males and females. Multivariate Cox regression was used to analyse the independent contributions of risk group, mismatch repair gene (within LS), sex and previous adenoma. The study population comprised 1448 individuals (103 FCCX, 481 LLS and 864 LS). The risks were similar for colorectal adenomas, but different for first and metachronous CRC between the three risk groups. CRC risk was highest in LS, followed by LLS and lowest in FCCX. Male sex and a prevalent adenoma in the index colonoscopy were associated with a higher risk for incident adenoma and CRC. In patients with LS, CRC risks were particularly higher in female MSH2 than MLH1 carriers. Our study may support the development of risk-adapted surveillance policies in LS, LLS and FCCX.

Colorectal Cancer Screening Recommendations and Outcomes in Lynch Syndrome

Screening for colorectal cancer (CRC) in Lynch syndrome enables early detection and likely cancer prevention. CRC screening guidelines have evolved from universal to gene-specific recommendations based on lifetime neoplasia risks. Regular screening for Lynch syndrome reduces CRC-related mortality; however, high CRC incidence during regular colonoscopy screening suggests the possibility of nonpolypoid carcinogenesis. Colonoscopy is the primary modality for screening for Lynch syndrome with mixed and emerging data on quality metrics, chromoendoscopy, artificial intelligence, and nonendoscopic modalities. Screening adherence varies across studies. In this review, we present the current state of CRC screening recommendations, outcomes, and modalities in Lynch syndrome.

Identification of Lynch Syndrome Carriers among Patients with Small Bowel Adenocarcinoma

Simple Summary

Small bowel adenocarcinoma (SBA) is associated with Lynch syndrome (LS). This is the first study to evaluate the identification of LS patients based on mismatch repair deficiency (MMRd) tumor among SBA. The authors found a 21.3% prevalence of MMRd tumors and a 10.1% prevalence of LS. A germline mutation was identified in 60% of patients with a MMRd tumor. This data suggests that universal tumor MMR testing among SBA patients should be implemented for the identification of LS.

Abstract

Background: Small bowel adenocarcinoma (SBA) is a rare disease which can be associated with Lynch syndrome (LS). LS tumors are characterized by the presence of microsatellite instability (MSI) and/or the loss of mismatch repair (MMR) protein expression. In SBA, the frequency of MMR deficient (MMRd) tumors varies from 5% to 35%. This study aims to describe the prevalence of LS carriers among patients with MMRd small bowel adenocarcinomas. Methods: A multicenter retrospective study with identification and MMR testing of all consecutive SBA between 2004 and 2020 in a multicenter Spanish study. Demographical data, tumor characteristics, follow-up and survival information were collected. Germline testing was driven by identification of MMRd tumors. Results: A total of 94 individuals diagnosed with SBA were recruited. We observed 20 (21.3%) MMRd tumors. In 9/15 (60%) patients with MMRd tumors, a pathogenic variant was identified (three MLH1, four MSH2, one MSH6 and one PMS2). Accordingly, the prevalence of LS among all SBA cases was 10.1%. Conclusions: More than one-fifth of SBA display MMRd and in more than a half is due to LS. Our data supports the implementation of universal MMR tumor testing among SBA for the identification of LS families.

Multi-Gene Panel Testing in Gastroenterology: Are We Ready for the Results?

Genetic testing aims to identify patients at risk for inherited cancer susceptibility. In the last decade, there was a significant increase in the request of broader panels of genes as multi-gene panel testing became widely available. However, physicians may be faced with genetic findings for which there is lack of management evidence, despite some progress in understanding their clinical relevance. In this short review, we discuss the advantages and the drawbacks related to multi-gene panel testing in the setting of a Gastrointestinal Familial Cancer Risk clinic. We also summarize the available recommendations on management of pathogenic variant carriers.

Advances in the Aetiology & Endoscopic Detection and Management of Early Gastric Cancer

Simple Summary

Gastric adenocarcinoma has remained a highly lethal disease. Awareness and recognition of preneoplastic conditions (including gastric atrophy and intestinal metaplasia) using high-resolution white-light endoscopy as well as chromoendoscopy is therefore essential. Helicobacter pylori, a class I carcinogen, remains the main contributor to the development of sporadic distal gastric neoplasia. Management of early gastric neoplasia with endoscopic resections should be in line with standard indications. A multidisciplinary approach to any case of an early gastric neoplasia is imperative. Hereditary forms of gastric cancer require a tailored approach and individua-lized surveillance.

Abstract

The mortality rates of gastric carcinoma remain high, despite the progress in research and development in disease mechanisms and treatment. Therefore, recognition of gastric precancerous lesions and early neoplasia is crucial. Two subtypes of sporadic gastric cancer have been recognized: cardia subtype and non-cardia (distal) subtype, the latter being more frequent and largely associated with infection of Helicobacter pylori, a class I carcinogen. Helicobacter pylori initiates the widely accepted Correa cascade, describing a stepwise progression through precursor lesions from chronic inflammation to gastric atrophy, gastric intestinal metaplasia and neoplasia. Our knowledge on He-licobacter pylori is still limited, and multiple questions in the context of its contribution to the pathogenesis of gastric neoplasia are yet to be answered. Awareness and recognition of gastric atrophy and intestinal metaplasia on high-definition white-light endoscopy, image-enhanced endoscopy and magnification endoscopy, in combination with histology from the biopsies taken accurately according to the protocol, are crucial to guiding the management. Standard indications for endoscopic resections (endoscopic mucosal resection and endoscopic submucosal dissection) of gastric dysplasia and intestinal type of gastric carcinoma have been recommended by multiple societies. Endoscopic evaluation and surveillance should be offered to individuals with an inherited predisposition to gastric carcinoma.

The Role of Diet and Lifestyle in Early-Onset Colorectal Cancer: A Systematic Review

Simple Summary

This systematic review sifted through the exogenous dietary and lifestyle risk factors associated with early-onset colorectal cancer, going through the putative involvement of these exogenous risk factors in epigenetic and microbiota modifications. Given the burden of early-onset colorectal cancer and its globally increasing trend with scant literature on its pathogenesis, we believe it would be of benefit to highlight the importance of further systematic and large studies. Indeed, dietary and lifestyle modification could complement colorectal screening for early-onset colorectal cancer prevention.

Abstract

The incidence of early-onset colorectal cancer, defined as colorectal cancer occurring in young adults under the age of 50, is increasing globally. Knowledge of the etiological factors in young adults is far from complete. Questionable eoCRCs’ exogenous factors are represented by processed meat, sugary drinks, alcohol, Western dietary pattern, overweight and obesity, physical inactivity, and smoking, though with heterogeneous results. Therefore, we performed a systematic review to summarize the current evidence on the role of diet and lifestyle as eoCRC risk factors. We systematically searched PubMed, Scopus, and EMBASE up to July 2021, for original studies evaluating diet, alcohol, physical activity, BMI, and smoking in eoCRC and included twenty-six studies. Indeed, the exogenous factors could represent modifiable key factors, whose recognition could establish areas of future interventions through public health strategies for eoCRC primary prevention. Additionally, we discussed the role of additional non-modifiable risk factors, and of epigenetic regulation and microbiota as mediators of the eoCRC triggered by diet and lifestyle.

Vaccines for Non-Viral Cancer Prevention

Cancer vaccines are a type of immune therapy that seeks to modulate the host’s immune system to induce durable and protective immune responses against cancer-related antigens. The little clinical success of therapeutic cancer vaccines is generally attributed to the immunosuppressive tumor microenvironment at late-stage diseases. The administration of cancer-preventive vaccination at early stages, such as pre-malignant lesions or even in healthy individuals at high cancer risk could increase clinical efficacy by potentiating immune surveillance and pre-existing specific immune responses, thus eliminating de novo appearing lesions or maintaining equilibrium. Indeed, research focus has begun to shift to these approaches and some of them are yielding encouraging outcomes.

False-positive fecal immunochemical test results in colorectal cancer screening and gastrointestinal drug use

PURPOSE

The study aimed to determine the influence of drug treatments (proton pump inhibitors [PPIs] combined with other drugs) on the false-positive (FP) rate in the fecal immunochemical test (FIT).

METHODS

Patients undergoing colonoscopy in the setting of a CRC screening program due to a positive FIT result were included prospectively. Demographic data and drug intake of PPIs, antiplatelet therapy (APA), anticoagulants, selective serotonin reuptake inhibitors (SSRIs), and nonsteroidal anti-inflammatory drugs (NSAIDs) were collected. An FP FIT result was considered normal colonoscopy or with nonneoplastic pathology (NNP). Logistic regression models were used to evaluate the effect of these drugs on the rate of FP FIT results.

RESULTS

We included 515 patients, and 59% (304/515) were males. The rate of FP FIT results was 48% (249/515). Study drug use was higher in patients > 60 years old and females than in those < 60 years old and males (p < 0.001 and p = 0.049, respectively). Multivariate logistic regression revealed that female sex (OR = 2.7 95% CI 1.9-3.9), NNP (OR = 1.5 95% CI 1.1-2.2), and the use of any of the study drugs (OR = 1.4 95% CI 0.9-2.0) were independent risk factors for FP FIT results. The risk of FP FIT results was significantly higher in PPI users than in nonusers (OR = 1.8 95% CI 1.1-2.9), specifically when PPIs were combined with other drugs (OR = 2.01 95% CI 1.1-3.6) only in men.

CONCLUSION

Female sex, NNP, and PPIs combined with other drugs in males were identified as independent risk factors for FP FIT results.

Delta-like ligand 4 level in colorectal cancer is associated with tumor aggressiveness, body mass index and clinical outcome

BACKGROUND

The Notch signaling regulates numerous cell growth, differentiation, and death. However, the expression pattern of its ligand Delta-like 4 (DLL4) in tumors is still uncertain.

OBJECTIVE

In the present study, we examined DLL4 expression in colorectal cancer as well as assessed its role as a prognostic indicator in the present study.

METHODS

DLL4 expression was examined by immunohistochemistry in 265 surgically resected specimens of colorectal cancer and adjacent normal tissues. The relationship between DLL4 expression and clinicopathological characteristics was analyzed. The association of DLL4 expression with the patients' overall survival rate was assessed by Kaplan-Meier and Cox proportional-hazards regression.

RESULTS

Increased DLL4 level was detected in colorectal cancer compared with that of normal tissues. Elevated DLL4 level in colorectal cancer was associated with increased body mass index of patients. Moreover, increased DLL4 level was also found to be correlated with tumor invasion, metastases and unfavorable clinical outcom of patients.

CONCLUSIONS

DLL4 level is increased in colorectal cancer, especially in patients with increased body mass index, indicating potential involvement of obesity-related tumorigenesis and development. It might also serve as a novel molecular marker to predicate outcome of patients.