Uso de paneles de genes en pacientes con alto riesgo de cáncer digestivo hereditario: documento de posicionamiento de la AEG, SEOM, AEGH y consorcio IMPaCT-GENÓMICA / Use of multi-gene panels in patients at high risk of hereditary digestive cancer: position statement of AEG, SEOM, AEGH and IMPaCT-GENÓMICA consortium

Este documento de posicionamiento, auspiciado por la Asociación Española de Gastroenterología, la Sociedad Española de Oncología Médica, la Asociación Española de Genética Humana y el consorcio IMPaCT-Genómica, tiene como objetivo realizar recomendaciones para el uso de paneles de genes en la evaluación de individuos con alto riesgo de cáncer digestivo hereditario. Para medir la calidad de la evidencia y los niveles de recomendación se ha utilizado la metodología basada en el sistema Grading of Recommendations Assessment, Development and Evaluation (GRADE). Se obtuvo el consenso entre expertos mediante un método Delphi. El documento incluye recomendaciones sobre escenarios clínicos en los que se recomienda el uso de paneles de genes en cáncer colorrectal, síndromes polipósicos, cáncer gástrico y pancreático, así como los genes de los paneles a ser considerados en cada una de estas situaciones clínicas. También se establecen recomendaciones sobre la evaluación de mosaicismos, las estrategias de asesoramiento ante la ausencia de sujeto índice y, finalmente, el análisis constitucional tras identificación de variantes patogénicas tumorales. (AU)

This position statement, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Oncología Médica, the Asociación Española de Genética Humana and the IMPaCT-Genómica Consortium aims to establish recommendations for use of multi-gene panel testing in patients at high risk of hereditary gastrointestinal and pancreatic cancer. To rate the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We reached a consensus among experts using a Delphi method. The document includes recommendations on clinical scenarios where multi-gene panel testing is recommended in colorectal cancer, polyposis syndromes, gastric and pancreatic cancer, as well as the genes to be considered in each clinical scenario. Recommendations on the evaluation of mosaicisms, counseling strategies in the absence of an index subject and, finally, constitutional analysis after identification of pathogenic tumor variants are also made. (AU)

Use of multi-gene panels in patients at high risk of hereditary digestive cancer: position statement of AEG, SEOM, AEGH and IMPaCT-GENÓMICA consortium. / Uso de paneles de genes en pacientes con alto riesgo de cáncer digestivo hereditario: documento de posicionamiento de la AEG, SEOM, AEGH y consorcio IMPaCT-GENÓMICA.

This position statement, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Oncología Médica, the Asociación Española de Genética Humana and the IMPaCT-Genómica Consortium aims to establish recommendations for use of multi-gene panel testing in patients at high risk of hereditary gastrointestinal and pancreatic cancer. To rate the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We reached a consensus among experts using a Delphi method. The document includes recommendations on clinical scenarios where multi-gene panel testing is recommended in colorectal cancer, polyposis syndromes, gastric and pancreatic cancer, as well as the genes to be considered in each clinical scenario. Recommendations on the evaluation of mosaicisms, counseling strategies in the absence of an index subject and, finally, constitutional analysis after identification of pathogenic tumor variants are also made.

Linked-color imaging versus high definition white-light endoscopy for evaluation of post-polypectomy scars of nonpedunculated lesions: LCI-Scar study.

BACKGROUND: Detection and treatment of recurrence after piecemeal endoscopic mucosal resection of nonpedunculated colorectal polyps are crucial for avoidance of post-colonoscopy cancer. Linked-color imaging (LCI) has demonstrated improved polyp detection but has never been assessed for evaluation of post-polypectomy scars. Our aim was to compare sensitivity and negative predictive value (NPV) between LCI and white-light endoscopy (WLE) for detection of post-polypectomy recurrence. METHODS: Patients undergoing surveillance colonoscopy after resection of lesions ≥15 mm were included in this prospective, single-center, randomized, crossover study. Each post-polypectomy scar underwent two examinations, one with LCI and the other with WLE, performed by two blinded endoscopists. Blue-light imaging (BLI) was then applied. A diagnosis of recurrence with a level of confidence was made for each modality and histopathology was the gold standard. RESULTS: 129 patients with 173 scars were included. Baseline patient, lesion, and procedural characteristics were similar in both arms. Recurrence was detected in 56/173 (32.4%), with 27/56 (48.2%) adenomas and 29/56 (51.8%) serrated lesions. LCI had greater sensitivity (96.4% [95%CI 87.8%-99.5%]) versus WLE (89.3% [95%CI 78.1%-95.9%]) and greater NPV (98.1% [95%CI 93.4%-99.8%] versus 94.6% [95%CI 88.7%-98.0%]). Paired concordance between modalities was 96.0%. In discordant cases, LCI identified four true-positive cases not detected by WLE and reclassified one false-positive of WLE. WLE reclassified two false positives of LCI without any increase in recurrence detection. CONCLUSIONS: LCI was highly accurate and had greater ability than WLE to rule out recurrence on post-polypectomy scars after resection of large polyps.

Serum DNA methylome of the colorectal cancer serrated pathway enables non-invasive detection.

The clinical relevance of the colorectal cancer serrated pathway is evident, but the screening of serrated lesions remains challenging. We aimed to characterize the serum methylome of the serrated pathway and to evaluate circulating cell-free DNA (cfDNA) methylomes as a potential source of biomarkers for the non-invasive detection of serrated lesions. We collected serum samples from individuals with serrated adenocarcinoma (SAC), traditional serrated adenomas, sessile serrated lesions, hyperplastic polyps and individuals with no colorectal findings. First, we quantified cfDNA methylation with the MethylationEPIC array. Then, we compared the methylation profiles with tissue and serum datasets. Finally, we evaluated the utility of serum cfDNA methylation biomarkers. We identified a differential methylation profile able to distinguish high-risk serrated lesions from no serrated neoplasia, showing concordance with tissue methylation from SAC and sessile serrated lesions. Serum methylation profiles are pathway-specific, clearly separating serrated lesions from conventional adenomas. The combination of ninjurin 2 (NINJ2) and glutamate-rich 1 (ERICH1) methylation discriminated high-risk serrated lesions and SAC with 91.4% sensitivity (64.4% specificity), while zinc finger protein 718 (ZNF718) methylation reported 100% sensitivity for the detection of SAC (96% specificity). This is the first study exploring the serum methylome of serrated lesions. Differential methylation of cfDNA can be used for the non-invasive detection of colorectal serrated lesions.

Cold snare polypectomy for duodenal adenomas in familial adenomatous polyposis: a prospective international cohort study.

Background and study aims In patients with familial adenomatous polyposis (FAP), endoscopic resection of duodenal adenomas is commonly performed to prevent cancer and prevent or defer duodenal surgery. However, based on studies using different resection techniques, adverse events (AEs) of polypectomy in the duodenum can be significant. We hypothesized that cold snare polypectomy (CSP) is a safe technique for duodenal adenomas in FAP and evaluated its outcomes in our centers. Patients and methods We performed a prospective international cohort study including FAP patients who underwent CSP for one or more superficial non-ampullary duodenal adenomas of any size between 2020 and 2022. At that time, this technique was common practice in our centers for superficial duodenal adenomas. The primary outcome was the occurrence of intraprocedural and post-procedural AEs. Results In total, 133 CSPs were performed in 39 patients with FAP (1-18 per session). Median adenoma size was 10 mm (interquartile range 8-15 mm), ranging from 5 to 40 mm; 27 adenomas were ≥20 mm (20%). Of the 133 polypectomies, 109 (82%) were performed after submucosal injection. Sixty-one adenomas (46%) were resected en bloc and 72 (54%) piecemeal. Macroscopic radical resection was achieved for 129 polypectomies (97%). Deep mural injury type II occurred in three polyps (2%) with no delayed perforation after prophylactic clipping. There were no clinically significant bleeds, perforations or other post-procedural AEs. Histopathology showed low-grade dysplasia in all 133 adenomas. Conclusions CSP for (multiple) superficial non-ampullary duodenal adenomas in FAP seems feasible and safe. Long-term prospective research is needed to evaluate whether protocolized duodenal polypectomies prevent cancer and surgery.

Quantification of rare somatic single nucleotide variants by droplet digital PCR using SuperSelective primers.

Somatic single-nucleotide variants (SNVs) occur every time a cell divides, appearing even in healthy tissues at low frequencies. These mutations may accumulate as neutral variants during aging, or eventually, promote the development of neoplasia. Here, we present the SP-ddPCR, a droplet digital PCR (ddPCR) based approach that utilizes customized SuperSelective primers aiming at quantifying the proportion of rare SNVs. For that purpose, we selected five potentially pathogenic variants identified by whole-exome sequencing (WES) occurring at low variant allele frequency (VAF) in at-risk colon healthy mucosa of patients diagnosed with colorectal cancer or advanced adenoma. Additionally, two APC SNVs detected in two cancer lesions were added to the study for WES-VAF validation. SuperSelective primers were designed to quantify SNVs at low VAFs both in silico and in clinical samples. In addition to the two APC SNVs in colonic lesions, SP-ddPCR confirmed the presence of three out of five selected SNVs in the normal colonic mucosa with allelic frequencies ≤ 5%. Moreover, SP-ddPCR showed the presence of two potentially pathogenic variants in the distal normal mucosa of patients with colorectal carcinoma. In summary, SP-ddPCR offers a rapid and feasible methodology to validate next-generation sequencing data and accurately quantify rare SNVs, thus providing a potential tool for diagnosis and stratification of at-risk patients based on their mutational profiling.

Exploring Stakeholders' Perspectives on Implementing Universal Germline Testing for Colorectal Cancer: Findings From a Clinical Practice Survey.

PURPOSE: New guidelines recommend considering germline genetic testing for all patients with colorectal cancer (CRC). However, there is a lack of data on stakeholders' perspectives on the advantages and barriers of implementing universal germline testing (UGT). This study assessed the perspectives of members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer (CGA-IGC) regarding the implementation of UGT for patients with CRC, including readiness, logistics, and barriers. METHODS: A cross-sectional survey was sent to 317 active members of CGA-IGC. The survey included sections on demographics, clinical practice specialty, established institutional practices for testing, and questions pertaining to support of and barriers to implementing UGT for patients with CRC. RESULTS: Eighty CGA-IGC members (25%) participated, including 42 genetic counselors (53%) and 14 gastroenterologists (18%). Forty-seven (59%) reported an academic medical center as their primary work setting, and most participants (56%) had more than 10 years of clinical practice. Although most participants (73%) supported UGT, 54% indicated that changes in practice would be required before adopting UGT, and 39% indicated that these changes would be challenging to implement. There was support for both genetics and nongenetics providers to order genetic testing, and a majority (57%) supported a standardized multigene panel rather than a customized gene panel. Key barriers to UGT implementation included limited genetics knowledge among nongenetics providers, time-consuming processes for obtaining consent, ordering tests, disclosing results, and lack of insurance coverage. CONCLUSION: This study demonstrates wide support among hereditary GI cancer experts for implementation of UGT for patients with CRC. However, alternative service delivery models using nongenetics providers should be considered to address the logistical barriers to UGT implementation, particularly the growing demand for genetic testing.

Serum methylation of GALNT9, UPF3A, WARS, and LDB2 as noninvasive biomarkers for the early detection of colorectal cancer and advanced adenomas.

BACKGROUND: Early detection has proven to be the most effective strategy to reduce the incidence and mortality of colorectal cancer (CRC). Nevertheless, most current screening programs suffer from low participation rates. A blood test may improve both the adherence to screening and the selection to colonoscopy. In this study, we conducted a serum-based discovery and validation of cfDNA methylation biomarkers for CRC screening in a multicenter cohort of 433 serum samples including healthy controls, benign pathologies, advanced adenomas (AA), and CRC. RESULTS: First, we performed an epigenome-wide methylation analysis with the MethylationEPIC array using a sample pooling approach, followed by a robust prioritization of candidate biomarkers for the detection of advanced neoplasia (AN: AA and CRC). Then, candidate biomarkers were validated by pyrosequencing in independent individual cfDNA samples. We report GALNT9, UPF3A, WARS, and LDB2 as new noninvasive biomarkers for the early detection of AN. The combination of GALNT9/UPF3A by logistic regression discriminated AN with 78.8% sensitivity and 100% specificity, outperforming the commonly used fecal immunochemical test and the methylated SEPT9 blood test. CONCLUSIONS: Overall, this study highlights the utility of cfDNA methylation for CRC screening. Our results suggest that the combination methylated GALNT9/UPF3A has the potential to serve as a highly specific and sensitive blood-based test for screening and early detection of CRC.

Screening uptake of colonoscopy versus fecal immunochemical testing in first-degree relatives of patients with non-syndromic colorectal cancer: A multicenter, open-label, parallel-group, randomized trial (ParCoFit study).

BACKGROUND: Colonoscopy screening is underused by first-degree relatives (FDRs) of patients with non-syndromic colorectal cancer (CRC) with screening completion rates below 50%. Studies conducted in FDR referred for screening suggest that fecal immunochemical testing (FIT) was not inferior to colonoscopy in terms of diagnostic yield and tumor staging, but screening uptake of FIT has not yet been tested in this population. In this study, we investigated whether the uptake of FIT screening is superior to the uptake of colonoscopy screening in the familial-risk population, with an equivalent effect on CRC detection. METHODS AND FINDINGS: This open-label, parallel-group, randomized trial was conducted in 12 Spanish centers between February 2016 and December 2021. Eligible individuals included asymptomatic FDR of index cases <60 years, siblings or ≥2 FDR with CRC. The primary outcome was to compare screening uptake between colonoscopy and FIT. The secondary outcome was to determine the efficacy of each strategy to detect advanced colorectal neoplasia (adenoma or serrated polyps ≥10 mm, polyps with tubulovillous architecture, high-grade dysplasia, and/or CRC). Screening-naïve FDR were randomized (1:1) to one-time colonoscopy versus annual FIT during 3 consecutive years followed by a work-up colonoscopy in the case of a positive test. Randomization was performed before signing the informed consent using computer-generated allocation algorithm based on stratified block randomization. Multivariable regression analysis was performed by intention-to-screen. On December 31, 2019, when 81% of the estimated sample size was reached, the trial was terminated prematurely after an interim analysis for futility. Study outcomes were further analyzed through 2-year follow-up. The main limitation of this study was the impossibility of collecting information on eligible individuals who declined to participate. A total of 1,790 FDR of 460 index cases were evaluated for inclusion, of whom 870 were assigned to undergo one-time colonoscopy (n = 431) or FIT (n = 439). Of them, 383 (44.0%) attended the appointment and signed the informed consent: 147/431 (34.1%) FDR received colonoscopy-based screening and 158/439 (35.9%) underwent FIT-based screening (odds ratio [OR] 1.08; 95% confidence intervals [CI] [0.82, 1.44], p = 0.564). The detection rate of advanced colorectal neoplasia was significantly higher in the colonoscopy group than in the FIT group (OR 3.64, 95% CI [1.55, 8.53], p = 0.003). Study outcomes did not change throughout follow-up. CONCLUSIONS: In this study, compared to colonoscopy, FIT screening did not improve screening uptake by individuals at high risk of CRC, resulting in less detection of advanced colorectal neoplasia. Further studies are needed to assess how screening uptake could be improved in this high-risk group, including by inclusion in population-based screening programs. TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov (NCT02567045).

Fecal occult blood and calprotectin testing to prioritize primary care patients for colonoscopy referral: The advantage study.

BACKGROUND: Colonoscopy is the gold standard for colorectal cancer (CRC) diagnosis and screening, but endoscopy services are usually overburdened. This study aims to investigate the usefulness of fecal hemoglobin (fHb) and calprotectin (FC) for the identification of patients with high probability of CRC who need urgent referral. METHODS: In a multicenter prospective study, we enrolled symptomatic patients referred from primary care for colonoscopy. Prior to bowel preparation, fHb and FC quantitative tests were performed. The diagnostic performance was estimated for each biomarker/combination. We built a multivariable predictive model based on logistic regression, translated to a nomogram and a risk calculator to assist clinicians in the decision-making process. RESULTS: The study included 1224 patients, of whom 69 (5.6%) had CRC. At the fHb cut-offs of >0 and 10 µg/g, the negative predictive values for CRC were 98.8% (95% confidence interval 97.8%-99.3%) and 98.6% (95%CI 97.7%-99.1%), and the sensitivities were 85.5% (95%CI 75.0%-92.8%) and 79.7% (95%CI 68.3%-88.4%), respectively. When we added the cut-off of 150 µg/g of FC to both fHb thresholds, the sensitivity of fecal tests improved. In the multivariate logistic regression model, the concentration of fHb was an independent predictor for CRC; age and gender were also independently associated with CRC. CONCLUSIONS: fHb and FC are useful as part of a triage tool to identify those symptomatic patients with high probability of CRC. This can be easily applied by physicians to prioritize high-risk patients for urgent colonoscopy.

Current chemoprevention approaches in Lynch syndrome and Familial adenomatous polyposis: a global clinical practice survey.

Background: International chemoprevention preferences and approaches in Lynch syndrome (LS) and APC-associated polyposis, including Familial adenomatous polyposis (FAP) and attenuated FAP (AFAP) have not been previously explored. Aim: To describe current chemoprevention strategies for patients with LS or FAP/AFAP (referred to collectively as FAP) practiced by members of four international hereditary cancer societies through administration of a survey. Results: Ninety-six participants across four hereditary gastrointestinal cancer societies responded to the survey. Most respondents (91%, 87/96) completed information regarding their demographics and practice characteristics relating to hereditary gastrointestinal cancer and chemoprevention clinical practices. Sixty-nine percent (60/87) of respondents offer chemoprevention for FAP and/or LS as a part of their practice. Of the 75% (72/96) of survey respondents who were eligible to answer practice-based clinical vignettes based off of their responses to ten barrier questions regarding chemoprevention, 88% (63/72) of those participants completed at least one case vignette question to further characterize chemoprevention practices in FAP and/or LS. In FAP, 51% (32/63) would offer chemoprevention for rectal polyposis, with sulindac - 300 mg (18%, 10/56) and aspirin (16%, 9/56) being the most frequently selected options. In LS, 93% (55/59) of professionals discuss chemoprevention and 59% (35/59) frequently recommend chemoprevention. Close to half of the respondents (47%, 26/55) would recommend beginning aspirin at time of commencement of the patient's first screening colonoscopy (usually at age 25yrs). Ninety-four percent (47/50) of respondents would consider a patient's diagnosis of LS as an influential factor for aspirin use. There was no consensus on the dose of aspirin (≤100 mg, >100 mg - 325 mg or 600 mg) to offer patients with LS and there was no agreement on how other factors, such as BMI, hypertension, family history of colorectal cancer, and family history of heart disease, would affect the recommendation for aspirin use. Possible harm among older patients (>70 years) was identified as the most common reason to discourage aspirin use. Conclusion: Although chemoprevention is widely discussed and offered to patients with FAP and LS by an international group of hereditary gastrointestinal cancer experts, there is significant heterogeneity in how it is applied in clinical practice.

Mortality by age, gene and gender in carriers of pathogenic mismatch repair gene variants receiving surveillance for early cancer diagnosis and treatment: a report from the prospective Lynch syndrome database.

Background: The Prospective Lynch Syndrome Database (PLSD) collates information on carriers of pathogenic or likely pathogenic MMR variants (path_MMR) who are receiving medical follow-up, including colonoscopy surveillance, which aims to the achieve early diagnosis and treatment of cancers. Here we use the most recent PLSD cohort that is larger and has wider geographical representation than previous versions, allowing us to present mortality as an outcome, and median ages at cancer diagnoses for the first time. Methods: The PLSD is a prospective observational study without a control group that was designed in 2012 and updated up to October 2022. Data for 8500 carriers of path_MMR variants from 25 countries were included, providing 71,713 years of follow up. Cumulative cancer incidences at 65 years of age were combined with 10-year crude survival following cancer, to derive estimates of mortality up to 75 years of age by organ, gene, and gender. Findings: Gynaecological cancers were more frequent than colorectal cancers in path_MSH2, path_MSH6 and path_PMS2 carriers [cumulative incidence: 53.3%, 49.6% and 23.3% at 75 years, respectively]. Endometrial, colon and ovarian cancer had low mortality [8%, 13% and 15%, respectively] and prostate cancers were frequent in male path_MSH2 carriers [cumulative incidence: 39.7% at 75 years]. Pancreatic, brain, biliary tract and ureter and kidney and urinary bladder cancers were associated with high mortality [83%, 66%, 58%, 27%, and 29%, respectively]. Among path_MMR carriers undergoing colonoscopy surveillance, particularly path_MSH2 carriers, more deaths followed non-colorectal Lynch syndrome cancers than colorectal cancers. Interpretation: In path_MMR carriers undergoing colonoscopy surveillance, non-colorectal Lynch syndrome cancers were associated with more deaths than were colorectal cancers. Reducing deaths from non-colorectal cancers presents a key challenge in contemporary medical care in Lynch syndrome. Funding: We acknowledge funding from the Norwegian Cancer Society, contract 194751-2017.

Personalized endoscopic surveillance and intervention protocols for patients with familial adenomatous polyposis: the European FAP Consortium strategy.

Background and study aims Patients with familial adenomatous polyposis (FAP) undergo colectomy and lifelong endoscopic surveillance to prevent colorectal, duodenal and gastric cancer. Endoscopy has advanced significantly in recent years, including both detection technology as well as treatment options. For the lower gastrointestinal tract, current guidelines do not provide clear recommendations for surveillance intervals. Furthermore, the Spigelman staging system for duodenal polyposis has its limitations. We present a newly developed personalized endoscopic surveillance strategy for the lower and upper gastrointestinal tract, aiming to improve the care for patients with FAP. We aim to inform centers caring for FAP patients and encourage the discussion on optimizing endoscopic surveillance and treatment in this high-risk population. Methods The European FAP Consortium, consisting of endoscopists with expertise in FAP, collaboratively developed new surveillance protocols. The proposed strategy was consensus-based and a result of several consortium meetings, discussing current evidence and limitations of existing systems. This strategy provides clear indications for endoscopic polypectomy in the rectum, pouch, duodenum and stomach and defines new criteria for surveillance intervals. This strategy will be evaluated in a 5-year prospective study in nine FAP expert centers in Europe. Results We present a newly developed personalized endoscopic surveillance and endoscopic treatment strategy for patients with FAP aiming to prevent cancer, optimize endoscopic resources and limit the number of surgical interventions. Following this new strategy, prospectively collected data in a large cohort of patients will inform us on the efficacy and safety of the proposed approaches.

BMPR2 as a Novel Predisposition Gene for Hereditary Colorectal Polyposis.

BACKGROUND & AIMS: Colorectal cancer (CRC) is one of the most prevalent tumors worldwide, with incidence quickly increasing (particularly in the context of early-onset cases), despite important prevention efforts, mainly in the form of population-wide screening programs. Although many cases present a clear familial component, the current list of hereditary CRC genes leaves a considerable proportion of the cases unexplained. METHODS: In this work, we used whole-exome sequencing approaches on 19 unrelated patients with unexplained colonic polyposis to identify candidate CRC predisposition genes. The candidate genes were then validated in an additional series of 365 patients. CRISPR-Cas9 models were used to validate BMPR2 as a potential candidate for CRC risk. RESULTS: We found 8 individuals carrying 6 different variants in the BMPR2 gene (approximately 2% of our cohort of patients with unexplained colonic polyposis). CRISPR-Cas9 models of 3 of these variants showed that the p.(Asn442Thrfs∗32) truncating variant completely abrogated BMP pathway function in a similar way to the BMPR2 knockout. Missense variants p.(Asn565Ser), p.(Ser967Pro) had varying effects on cell proliferation levels, with the former impairing cell control inhibition via noncanonical pathways. CONCLUSIONS: Collectively, these results support loss-of-function BMPR2 variants as candidates to be involved in CRC germline predisposition.

Pancreatic Cancer Surveillance in Carriers of a Germline Pathogenic Variant in CDKN2A.

Three percent of patients with pancreatic ductal adenocarcinoma (PDAC) present a germline pathogenic variant (GPV) associated with an increased risk of this tumor, CDKN2A being one of the genes associated with the highest risk. There is no clear consensus on the recommendations for surveillance in CDKN2A GPV carriers, although the latest guidelines from the International Cancer of the Pancreas Screening Consortium recommend annual endoscopic ultrasound (EUS) or magnetic resonance imaging (MRI) regardless of family history. Our aim is to describe the findings of the PDAC surveillance program in a cohort of healthy CDKN2A GPV heterozygotes. This is an observational analysis of prospectively collected data from all CDKN2A carriers who underwent screening for PDAC at the high-risk digestive cancer clinic of the "Hospital Clínic de Barcelona" between 2013 and 2021. A total of 78 subjects were included. EUS or MRI was performed annually with a median follow-up of 66 months. Up to 17 pancreatic findings were described in 16 (20.5%) individuals under surveillance, although most of them were benign. No significant precursor lesions were identified, but an early PDAC was detected and treated. While better preventive strategies are developed, we believe that annual surveillance with EUS and/or MRI in CDKN2A GPV heterozygotes may be beneficial.

Unraveling the impact of a germline heterozygous POLD1 frameshift variant in serrated polyposis syndrome.

Serrated polyposis syndrome (SPS) is one of the most frequent polyposis syndromes characterized by an increased risk for developing colorectal cancer (CRC). Although SPS etiology has been mainly associated with environmental factors, germline predisposition to SPS could also be relevant for cases with familial aggregation or a family history of SPS/CRC. After whole-exome sequencing of 39 SPS patients from 16 families, we identified a heterozygous germline frameshift variant in the POLD1 gene (c.1941delG, p.(Lys648fs*46)) in a patient with SPS and CRC. Tumor presented an ultra-hypermutated phenotype and microsatellite instability. The POLD1 germline variant segregated in three additional SPS-affected family members. We attempted to create yeast and cellular models for this variant but were no viable. Alternatively, we generated patient-derived organoids (PDOs) from healthy rectal tissue of the index case, as well as from a control donor. Then, we challenged PDOs with a DNA-damaging agent to induce replication stress. No significant differences were observed in the DNA damage response between control and POLD1-Lys648fs PDOs, nor specific mutational signatures were observed. Our results do not support the pathogenicity of the analyzed POLD1 frameshift variant. One possible explanation is that haplosufficiency of the wild-type allele may be compensating for the absence of expression of the frameshift allele. Overall, future work is required to elucidate if functional consequences could be derived from POLD1 alterations different from missense variants in their proofreading domain. To our knowledge, our study presents the first organoid model for germline POLD1 variants and establishes the basis for its use as a model for disease in SPS, CRC and other malignancies.

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.

Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines.

BACKGROUND & AIMS: Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC. METHODS: After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%. RESULTS: The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients. CONCLUSIONS: The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC.