The absolute number of small and diminutive adenomas with high-grade dysplasia is substantially higher compared with large adenomas: a retrospective pooled study.

Introduction: The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population. Methods: The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category. Results: Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size. Conclusions: Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer. Systematic Review Registration: http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

Feeding responses of reef-building corals provide species- and concentration-dependent risk assessment of microplastic.

The negative impacts of microplastic on reef-building corals are often attributed to the feeding responses to these particles. Although reactions to and ingestion of microplastic are frequently reported, a quantitative comparison to natural particles and of the factors influencing these responses is largely missing. Thus, this study aims to compare the feeding rates of corals to microplastic and natural particles, considering factors influencing these responses. Specifically, we I) studied the feeding responses of corals to microplastic, natural food, and non-food particles, II) examined the influence of biotic factors (i.e., biofilm on the particles and presence of natural food), III) evaluated species-specific differences in feeding responses to microplastic particles, and IV) applied a toxicodynamic model for species- and concentration-dependent risk assessments. We assessed the feeding responses of 11 coral species, spanning different life-history strategies and growth forms in experimental feeding trials. The results showed that the feeding responses of corals to microplastic differ from those to naturally occurring particles. Reactions to microplastic and natural food occurred equally often, while sand was more frequently rejected. Yet, the ingestion process was much more selective, and microplastic was ingested less frequently than natural food. The presence of a biofilm and natural food had activating effects on the feeding behavior of the corals on microplastic. Generally, coral species that exhibit a higher degree of heterotrophic feeding also reacted more often to microplastic. The species- and concentration-dependent toxicodynamic risk model built on these data reveals that most tested coral species are unlikely to be at risk under present environmental concentration levels. However, highly heterotrophic feeders, such as Blastomussa merleti, or generally vulnerable species, such as Pocillopora verrucosa, need special consideration. These findings help to better evaluate the responses of corals to microplastic and their risk in an increasingly polluted ocean.

Best Practices for Resection of Diminutive and Small Polyps in the Colorectum.

Diminutive colorectal lesions are polyps and flat lesions 1 to 5 mm in size, and small are 6 to 9 mm in size. The best resection method is the cold snare. Cold forceps are acceptable for 1- to 3-mm lesions, but should not be used to piecemeal polyps. Cold snaring has few complications and is more effective than cold forceps for 4- to 5-mm polyps and as effective and more efficient than hot snaring for 6- to 9-mm polyps.

Challenges associated with the pathological diagnosis of colorectal tumors less than 10 mm in size.

Various techniques including cold snare polypectomy and endoscopic mucosal resection are used for the removal of small colorectal polyps. Specimens of resected polyps are prepared in pathology laboratories and analyzed to make a pathological diagnosis. However, reports on how different resection methods influence the pathological diagnosis are limited. This article discusses the problems associated with the failure of polyp retrieval and fragmentation of small specimens during collection and the effects of certain parameters on the pathological diagnosis, particularly with regard to surgical margins. In the future, although pathologists are expected to encounter problems as a result of minor findings that are not clinically problematic, relatively rare cases such as submucosal invasion by a small carcinoma should not be overlooked.

Responses of reef building corals to microplastic exposure.

Pollution of marine environments with microplastic particles (i.e. plastic fragments <5 mm) has increased rapidly during the last decades. As these particles are mainly of terrestrial origin, coastal ecosystems such as coral reefs are particularly threatened. Recent studies revealed that microplastic ingestion can have adverse effects on marine invertebrates. However, little is known about its effects on small-polyp stony corals that are the main framework builders in coral reefs. The goal of this study is to characterise how different coral species I) respond to microplastic particles and whether the exposure might II) lead to health effects. Therefore, six small-polyp stony coral species belonging to the genera Acropora, Pocillopora, and Porites were exposed to microplastics (polyethylene, size 37-163 µm, concentration ca. 4000 particles L-1) over four weeks, and responses and effects on health were documented. The study showed that the corals responded differentially to microplastics. Cleaning mechanisms (direct interaction, mucus production) but also feeding interactions (i.e. interaction with mesenterial filaments, ingestion, and egestion) were observed. Additionally, passive contact through overgrowth was documented. In five of the six studied species, negative effects on health (i.e. bleaching and tissue necrosis) were reported. We here provide preliminary knowledge about coral-microplastic-interactions. The results call for further investigations of the effects of realistic microplastic concentrations on growth, reproduction, and survival of stony corals. This might lead to a better understanding of resilience capacities in coral reef ecosystems.

Cold snare polypectomy: does snare type influence outcomes?

BACKGROUND AND AIM: Cold snare techniques are widely used for the removal of small and diminutive polyps. The influence of snare type on the effectiveness of cold snare polypectomy is unknown. METHODS: Cold snare polypectomy of 3-7-mm polyps was undertaken using either a thin wire mini-snare (0.30 mm) or a thick wire mini-snare (0.47 mm). Primary outcome was endoscopic completeness of excision. Consensus regarding endoscopic assessment of completeness of excision was standardized and aided by chromoendoscopy. Secondary outcomes included: completeness of histological excision, polyp 'fly away', polyp retrieval rate, early or delayed bleeding and perforation. RESULTS: One hundred and fifty-seven polyps were removed ranging from 3 to 7 mm, 62% were situated in the left side of the colon and 89.4% were sessile. Endoscopic completeness of excision was significantly higher with the thin wire snare compared to the thick wire snare (90.2% vs 73.3%, P < 0.05). There was a numerical trend towards a higher complete histological excision rate with the thin wire snare, but this did not reach statistical significance (73.3% vs 65.2%, P = 0.4). There was a fair level of agreement (kappa = 0.36) between endoscopic and histological completeness of excision. Polyp 'fly away' occurred less often with the thin wire snare (14.6% vs 35.3%, P = 0.002), but there was no significant difference in polyp retrieval rate (84.3% vs 83.8%, P = 0.94). There were no complications with either snare. CONCLUSION: Snare type appears to be an important determinant of completeness of excision when removing small polyps by the cold snare technique.

Cold snare polypectomy with pull technique of flat colonic polyps up to 12 mm: a porcine model.

BACKGROUND: Most colonoscopic complications are polypectomy-related and occur more frequently during the removal of numerous small polyps. Therefore, it is important to have the best polypectomy approach of small polyps. The aim of the present animal study was to investigate the effectiveness and safety of cold snare polypectomy (CSP) technique combined with light pull of the snare in order to peel the mucosal and upper submucosal layer, namely pull CSP (PCSP), for the removal of polyps sized up to 12 mm in porcine models. METHODS: We performed a series of polypectomies in the pig colon with a double-channel experimental gastroscope using PCSP technique. RESULTS: Thirty cases of "polyps" larger than 7 mm and up to 12 mm were treated using PCSP technique. No sign of perforation or bleeding was observed in all cases performed with PCSP. CONCLUSIONS: According to our preliminary results in this animal model, PCSP could be a safe and effective technique for flat colonic polyp removal up to 12 mm in size consistent with the basic polypectomy principles.