CD31-positive microvessel density within adenomas of Lynch Syndrome patients is similar compared to adenomas of non-Lynch patients

Effect of genetic profiling on surgical decisions at hereditary colorectal cancer syndromes

Hereditary colorectal cancer syndromes, such as Lynch syndrome and familial adenomatous polyposis (FAP), present significant clinical challenges due to the heightened cancer risks associated with these genetic conditions. This review explores genetic profiling impact on surgical decisions for hereditary colorectal cancer (HCRC), assessing options, timing, and outcomes. Genotypes of different HCRCs are discussed, revealing a connection between genetic profiles, disease severity, and outcomes. For Lynch syndrome, mutations in the MLH1, MSH2, MSH6, and PMS2 genes guide the choice of surgery. Subtotal colectomy is recommended for patients with mutations in MLH1 and MSH2, while segmental colectomy is preferred for those with MSH6 and PMS2 mutations. In cases of metachronous colon cancer after segmental colectomy, subtotal colectomy with ileorectal anastomosis is advised for all mutations. Surgical strategies for primary rectal cancer include anterior resection or abdominoperineal resection (APR), irrespective of the specific mutation. For rectal cancer occurring after a previous segmental colectomy, proctocolectomy with ileal pouch-anal anastomosis (IPAA) or APR with a permanent ileostomy is recommended. In FAP, surgical decisions are based on genotype-phenotype correlations. The risk of desmoid tumors post-surgery supports a single-stage approach, particularly for certain APC gene variants. Juvenile Polyposis Syndrome (JPS) surgical decisions involve genetic testing, polyp characteristics with attention to vascular lesions in SMAD4 mutation carriers. However, genetic profiling does not directly dictate the specific surgical approach for JPS. In conclusion this review highlights the critical role of personalized surgical plans based on genetic profiles to optimize patient outcomes and reduce cancer risk. Further research is needed to refine these strategies and enhance clinical guidelines.

Risk-stratified faecal immunochemical testing (FIT) for urgent colonoscopy in Lynch syndrome during the COVID-19 pandemic

BACKGROUND

Lynch syndrome is a hereditary cancer disease resulting in an increased risk of colorectal cancer. Herein, findings are reported from an emergency clinical service implemented during the COVID-19 pandemic utilizing faecal immunochemical testing ('FIT') in Lynch syndrome patients to prioritize colonoscopy while endoscopy services were limited.

METHODS

An emergency service protocol was designed to improve colonoscopic surveillance access throughout the COVID-19 pandemic in England for people with Lynch syndrome when services were extremely restricted (1 March 2020 to 31 March 2021) and promoted by the English National Health Service. Requests for faecal immunochemical testing from participating centres were sent to the National Health Service Bowel Cancer Screening South of England Hub and a faecal immunochemical testing kit, faecal immunochemical testing instructions, paper-based survey, and pre-paid return envelope were sent to patients. Reports with faecal haemoglobin results were returned electronically for clinical action. Risk stratification for colonoscopy was as follows: faecal haemoglobin less than 10 µg of haemoglobin/g of faeces (µg/g)-scheduled within 6-12 weeks; and faecal haemoglobin greater than or equal to 10 µg/g-triaged via an urgent suspected cancer clinical pathway. Primary outcomes of interest included the identification of highest-risk Lynch syndrome patients and determining the impact of faecal immunochemical testing in risk-stratified colonoscopic surveillance.

RESULTS

Fifteen centres participated from June 2020 to March 2021. Uptake was 68.8 per cent amongst 558 patients invited. For 339 eligible participants analysed, 279 (82.3 per cent) had faecal haemoglobin less than 10 µg/g and 60 (17.7 per cent) had faecal haemoglobin greater than or equal to 10 µg/g. In the latter group, the diagnostic accuracy of faecal immunochemical testing was 65.9 per cent and escalation to colonoscopy was facilitated (median 49 versus 122 days, χ2 = 0.0003, P < 0.001).

CONCLUSION

Faecal immunochemical testing demonstrated clinical value for Lynch syndrome patients requiring colorectal cancer surveillance during the pandemic in this descriptive report of an emergency COVID-19 response service. Further longitudinal investigation on faecal immunochemical testing efficacy in Lynch syndrome is warranted and will be examined under the 'FIT for Lynch' study (ISRCTN15740250).

Real-time diagnostic accuracy of blue light imaging, linked color imaging and white-light endoscopy for colorectal polyp characterization

Background and study aims  Fujifilm has developed a novel ELUXEO 7000 endoscope system that employs light-emitting diodes (LEDs) at four different wavelengths as light sources that enable blue light imaging (BLI), linked color imaging (LCI), and high-definition white-light endoscopy (HD-WLE). The aim of this study was to address the diagnostic accuracy of real-time polyp characterization using BLI, LCI and HD-WLE (ELUXEO 7000 endoscopy system). Patients methods  This is a prespecified post-hoc analysis of a prospective study in which 22 experienced endoscopists (> 2,000 colonoscopies) from eight international centers participated. Using a combination of BLI, LCI, and HD-WLE, lesions were endoscopically characterized including a high- or low-confidence statement. Per protocol, digital images were created from all three imaging modalities. Histopathology was the reference standard. Endoscopists were familiar with polyp characterization, but did not take dedicated training for purposes of this study. Results  Overall, 341 lesions were detected in 332 patients. Of the lesions, 269 histologically confirmed polyps with an optical diagnosis were included for analysis (165 adenomas, 27 sessile serrated lesions, and 77 hyperplastic polyps). Overall, polyp characterization was performed with high confidence in 82.9 %. The overall accuracy for polyp characterization was 75.1 % (95 % confidence interval [CI] 69.5-80.1 %), compared with an accuracy of 78.0 % (95 % CI 72.0-83.2 %) for high confidence assignments. The accuracy for endoscopic characterization for diminutive polyps was 74.7 % (95 %CI 68.4-80.3 %), compared with an accuracy of 78.2 % (95 % CI 71.4-84.0 %) for high-confidence assignments. Conclusions  The diagnostic accuracy of BLI, LCI, and HD-WLE by experienced endoscopist for real-time polyp characterization seems limited (NCT03344289).

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.