Infliximab in inflammatory bowel disease. Is premedication necessary? / Infliximab en enfermedad inflamatoria intestinal. ¿Es necesario premedicar?

BACKGROUND: The use of infliximab (IFX) in inflammatory bowel disease (IBD) has been associated with a 1-6% risk of infusion reactions. The usefulness of premedication with corticosteroids, paracetamol and /or antihistamines is controversial. AIM: The aim of this study is to assess, in IBD patients on IFX, whether there are differences in secondary reactions to the infusion between those who use premedication or not. METHODS: A retrospective cohort study was performed identifying patients with a diagnosis of IBD who received IFX at our institution between January 2009 and July 2019. Acute reactions were defined as those that occurred in the first 24 hours postinfusion and late reactions for more than 24 hours. Infusion reactions were classified as mild, moderate and severe. Descriptive and association statistics were used (χ2; p < 0.05). RESULTS: Sixty-four patients were included with 1,263 infusions in total, 52% men. Median infusions per patient was 22 (2-66). All induction infusions were administered with premedication, and in maintenance in 57% of them. Premedication was given with hydrocortisone, chlorphenamine and paracetamol. Most of reactions were acute, mild or moderate in severity and no patient needed to discontinue IFX. In the maintenance group, there were 9/718 (1.2%) infusion reactions with premedication and 4/358 (1.1%) without it (p = 0.606). In the induction group, there were 8/187 (4.3%) infusion reactions, significantly higher when compared with both maintenance groups. CONCLUSIONS: In this group, premedication use during maintenance was not effective at reducing the rate of infusion reactions. These results suggest that premedication would not be necessary.

Pregnancy in Inflammatory Bowel Disease: Experience of a Chilean cohort. / Embarazo en enfermedad inflamatoria intestinal: experiencia en una cohorte chilena.

BACKGROUND: In inflammatory bowel disease (IBD) a high percentage of women are diagnosed during their reproductive age. IBD in remission is the ideal scenario when planning a pregnancy. AIMS: To describe the clinical characteristics of pregnancy/newborn and assess disease activity at the time of conception and throughout the pregnancy in patients with IBD treated at a tertiary centre in Chile. METHODS: We retrospectively reviewed women diagnosed with IBD who were pregnant or delivered between 2017 and 2020. Demographic, clinical, obstetric and delivery data were obtained from the IBD registry, approved by the local IRB. Descriptive statistics and association tests were performed (χ2, p ≤ 0.05). RESULTS: Sixty women with IBD were included. At the beginning of pregnancy, 21 (35%) had active disease and 39 (65%) were in remission. Of those with active disease, 16 (66%) remained active and 6 had spontaneous abortions. In those who were in remission, 26 (69%) remained in this condition. Nine patients (15%) discontinued treatment, and 6 of these had inflammatory activity during pregnancy. Preconception counselling was performed in 23 of the 60 patients, being higher in the group that remained in remission during pregnancy (65% vs. 35%, p = 0.02). Patients who had a flare during pregnancy had more probability of preterm birth (<37 weeks) and newborn with lower weight compared with the group that always remained in remission (89% vs. 74%, p = 0.161) and (2.885 vs 3.370 g; p = 0.0014). CONCLUSION: Remission presents better outcomes in pregnancy and preconception counselling would allow a better IBD control during pregnancy.

Are patients with inflammatory bowel disease receiving adequate immunisation? / ¿Están recibiendo los pacientes con enfermedad inflamatoria intestinal una adecuada inmunización?

INTRODUCTION: Inflammatory Bowel Disease (IBD) treatment may increase the risk of infections. Vaccines are part of the comprehensive IBD patient care. The aim of this study was to describe indications and adherence of immunizations in IBD and identify possible associated factors. METHODS: A cross-sectional, analytic study was conducted in patients from an IBD Program of a tertiary center in Chile, between April - June 2019. Patients were asked to answer a vaccine survey and information also was obtained from the National Immunization Registry. Descriptive and association statistic were used (χ2; p<0.05). RESULTS: A total of 243 patients were included (148 ulcerative colitis (UC), 86 Crohn's disease (CD) and 9 non-classifiable IBD). Only six patients (2%) of IBD patients received a complete immunization schedule. The highest vaccine rates were against influenza (67%), hepatitis B virus (40%), 13-valent pneumococcal (34%) and 23-polysaccharide pneumococcal (16%). The influenza vaccine rate has significantly increased, reaching 67% in 2019. The survey showed that 23% of patients have not been immunized with any vaccine, mainly due to lack of time, lack of medical prescription and high cost. CONCLUSIONS: In this cohort, although vaccination rates are higher than previously reported, adherence to IBD immunization program would be improved, being considered since diagnosis by the multidisciplinary team.

Characterization of Chilean patients with sporadic colorectal cancer according to the three main carcinogenic pathways: Microsatellite instability, CpG island methylator phenotype and Chromosomal instability.

Molecular classification of colorectal cancer is difficult to implement in clinical settings where hundreds of genes are involved, and resources are limited. This study aims to characterize the molecular subtypes of patients with sporadic colorectal cancer based on the three main carcinogenic pathways microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and chromosomal instability (CIN) in a Chilean population. Although several reports have characterized colorectal cancer, most do not represent Latin-American populations. Our study includes 103 colorectal cancer patients who underwent surgery, without neoadjuvant treatment, in a private hospital between 2008 and 2017. MSI, CIN, and CIMP status were assessed. Frequent mutations in KRAS, BRAF, and PIK3CA genes were analyzed by Sanger sequencing, and statistical analysis was performed by Fisher's exact and/or chi-square test. Survival curves were estimated with Kaplan-Meier and log-rank test. Based on our observations, we can classify the tumors in four subgroups, Group 1: MSI-high tumors (15%) are located in the right colon, occur at older age, and 60% show a BRAF mutation; Group 2: CIN-high tumors (38%) are in the left colon, and 26% have KRAS mutations. Group 3: [MSI/CIN/CIMP]-low/negative tumors (30%) are left-sided, and 39% have KRAS mutations; Group 4: CIMP-high tumors (15%) were more frequent in men and left side colon, with 27% KRAS and 7% presented BRAF mutations. Three percent of patients could not be classified. We found that CIMP-high was associated with a worse prognosis, both in MSI-high and MSI stable patients (p = 0.0452). Group 3 (Low/negative tumors) tend to have better overall survival compared with MSI-high, CIMP-high, and CIN-high tumors. This study contributes to understanding the heterogeneity of tumors in the Chilean population being one of the few characterizations performed in Latin-America. Given the limited resources of these countries, these results allow to improve molecular characterization in Latin-American colorectal cancer populations and confirm the possibility of using the three main carcinogenic pathways to define therapeutic strategies.

The Role of an Inflammatory Bowel Disease Nurse in the Follow-Up of Patients From a Latin American Inflammatory Bowel Disease Program.

Inflammatory bowel disease requires long-term treatment to maintain disease control. Favorable follow-up of patients indicates attention from a multidisciplinary team, in which the nurse's responsibilities have great importance. The aim of this observational, descriptive study was to describe the role of an inflammatory bowel disease nurse in the management of patients in a tertiary center in Chile, including all patients in follow-up between January 2016 and April 2017. Inflammatory bowel disease nurse contacts were recorded and classified. Demographic data, clinical variables, and patient satisfaction were also analyzed. A total of 597 patients (51%) were in follow-up over the 16-month period; 63% had ulcerative colitis, with a median age of 35 years. The inflammatory bowel disease nurse performed 760 contacts in 253 patients (42% of the follow-up patients). The most frequent nurse interventions were reinforcement of medical indications (42%), assessment of laboratory results (17%), and disease follow-up (12%); 49% related to education. Nurse interventions were focused in more severely ill patients; flares during the follow-up, biological therapy, immunomodulators, and steroids were all statistically significant. Of a sample of 107 patients surveyed, 96% perceived the inflammatory bowel disease program as excellent/good. The inflammatory bowel disease nurse plays an important role in the follow-up and management, specifically in education, of more severely ill patients.

[Environmental risk factors in the development and evolution of inflammatory bowel disease]. / Factores ambientales en el desarrollo y evolución de la enfermedad inflamatoria intestinal.

Environmental factors may influence the development of Inflammatory Bowel Disease and modify its natural history. The objective of this review is to evaluate current evidence about environmental factors associated with the disease. A better knowledge about the pathogenesis of the disease can lead to better treatment strategies and suggestions to prevent the disease.

The relationship between chemokines CCL2, CCL3, and CCL4 with the tumor microenvironment and tumor-associated macrophage markers in colorectal cancer.

A complex network of chemokines can influence cancer progression with the recruitment and activation of hematopoietic cells, including macrophages to the supporting tumor stroma promoting carcinogenesis and metastasis. The aim of this study was to investigate the relation between tissue and plasma chemokine levels involved in macrophage recruitment with tumor-associated macrophage profile markers and clinicopathological features such as tumor-node-metastases stage, desmoplasia, tumor necrosis factor-α, and vascular endothelial growth factor plasma content. Plasma and tumor/healthy mucosa were obtained from Chilean patients undergoing colon cancer surgery. Chemokines were evaluated from tissue lysates (CCL2, CCL3, CCL4, CCL5, and CX3CL1) by Luminex. Statistical analysis was performed using Wilcoxon match-paired test ( p < 0.05). Macrophage markers (CD68, CD163, and iNOS) were evaluated by immunohistochemistry samples derived from colorectal cancer patients. Correlation analysis between chemokines and macrophage markers and clinicopathological features were performed using Spearman's test. Plasmatic levels of chemokines and inflammatory mediators' vascular endothelial growth factor and tumor necrosis factor-α were evaluated by Luminex. Tumor levels of CCL2 (mean ± standard deviation = 530.1 ± 613.9 pg/mg), CCL3 (102.7 ± 106.0 pg/mg), and CCL4 (64.98 ± 48.09 pg/mg) were higher than those found in healthy tissue (182.1 ± 116.5, 26.79 ± 22.40, and 27.06 ± 23.69 pg/mg, respectively p < 0.05). The tumor characterization allowed us to identify a positive correlation between CCL4 and the pro-tumor macrophages marker CD163 ( p = 0.0443), and a negative correlation of iNOS with desmoplastic reaction ( p = 0.0467). Moreover, we identified that tumors with immature desmoplasia have a higher CD163 density compared to those with a mature/intermediated stromal tissue ( p = 0.0288). Plasmatic CCL4 has shown a positive correlation with inflammatory mediators (tumor necrosis factor-α and vascular endothelial growth factor) that have previously been associated with poor prognosis in patients. In conclusion High expression of CCL4 in colon cancer could induce the infiltration of tumor-associated macrophages and specifically a pro-tumor macrophage profile (CD163+ cells). Moreover, plasmatic chemokines could be considered inflammatory mediators associated to CRC progression as well as tumor necrosis factor-α and vascular endothelial growth factor. These data reinforce the idea of chemokines as potential therapeutic targets or biomarker in CRC.

Stem Cell Therapy in Refractory Perineal Crohn's Disease: Long-term Follow-up.

AIM: To describe the long-term outcomes of adipose-mesenchymal stem cells, platelet-rich plasma, and endorectal advancement flaps in patients with Perineal Crohn's Disease. METHOD: This was a single-center, prospective, observational pilot study performed between March 2013 and December 2016. The study included adult patients diagnosed with Perianal Crohn's Disease (with complex perianal fistulas) refractory to previous surgical and/or biological treatment. Patients underwent surgical treatment in two stages. Stage 1: Fistula mapping, drainage, seton placement and lipoaspiration to obtain adipose-mesenchymal stem cells were performed. Stage 2: The setons were removed, and the fistula tract was debrided. A small endorectal advancement flap was created, with closure of the previous internal fistula opening. Then, 100-120 million adipose-mesenchymal stem cells mixed with platelet-rich plasma were injected into the internal fistula opening and fistula tract. RESULTS: The study included nine patients (seven females), with a median age of 36 years (r = 23-57). Eleven fistula tracks were treated, of which, two were pouch-vaginal fistulas. The median follow-up period was 31 months (r=21-37). At the end of the follow-up period, 10/11 (91%) fistulas were completely healed and 1/11 (9%) was partially healed. At the end of this period, there was no evidence of fistula relapse or adverse reactions in any patients. The Perianal Disease Activity Index and Inflammatory Bowel Disease Questionnaire scores significantly improved after the procedure. CONCLUSION: Combined therapy with adipose-mesenchymal stem cells, platelet-rich plasma and endorectal advancement flaps yielded good results in patients with refractory Perineal Crohn's Disease. This article is protected by copyright. All rights reserved.

A Pilot Trial to Quantify Plasma Exosomes in Colorectal Cancer Screening from the International Collaborative Study between Chile and Japan.

BACKGROUND: In Chile, a national colorectal cancer (CRC) screening program using immunochemical fecal occult blood tests and colonoscopy was started in 2012 as an international collaboration between Chile and Japan. In the present study, we quantified exosomes in the peripheral blood and evaluated the implication of the results for CRC screening. METHODS: A total of 25 peripheral plasma samples from the participants of CRC screening in Punta Arenas, Chile, were analyzed for exosomes. RESULTS: Plasma exosomes were obtained from 5 participants with adenocarcinoma (4 pTis and 1 pT1), 8 with high-grade adenoma, 4 with low-grade adenoma, 4 with hyperplastic polyps, and 4 with normal findings. Participants with adenocarcinoma had significantly higher amounts of plasma exosomes (2.1-3.2 fold) than participants with normal findings, hyperplastic polyps, or low-grade adenoma (p = 0.016, p = 0.0034, and p = 0.0042 respectively; Tukey's multiple comparisons test). The size of the representative lesion, the number of lesions, and the sum of those 2 factors in each participant correlated significantly with the exosome amounts (r = 0.56, r = 0.58, and r = 0.72, respectively; p < 0.01; Spearman's correlation coefficient test). CONCLUSIONS: This pilot study demonstrated that quantification of plasma exosomes is a potential alternative screening method for detecting individuals with a high risk of colorectal malignancy.

[Results of a multicentric colorectal cancer screening program in Chile]. / Programa multicéntrico de cribado de cáncer colorrectal en Chile.

BACKGROUND: Colorectal Cancer Screening Programs (CRCSP) are widely accepted in developed countries. Unfortunately, financial restrictions, low adherence rate and variability on colonoscopy standardization hamper the implementation of CRCSP in developing countries. AIM: To analyze a multicentric pilot model of CRCSP in Chile. MATERIAL AND METHODS: A prospective model of CRCSP was carried out in three cities, from 2012 to 2015. The model was based on CRC risk assessment and patient education. Health care personnel were trained about logistics and protocols. The endoscopy team was trained about colonoscopy standards. A registered nurse was the coordinator in each center. We screened asymptomatic population aged between 50 and 75 years. Immunological fecal occult blood test (FIT) was offered to all participants. Subjects with positive FIT underwent colonoscopy. RESULTS: A total of 12,668 individuals were enrolled, with a FIT compliance rate of 93.9% and 2,358 colonoscopies were performed. Two hundred and fifty high-risk adenomas and 110 cancer cases were diagnosed. One patient died before treatment due to cardiovascular disease, 74 patients (67%) underwent endoscopic resection and 35 had surgical treatment. Ninety one percent of patients had an early stage CRC (0-I-II). Among colonoscopy indicators, 80% of cases had an adequate bowel preparation (Boston > 6), cecal intubation rate was 97.7%, adenoma detection rate was 36.5%, and in 94.5% of colonoscopies, withdrawal time was adequate (> 8 min). CONCLUSIONS: This CRCS pilot model was associated to a high rate of FIT return and colonoscopy quality standards. Most CRCs detected with the program were treated by endoscopic resection.

EGFR pathway subgroups in Chilean colorectal cancer patients, detected by mutational and expression profiles, associated to different clinicopathological features.

Colorectal cancer is a multistep process affecting several signaling pathways including EGFR (epidermal growth factor receptor), a therapeutic target for metastatic disease. Our aim was to characterize the mutational and expression profiles of the EGFR pathway in colorectal tumors and to integrate these results according to five previously defined groups. We screened seven genes for mutations ( KRAS-BRAF-PIK3CA-PIK3R1-AKT1-MAP2K1-PTEN) and six proteins (EGFR-p110α-p85α-PTEN-phosphoAKT-phosphoMEK1) by immunohistochemistry, PTEN deletion, and MSI. At least one mutated gene was observed in 68% of tumors ( KRAS 45%, PIK3CA 21%, BRAF 14%, and PTEN 7%). PTEN deletion was observed in 10.7% of tumors and 19.6% were MSI-High. In all, 54% of tumors showed a high EGFR expression, 48% p110α, 4.4% phosphoAKT, and 22% phosphoMEK1; and 43% showed low PTEN expression and 22% p85α. In total, five groups of tumors were defined based on MSI, BRAF, and KRAS mutations. Three groups gather mainly early-stage tumors, whereas a fourth group is mostly conformed by advanced tumors. We described here that 71.4% of tumors from one group have a mutated PI3K/PTEN pathway, in comparison to other groups having 32%, 27%, and 25%. In addition, the five groups are differentiated by molecular features such as EGFR, p85α, p110α, and PTEN, showing variable expression among tumor groups. In conclusion, alterations on the EGFR pathway were found in a high percentage of colorectal cancer patients. Using the integration of diverse molecular markers, we ratified previous classification in an ethnic group having relevant genetic differences and living in a different environmental background, adding complementary molecular targets related to therapy.

Assessment of disease-related knowledge and possible factors associated with the knowledge level among Chilean patients with inflammatory bowel disease.

AIMS AND OBJECTIVES: To assess disease-related knowledge among patients with inflammatory bowel disease and to identify the factors that are possibly associated with the knowledge level. BACKGROUND: Disease-related knowledge can positively influence the acceptance of the disease, increase treatment compliance and improve the quality of life in patients with inflammatory bowel disease. DESIGN: An observational, cross-sectional study was conducted and prospectively included patients from the inflammatory bowel disease programme between October 2014-July 2015. METHODS: A Spanish-translated version of the 24-item Crohn's and Colitis Knowledge score was used to assess disease-related knowledge. Patients also completed a demographic and clinical questionnaire. RESULTS: A total of 203 patients were included, 62% were female, and 66% were diagnosed with ulcerative colitis; the median age was 34 years (range 18-79), and the median disease duration was four years. The median disease-related knowledge score was 9 (range 1-20). Only 29% of the patients answered more than 50% of the questions correctly. Lower disease-related knowledge was observed in questions related to pregnancy/fertility and surgery/complications. Patients older than 50 years, with ulcerative colitis, with disease durations less than five years and patients without histories of surgery exhibited lower disease-related knowledge. There was no association between the knowledge scores and the educational levels. CONCLUSIONS: The patients who attended our inflammatory bowel disease programme exhibited poor disease-related knowledge that was similar to the knowledge levels that have been observed in developed countries. It is necessary to assess patient knowledge to develop educational strategies and evaluate the influences of these strategies on patient compliance and quality of life. RELEVANCE TO CLINICAL PRACTICE: These results will allow the inflammatory bowel disease team to develop educational programmes that account for the disease-related knowledge of each patient. Inflammatory bowel disease nurses should evaluate their interventions to provide evidence that educating our patients contributes to improving their treatment outcomes and overall health statuses.

[Acute severe ulcerative colitis treated with accelerated infliximab induction. Case report]. / Terapia de inducción acelerada con infliximab en paciente con colitis ulcerosa grave refractaria a corticoides. Caso clínico.

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening condition that requires early recognition, hospitalization and adequate treatment. Currently, the use of infliximab in ulcerative colitis (UC) is recommended in the case of severe disease refractory to corticosteroids, once that superimposed bacterial or viral infections (such as cytomegalovirus or Clostridium difficile) have been excluded. However, conventional weight-based regimens of infliximab might be insufficient for patients with ASUC. Accelerated infliximab induction regimen may increase its serum concentration levels and efficacy by reducing early colectomy rates in these patients. We report a 34 year old female presenting with an ASUC. She was initially treated with hydrocortisone 300 mg/day and mesalazine enemas 4 g/day with an unfavorable clinical response. At the fifth day of therapy, an accelerated induction therapy with infliximab was started in doses of 10 mg/kg at weeks 0, 1 and 4. After the second dose, there was a favorable response with reduction of abdominal pain, stool frequency and hematochezia. She was discharged with prednisone and azathioprine. After a year of starting infliximab, the patient remains in clinical remission.

[Acute small bowel diverticulitis in a patient with crohn’s disease]. / Diverticulitis aguda de intestino delgado en un paciente con enfermedad de Crohn: Report of one case.

Diverticular disease of the small intestine is rare, especially when it is located in the jejunum. It is generally asymptomatic, but in some patients it may have complications such as acute diverticulitis with peritonitis, gastrointestinal bleeding or obstruction. In such cases, the recommended treatment is surgery. We report a 77-year-old patient with ileal Crohn’s disease with a long-standing inflammatory phenotype, who developed acute diverticulitis of the jejunum presenting a severe septic shock and secondary multiple-organ failure. It resolved with medical treatment and prolonged antibiotic therapy.

[Rectal diffuse large B cell lymphoma appearing after immunosuppression for ulcerative colitis. Report of one case]. / Linfoma difuso de células grandes B rectal en un paciente con colitis ulcerosa.

Primary colorectal lymphoma is a rare form of presentation of gastrointestinal tract lymphomas. Inflammatory bowel disease and its treatment are risk factors for its development. We report a 47-year-old male patient with Ulcerative Colitis of two years of evolution, treated initially with azathioprine and later on with infliximab. Due to a relapse in symptoms after the second dose of infliximab, a new coloncoscopy was performed showing a rectal ulcerative lesion, corresponding to a large cell Non-Hodgkin's Lymphoma. The patient was successfully treated with RCHOP chemotherapy (Rituximab cyclophosphamide doxorubicin vincristine prednisone). He is currently in disease remission.

[Characterization of patients with sporadic colorectal cancer following the new Consensus Molecular Subtypes (CMS)]. / Caracterización de pacientes con cáncer colorrectal esporádico basado en la nueva subclasificación molecular de consenso.

BACKGROUND: Colorectal cancer (CRC) is an heterogeneous disease. Three carcinogenic pathways determine its molecular profile: microsatellite instability (MSI), chromosomal instability (CIN) and CpG island methylator phenotype (CIMP). Based on the new molecular classification, four consensus CRC molecular subtypes (CMS) are established, which are related to clinical, pathological and biological characteristics of the tumor. AIM: To classify Chilean patients with sporadic CRC according to the new consensus molecular subtypes of carcinogenic pathways. MATERIAL AND METHODS: Prospective analytical study of 53 patients with a mean age of 70 years (55% males) with CRC, operated at a private clinic, without neoadjuvant treatment. From normal and tumor tissue DNA of each patient, CIN, MSI and CIMP were analyzed. Combining these variables, tumors were classified as CMS1/MSI-immune, CMS2/canonical, CMS3/metabolic and CMS4/mesenchymal. RESULTS: CMS1 tumors (19%) were located in the right colon, were in early stages, had MMR complex deficiencies and 67% had an activating mutation of the BRAF oncogene. CMS2 tumors (31%) were located in the left colon, had moderate differentiation, absence of vascular invasion, lymphatic and mucin. CMS3 tumors (29%) were also left-sided, with absence of vascular and lymphatic invasion, and 29% had an activating mutation of the KRAS oncogene. CMS4 tumors (21%) showed advanced stages and presence of metastases. CONCLUSIONS: This new molecular classification contributes to understanding the heterogeneity of tumors. It is possible to differentiate molecular subgroups of a single pathological diagnosis of adenocarcinoma, opening the door to personalized medicine.

[Natalizumab for the treatment of Crohn’s disease: Report of three cases]. / Experiencia local con natalizumab en pacientes con enfermedad de Crohn refractaria a anti-TNF: Casos clínicos.

Anti-tumor necrosis factor-α (TNF) agents have dramatically changed the management of Crohn’s Disease (CD). However, a significant number of these patients do not respond at all or cease to respond to antibodies against TNF. In this clinical situation, the options include intensification of anti-TNF therapy by either increasing the dose or by shortening the administration interval, the use of a second anti-TNF or medications with a different mechanism of action. Among the later, Natalizumab, a humanized IgG4 monoclonal antibody against α4ß1 and α4ß7 integrins, is safe and effective in inducing and maintaining remission in active CD patient’s refractory to anti-TNF. In spite of this, Natalizumab use has been limited because of an increased risk of progressive multifocal leukoencephalophaty which results from reactivation of the John Cunningham (JC) virus. However, the presence of antibodies against JC virus in serum can be used to reduce the risk for this complication. We report three patients with Crohn’s disease refractory to treatment with infliximab, who responded successfully to the use of Natalizumab.

International collaboration between Japan and Chile to improve detection rates in colorectal cancer screening.

BACKGROUND: In Chile, mortality from colorectal cancer (CRC) has increased rapidly. To help address this issue, the Prevention Project for Neoplasia of the Colon and Rectum (PRENEC) program was initiated in 2012 with intensive support from Tokyo Medical and Dental University (TMDU) in Tokyo, Japan, as part of an international collaboration. METHODS: From June 2012 to July 2014, a total of 10,575 asymptomatic participants were enrolled in PRENEC. Participants with positive immunochemical fecal occult blood test (iFOBT) results or a family history of CRC underwent colonoscopy. The colonoscopy results from a similar, previous project in Chile (PREVICOLON) were compared with those from PRENEC. Furthermore, the initial colonoscopies of 1562 participants in PRENEC were analyzed according to whether the colonoscopists were from TMDU or Chile. RESULTS: The complete colonoscopy, adenoma detection, and cancer detection rates were 88.0%, 26.7%, and 1.1%, respectively, in PREVICOLON, while the corresponding values were 94.4%, 41.8%, and 6.0%, respectively, in PRENEC. In PRENEC, 107 cases of CRC were detected, amounting for 1.0% of all participants. Considering initial colonoscopies in PRENEC, the complete colonoscopy, adenoma detection, and cancer detection rates were 97.4%, 45.3%, and 9.3%, respectively, for physicians at TMDU and 93.3%, 41.5%, and 5.1%, respectively for Chilean physicians. The detection rates of intramucosal cancer were 7.3% and 3.7%, respectively, for TMDU and Chilean physicians. CONCLUSIONS: Quality indicators of colonoscopy substantially improved from PREVICOLON to PRENEC. The assessments made by Chilean physicians alone were improved in PRENEC, but remained better in the TMDU group. Moreover, physicians from TMDU detected more CRCs than Chilean physicians, especially at earlier stages.