Molecular Features of the Serrated Pathway to Colorectal Cancer: Current Knowledge and Future Directions

Serrated lesions are the precursor lesions of a new model of colorectal carcinogenesis. From a molecular standpoint, the serrated pathway is thought to be responsible for up to 30% of all colorectal cancer cases. The three major processes of this molecular mechanism are alterations in the mitogen-activated protein kinase pathway, production of the CpG island methylation phenotype, and generation of microsatellite instability. Other contributing processes are activation of WNT, alterations in the regulation of tumor suppressor genes, and alterations in microRNAs or in MUC5AC hypomethylation. Although alterations in the serrated pathway also contribute, their precise roles remain obscure because of the various methodologies and definitions used by different research groups. This knowledge gap affects clinical assessment of precursor lesions for their carcinogenic risk. The present review describes the current literature reporting the molecular mechanisms underlying each type of serrated lesion and each phenotype of serrated pathway colorectal cancer, identifying those areas that merit additional research. We also propose a unified serrated carcinogenesis pathway combining molecular alterations and types of serrated lesions, which ends in different serrated pathway colorectal cancer phenotypes depending on the route followed. Finally, we describe some key issues that need to be addressed in order to incorporate the newest technologies in serrated pathway research and to improve overall knowledge for developing specific prevention strategies and new therapeutic targets

Endoscopic resection of colorectal polyps in patients on antiplatelet therapy: an evidence-based guidance for clinicians

Due to the rising prevalence of coronary heart disease, endoscopists are more frequently performing a polypectomy in patients on antiplatelet therapy (APT) and dual antiplatelet therapy (DATP). Despite the availability of several guidelines with regard to the management of antiplatelet drugs during the periprocedure period, there is still variability in the current clinical practice. This may be influenced by the low quality of the evidence supporting recommendations, because most of the studies dealing with APT and polypectomy are observational and retrospective, and include mainly small (< 10 mm) polyps. However, some recommendations can still be made. An estimation of the bleeding and thrombotic risk of the patient should be made in advance. In the case of DAPT the procedure should be postponed, at least until clopidogrel can be safely withheld. If possible, non-aspirin antiplatelet drugs should be withheld 5-7 days before the procedure. Polyp size is the main factor related with post-polypectomy bleeding and it is the factor that should drive clinical decisions regarding the resection method and the use of endoscopic prophylactic measures. Non-aspirin antiplatelet agents can be reintroduced 24-48 hours after the procedure. In conclusion, there is little data with regard to the management of DAPT in patients with a scheduled polypectomy. Large randomized controlled trials are needed to support clinical recommendations

Early colorectal cancer diagnosed after endoscopic resection: Conservative treatment is safe in most of the cases. Proposal for a risk-based management

Endoscopic resection offers advantages over surgical resection for early colorectal cancer (ECC). However, there might be a presumed risk of recurrence. We aimed to determine the risk of recurrence after endoscopic removal of ECC

Insertion of self-expanding metal stent for treatment of malignant obstruction in a pregnant woman

Colorectal cancer (CRC) is the second most frequent cancer both in incidence and mortality in women, especially in those over 60 years of age. Diagnosis in women at gestational age is rare, so its incidence during pregnancy is low. However, an increase in its diagnosis is expected during the next years because of the raise in the average age of pregnancy. In most cases, the diagnosis is delayed because symptoms related to CRC can be attributed to pregnancy itself. Up to 30 % of CRC cases may present as an intestinal obstruction. In this situation, the main objective is to solve the clinical emergency in the safest way for mother and fetus, together with performing an accurate diagnostic approach to offer the best possible therapeutic management knowing the limitations and difficulties related to pregnancy. The self-expanding metallic stent (SEMS) can be particularly useful in colon obstruction in a pregnant patient with CRC because it allows solving the acute condition providing time to perform a more accurate staging study and to prepare the patient for surgery, thus reducing both post-surgical morbidity and mortality. We report on the case of a patient who early in the second trimester of pregnancy presented with an acute colonic obstruction due to CRC which was successfully managed with the placement of a self-expanding metal stent

Curriculum for optical diagnosis training in Europe: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Main Recommendations This manuscript represents an official Position Statement of the European Society of Gastrointestinal Endoscopy (ESGE) aiming to guide general gastroenterologists to develop and maintain skills in optical diagnosis during endoscopy. In general, this requires additional training beyond the core curriculum currently provided in each country. In this context, ESGE have developed a European core curriculum for optical diagnosis practice across Europe for high quality optical diagnosis training. 1 ESGE suggests that every endoscopist should have achieved general competence in upper and/or lower gastrointestinal (UGI/LGI) endoscopy before commencing training in optical diagnosis of the UGI/LGI tract, meaning personal experience of at least 300 UGI and/or 300 LGI endoscopies and meeting the ESGE quality measures for UGI/LGI endoscopy. ESGE suggests that every endoscopist should be able and competent to perform UGI/LGI endoscopy with high definition white light combined with virtual and/or dye-based chromoendoscopy before commencing training in optical diagnosis. 2 ESGE suggests competency in optical diagnosis can be learned by attending a validated optical diagnosis training course based on a validated classification, and self-learning with a minimum number of lesions. If no validated training course is available, optical diagnosis can only be learned by attending a non-validated onsite training course and self-learning with a minimum number of lesions. 3 ESGE suggests endoscopists are competent in optical diagnosis after meeting the pre-adoption and learning criteria, and meeting competence thresholds by assessing a minimum number of lesions prospectively during real-time endoscopy. ESGE suggests ongoing in vivo practice by endoscopists to maintain competence in optical diagnosis. If a competent endoscopist does not perform in vivo optical diagnosis on a regular basis, ESGE suggests repeating the learning and competence phases to maintain competence. Key areas of interest were optical diagnosis training in Barrett's esophagus, esophageal squamous cell carcinoma, early gastric cancer, diminutive colorectal lesions, early colorectal cancer, and neoplasia in inflammatory bowel disease. Condition-specific recommendations are provided in the main document