Factors associated with positive predictive value of preliminary screening in a two-step screening strategy for colorectal neoplasms in China

Background The positive predictive value (PPV) of high risk factor questionnaire (HRFQ) plus fecal immunochemical test (FIT) as preliminary screening strategy for colorectal-related neoplasia is relatively low. We aim to explore independent factors associated with PPVs of HRFQ combined FIT for selecting high risk individuals for colonoscopy. Methods A total of 6971 residents were enrolled in a community-based screening program. Participants who had positive results of HRFQ and/or FIT and subsequently received colonoscopy were involved. The associations of socio-demographic factors, lifestyle behaviors, and high risk factors of colorectal cancer with PPVs of HRFQ, FIT, and their combination were evaluated by multivariable logistic regression models. Results Among 572 involved cases, 249 (43.5%) colorectal neoplasms were detected by colonoscopy, including 71 advanced adenoma (12.4%) and 9 colorectal cancer (CRC) (1.6%). The PPVs of preliminary screening were 43.5% for total colorectal neoplasms, 14.0% for advanced neoplasm, and 1.6% for CRC. Adding positive HRFQ to FIT could improve the PPV from 3.5 to 8.0% for detecting CRC. Preliminarily screened positive individuals who were males [adjusted odds ratio (AOR): 1.95, 95% CI 1.31, 2.90; p < 0.001], elders (> 60 years) (AOR: 1.70, 95% CI 1.17, 2.46; p = 0.005), or ex-/current smokers (AOR: 3.04, 95% CI 1.31, 7.09; p = 0.10) had higher odds of PPVs of detecting colorectal neoplasms. Conclusions Combining HRFQ and FIT could largely improve PPVs for screening advanced neoplasm and CRC. Gender and age-specific FIT cut-off values as well as initiating ages for CRC screening might be recommended to improve the accuracy and effectiveness of current screening algorithm.

The Importance of CT Pneumocolon in Detecting Colonic Lesions

Background: Colonic masses are clinically important because some of them are malignant and others have a tendency to become malignant such as polyps. CT pneumocolon may have a role in the evaluation and diagnosis of these masses. Objective: To determine the accuracy of computed tomography (CT) pmeumocolon in the detection of colonic masses compared with colonoscopy. Patients and Methods: A total of 60 patients with colorectal symptoms underwent evaluation for the presence of colorectal neoplasms by using both colonoscopy and CT pneumocolon and a comparison was made between them. Results: On colonoscopy, 10 out of 60 patients were having a negative colonoscopy. The results of colonoscopy of the other 50 patients were as follow; three out of fifty colonoscopies revealed invasive colorectal carcinomas in threse patients. The remaining 47 colonoscopies for 47 patients revealed benign polyps. The sizes of these polyps were as follows; (6 polyps were ˃1 cm in diameter), (17 polyps were 6-9 mm), and (24 polyps were ≤5 mm). CT pneumocolon detected all 3 malignant masses seen and biopsied by colonoscopy, but only (28 single polyps) which according to their size (4 polyps were ≥ 1cm), (11 polyps were 6-9 mm) and (13 polyps ≤5 mm), this gives CT pneumocolon a sensitivity of (63%), specificity of (70%) and accuracy (63%). Conclusion: CT pneumocolon has high sensitivity and specificity for a detection of large-sized masses, but not for small ones. CT pneumocolon may be suitable for investigating patients with symptomatic colorectal masses noninvasively. Keywords: Pneumocolon, colonoscopy, polyp, colonic carcinoma

HISTOPATOLOGIA DA POLIPOSE ADENOMATOSA FAMILIAR E SUA ASSOCIAÇÃO COM O ADENOCARCINOMA COLORRETAL

Introdução: Adenomas são lesões precursoras com potencial evolutivo para malignidade entre 5 e 15 anos. Doenças como a polipose adenomatosa familiar (PAF) aumentam o risco de desenvolvimento do câncer colorretal. Objetivos: Descrever a histologia colorretal, correlacionando à PAF e sua evolução para adenocarcinoma colorretal. Material e métodos: Pesquisa bibliográfica nas bases Pubmed e Scielo, com os descritores: “familial adenomatous polyposis” e “colorectal neoplasms”. Foram utilizados: Robbins Patologia Básica 9ª Ed.; Junqueira e Carneiro Histologia Básica 13ª Ed. Resultados: O intestino grosso possui mucosa de tecido epitelial simples cilíndrico com células caliciformes e criptas de Lieberküng, lâmina própria de tecido conjuntivo frouxo e muscular da mucosa. A submucosa contém tecido conjuntivo denso e plexo de Meissner. A muscular própria possui duas subcamadas musculares lisas: circular interna, longitudinal externa, e plexo de Auerbach. Por fim, a serosa/adventícia possui tecido conjuntivo frouxo e adiposo. A PAF é uma doença autossômica dominante caracterizada pelo desenvolvimento de adenomas entéricos. Ela resulta da mutação no supressor tumoral adenomatous polyposis coli, responsável pela estabilidade genômica e apoptose. Se não tratados precocemente, 100% dos pacientes acometidos desenvolverá câncer colorretal. Na forma clássica, apresenta inúmeros adenomas, que evoluem para câncer rapidamente. Na atenuada, há menos adenomas, menor agressividade e progressão lenta. Estruturalmente, os adenomas são tubulares, vilosos ou túbulo-vilosos, classificação essencial para conhecimento do potencial maligno. A displasia epitelial de baixo grau nos adenomas possui núcleos alongados e pseudoestratificados, com pequenos nucléolos, enquanto a de alto grau apresenta núcleos redondos, estratificação e nucléolo proeminente. No cólon proximal, os adenocarcinomas são polipóides e exofíticos, raramente causando obstrução. Já no distal, são lesões anulares com estreitamento luminal e oclusão. Clinicamente, no cólon direito ocorre anemia ferropriva e no esquerdo sangramento oculto, alterações intestinais e cólicas. Microscopicamente, os adenocarcinomas bem diferenciados possuem células colunares altas, semelhantes aos adenomas, com componente invasivo causador de resposta desmoplásica, ocasionando consistência firme. Os pouco diferenciados formam glândulas e produzem mucina. Ainda, estas neoplasias podem apresentar diferenciação neuroendócrina. Conclusão: As características da PAF explicam sua correlação com o desenvolvimento de carcinomas colorretais. Assim, destaca-se a importância do estudo histopatológico, facilitando a compreensão evolutiva adenomas-câncer neste grupo populacional.

Gut microbiota imbalance in colorectal cancer patients, the risk factor of COVID-19 mortality

Background COVID-19 pandemic is sweeping across the world. Previous studies have shown that gut microbiota is associated with COVID-19, and operational taxonomic unit (OTU) composed of Blautia genus, Lactobacillus genus, and Ruminococcus genus of Firmicutes is correlated with the severity of COVID-19. Gut microbiota imbalance in colorectal cancer patients may lead to the variation of OTU. Results Based on the GMrepo database, the gut microbiota of 1374 patients with colorectal neoplasms and 27,329 healthy people was analyzed to investigate the differences in the abundance of microbes between colorectal neoplasms patients and healthy people. Furthermore, We collected feces samples from 12 patients with colorectal cancer and 8 healthy people in Xiangya hospital for metabolomic analysis to investigate the potential mechanisms. Our study showed that the abundance of Blautia and Ruminococcus was significantly increased in colorectal neoplasms, which may increase the severity of COVID-19. The gender and age of patients may affect the severity of COVID-19 by shaping the gut microbiota, but the BMI of patients does not. Conclusions Our work draws an initial point that gut microbiota imbalance is a risk factor of COVID-19 mortality and gut microbiota may provide a new therapeutic avenue for colorectal cancer patients.

Effectiveness of Inner Traction Facilitated Endoscopic Submucosal Dissection using Rubber Band and Clips for Colorectal Neoplasms: A Propensity Score-matched Study

Background Colorectal endoscopic submucosal dissection (ESD) is a technically demanding but effective treatment for superficial neoplasms. We conducted a study to compare the effectiveness and safety of inner traction facilitated ESD using rubber band and clip (RAC-ESD) with conventional ESD.Methods We retrospectively evaluated 622 consecutive patients underwent colorectal ESD between January 2016 and December 2019. To overcome selection bias, we used propensity score matching (1:4) between RAC-ESD and conventional ESD. The frequency of en bloc resections, R0 resections, curative resections, procedure speed and complications were evaluated.Results After propensity score matching, 35 patients were included in RAC-ESD group and 140 were included in conventional ESD group. RAC-ESD resulted in a significant increase in resection speed (0.14 vs. 0.09 cm2/min; P=0.003). There were no significant differences in en bloc, R0 and curative resection rates between two groups. In subgroup analysis, the resection speed of RAC-ESD was significantly higher than conventional ESD when the lesions were equal to or larger than 2cm, macroscopically presenting as lateral spreading tumor, and located in transverse colon to ascending colon.Conclusions RAC-ESD is safe and effective in treating colorectal neoplasms, especially in lesions presenting particular difficulty.