Where does capsule endoscopy fit in the diagnostic algorithm of small bowel intussusception?

INTRODUCTION: The investigation of small bowel (SB) intussusception is variable, reflecting the lack of existing standards. The aim of this study was to understand the role of small bowel capsule endoscopy (SBCE) to investigate this pathology. METHODOLOGY: This was a retrospective multi-centre study. Patients with intussusception on SBCE and those where SBCE was carried out due to findings of intussusception on radiological investigations were included. Relevant information was collected. RESULTS: Ninety-five patients (median age 39+/-SD19.1 years, IQR 30) were included. Radiological investigations were carried out in 71 patients (74.7%) prior to SBCE with intussusception being present in 60 patients on radiological investigations (84.5%). Thirty patients (42.2%) had intussusception on radiological investigations followed by a normal SBCE. Ten patients (14.1%) had findings of intussusception on radiological investigations, a normal SBCE and repeat radiological investigations that were also normal. Abnormal findings were noted on SBCE that could explain intussusception on imaging in (16 patients) 22.5% of patients. Five patients (5.3%) underwent radiological investigations and SBCE to investigate coeliac disease and intussusception. None had associated malignancy. Four patients (4.2%) underwent SBCE to investigate familial polyposis syndromes and went on to SB enteroscopy and surgery accordingly. Most patients (n = 14; 14.8%) with intussusception on initial SBCE (without prior radiological imaging) had suspected SB bleeding (n = 10, 10.5%). Four patients (4.2%) had additional findings of a mass on CT scan and went on to have surgery. CONCLUSION: SBCE should be used to complement radiology when investigating intussusception. It is a safe non-invasive test that will minimise unnecessary surgery. Additional radiological investigations following a negative SBCE in cases of intussusception noted on initial radiological investigations are unlikely to yield positive findings. Radiological investigations following intussusception noted on SBCE in case of patients presenting with obscure gastrointestinal bleeding, may yield additional findings.

Oral ingestion versus endoscopic delivery of endoscopic capsule in patients with previous gastrointestinal surgery (ORENCES study): A Spanish multicentre observational study / Ingesta oral versus colocación endoscópica de la cápsula endoscópica en pacientes con cirugía gastrointestinal previa (estudio ORENCES): un estudio observacional multicéntrico español

Background: Small Bowel Capsule Endoscopy is the first-choice technique for investigating the majority of small bowel diseases. Its most common complications are related to incomplete examinations and capsule retention. There is no consensus on how patients with previous gastrointestinal surgery should receive the capsule. Objective: The primary endpoint was to compare the rate of complete small-bowel examinations (completion rate) between oral ingestion and endoscopic delivery of the capsule. The secondary endpoint was to compare diagnostic yield and adverse events in the two groups. Methods: A retrospective observational study was conducted in nine hospitals in Spain. Demographic data, previous surgery, indication for capsule endoscopy, intestinal transit time, diagnosis, completion rate (percentage of capsules reaching the caecum), diagnostic yield (percentage of results compatible with indication for the exam) and adverse events were collected. Results: From January 2009 to May 2019 fifty-seven patients were included (39 male, mean age 66±15 years). The most common indications for the exam were “overt” (50.9%) and “occult” (35.1%) small bowel bleeding. Previous Billroth II gastrectomy and Roux-en-Y gastric bypass were present in 52.6% and 17.5% of patients respectively. The capsule was swallowed in 34 patients and placed endoscopically in 23 patients. No significant differences were observed between the oral ingestion and endoscopic delivery groups in terms of completion rate (82.4% vs. 78.3%; p=0.742), diagnostic yield (41.2% vs. 52.2%; p=0.432) or small bowel transit time (301 vs. 377min, p=0.118). No capsule retention occurred. Only one severe adverse event (anastomotic perforation) was observed in the endoscopic delivery group. Conclusions: In our case series, there were no significant differences between oral ingestion and endoscopic delivery in terms of completion rate, diagnostic yield or safety.(AU)

Antecedentes: La cápsula endoscópica representa la técnica de primera elección para investigar la mayoría de las enfermedades del intestino delgado. Sus complicaciones más comunes frecuentes son las exploraciones incompletas y la retención a nivel de intestino delgado. Hasta el momento no hay acuerdo sobre cómo administrar la cápsula a los pacientes que han sido sometidos a una cirugía gastrointestinal previa. Objetivo: El objetivo principal fue comparar la tasa de estudios completos entre la ingestión oral y la administración endoscópica de la cápsula. Los objetivos secundarios fueron comparar el rendimiento diagnóstico y los eventos adversos en ambos grupos. Métodos: Se realizó un estudio observacional retrospectivo en 9 hospitales de España. Se recogieron datos demográficos, cirugía previa, indicación de cápsula endoscópica, tiempo de tránsito intestinal, diagnóstico, tasa de estudios completos (porcentaje de cápsulas que llegan al ciego), rendimiento diagnóstico (porcentaje de resultados compatibles con la indicación del examen) y eventos adversos. Resultados: Desde enero de 2009 hasta mayo de 2019 se incluyeron 57 pacientes (39 hombres, edad media 66 ± 15 años). Las indicaciones más frecuentes para el examen fueron hemorragia de intestino delgado «manifiesta» (50,9%) y «oculta» (35,1%). El 52,6% de los pacientes presentaba gastrectomía Billroth II y el 17,5% bypass gástrico en Y de Roux. La cápsula fue ingerida en 34 pacientes y colocada endoscópicamente en 23 pacientes. No se observaron diferencias significativas entre los grupos de ingesta oral y de colocación endoscópica en cuanto a tasa de estudios completos (82,4% vs. 78,3%; p = 0,742), rendimiento diagnóstico (41,2% vs. 52,2%; p = 0,432) y tiempo de tránsito del intestino delgado (301 vs. 377 min, p = 0,118). No hubo casos de cápsulas retenidas. Solo se observó un evento adverso severo (perforación anastomótica) en el grupo de colocación endoscópica...(AU)

Oral ingestion versus endoscopic delivery of endoscopic capsule in patients with previous gastrointestinal surgery (ORENCES study): A Spanish multicentre observational study.

BACKGROUND: Small Bowel Capsule Endoscopy is the first-choice technique for investigating the majority of small bowel diseases. Its most common complications are related to incomplete examinations and capsule retention. There is no consensus on how patients with previous gastrointestinal surgery should receive the capsule. OBJECTIVE: The primary endpoint was to compare the rate of complete small-bowel examinations (completion rate) between oral ingestion and endoscopic delivery of the capsule. The secondary endpoint was to compare diagnostic yield and adverse events in the two groups. METHODS: A retrospective observational study was conducted in nine hospitals in Spain. Demographic data, previous surgery, indication for capsule endoscopy, intestinal transit time, diagnosis, completion rate (percentage of capsules reaching the caecum), diagnostic yield (percentage of results compatible with indication for the exam) and adverse events were collected. RESULTS: From January 2009 to May 2019 fifty-seven patients were included (39 male, mean age 66±15 years). The most common indications for the exam were "overt" (50.9%) and "occult" (35.1%) small bowel bleeding. Previous Billroth II gastrectomy and Roux-en-Y gastric bypass were present in 52.6% and 17.5% of patients respectively. The capsule was swallowed in 34 patients and placed endoscopically in 23 patients. No significant differences were observed between the oral ingestion and endoscopic delivery groups in terms of completion rate (82.4% vs. 78.3%; p=0.742), diagnostic yield (41.2% vs. 52.2%; p=0.432) or small bowel transit time (301 vs. 377min, p=0.118). No capsule retention occurred. Only one severe adverse event (anastomotic perforation) was observed in the endoscopic delivery group. CONCLUSIONS: In our case series, there were no significant differences between oral ingestion and endoscopic delivery in terms of completion rate, diagnostic yield or safety. Being less invasive, oral ingestion of the capsule should be the first-choice method in patients with previous gastrointestinal surgery.

Development and validation of a scoring index to predict the presence of lesions in capsule endoscopy in patients with suspected Crohn's disease of the small bowel: a Spanish multicenter study.

BACKGROUND: Capsule endoscopy (CE) is the first-line investigation in cases of suspected Crohn's disease (CD) of the small bowel, but the factors associated with a higher diagnostic yield remain unclear. OBJECTIVE: Our aim is to develop and validate a scoring index to assess the risk of the patients in this setting on the basis of biomarkers. PATIENTS AND METHODS: Data on fecal calprotectin, C-reactive protein, and other biomarkers from a population of 124 patients with suspected CD of the small bowel studied by CE and included in a PhD study were used to build a scoring index. This was first used on this population (internal validation process) and after that on a different set of patients from a multicenter study (external validation process). RESULTS: An index was designed in which every biomarker is assigned a score. Three risk groups have been established (low, intermediate, and high). In the internal validation analysis (124 individuals), patients had a 10, 46.5, and 81% probability of showing inflammatory lesions in CE in the low-risk, intermediate-risk, and high-risk groups, respectively. In the external validation analysis, including 410 patients from 12 Spanish hospitals, this probability was 15.8, 49.7, and 80.6% for the low-risk, intermediate-risk, and high-risk groups, respectively. CONCLUSION: Results from the internal validation process show that the scoring index is coherent, and results from the external validation process confirm its reliability. This index can be a useful tool for selecting patients before CE studies in cases of suspected CD of the small bowel.

Role of capsule endoscopy in alarm features and non-responsive celiac disease: A European multicenter study.

BACKGROUND AND AIM: The role of capsule endoscopy (CE) in established celiac disease (CD) remains unclear. Our objective was to analyze the usefulness of CE in the suspicion of complicated CD. METHODS: This was a retrospective multicenter study. One hundred and eighty-nine celiac patients (mean age: 46.6 ± 16.6, 30.2% males) who underwent CE for alarm symptoms (n = 86, 45.5%) or non-responsive CD (n = 103, 54.5%) were included. Diagnostic yield (DY), therapeutic impact and safety were analyzed. RESULTS: Capsule endoscopy was completed in 95.2% of patients (small bowel transit time: 270.5 ± 100.2 min). Global DY was 67.2%, detecting atrophic mucosa (n = 92, 48.7%), ulcerative jejunoileitis (n = 21, 11.1%), intestinal lymphoma (n = 7, 3.7%) and other enteropathies (n = 7, 3.7%, six Crohn's disease cases and one neuroendocrine tumor). The DY of CE was significantly higher in patients presenting with non-responsive disease compared to patients with alarm symptoms (73.8% vs 59.3%, P = 0.035). The new findings of the CE modified management in 59.3% of the cases. There were no major complications. CONCLUSION: Capsule endoscopy may be a moderately helpful and safe diagnostic tool in the suspicion of complicated CD, modifying the clinical course of these patients.

Role of capsule endoscopy in suspected celiac disease: A European multi-centre study.

AIM: To analyze the diagnostic yield (DY), therapeutic impact (TI) and safety of capsule endoscopy (CE). METHODS: This is a multi-centre, observational, analytical, retrospective study. A total of 163 patients with suspicion of celiac disease (CD) (mean age = 46.4 ± 17.3 years, 68.1% women) who underwent CE from 2003 to 2015 were included. Patients were divided into four groups: seronegative CD with atrophy (Group-I, n = 19), seropositive CD without atrophy (Group-II, n = 39), contraindication to gastroscopy (Group-III, n = 6), seronegative CD without atrophy, but with a compatible context (Group-IV, n = 99). DY, TI and the safety of CE were analysed. RESULTS: The overall DY was 54% and the final diagnosis was villous atrophy (n = 65, 39.9%), complicated CD (n = 12, 7.4%) and other enteropathies (n = 11, 6.8%; 8 Crohn's). DY for groups I to IV was 73.7%, 69.2%, 50% and 44.4%, respectively. Atrophy was located in duodenum in 24 cases (36.9%), diffuse in 19 (29.2%), jejunal in 11 (16.9%), and patchy in 10 cases (15.4%). Factors associated with a greater DY were positive serology (68.3% vs 49.2%, P = 0.034) and older age (P = 0.008). On the other hand, neither sex nor clinical presentation, family background, positive histology or HLA status were associated with DY. CE results changed the therapeutic approach in 71.8% of the cases. Atrophy was associated with a greater TI (92.3% vs 45.3%, P < 0.001) and 81.9% of the patients responded to diet. There was one case of capsule retention (0.6%). Agreement between CE findings and subsequent histology was 100% for diagnosing normal/other conditions, 70% for suspected CD and 50% for complicated CD. CONCLUSION: CE has a high DY in cases of suspicion of CD and it leads to changes in the clinical course of the disease. CE is safe procedure with a high degree of concordance with histology and it helps in the differential diagnosis of CD.

Pacientes con trastorno funcional intestinal: eficacia de una dieta baja en FODMAPS para el tratamiento de los síntomas digestivos / Patients with functional bowel disorder: effectiveness of a diet low in FODMAPS for the treatment of gastrointestinal symptoms

Introducción: Investigaciones recientes indican que los síntomas digestivos que presentan los pacientes con trastorno funcional intestinal mejoran con la restricción en la dieta de los hidratos de carbono de cadena corta (Fermentable Oligosaccharides, Disaccharides and Monosaccharides and Polyols: FODMAPs). Objetivos: 1. Valorar la eficacia de una dieta baja en FODMAPs en la mejoría de los síntomas digestivos en pacientes con trastorno funcional intestinal y en aquellos con enfermedades orgánicas del tubo digestivo. 2. Examinar qué alimentos dentro de cada grupo de hidratos de carbono (fructanos, galactanos, lactosa, exceso de fructosa y polioles) vuelven a tolerar los pacientes, después de realizar una dieta de reintroducción de alimentos con FODMAPs. Método: Investigación prospectiva que estudió de forma consecutiva 164 pacientes con trastorno funcional intestinal tratados en la consulta del Área de Nutrición de un hospital universitario de España. Los síntomas que presentaban eran dolor abdominal, distensión, gases, diarreas y/o estreñimiento. Durante 6-8 semanas siguieron dieta baja en FODMAPs, analizando en todos los casos la mejoría y la adherencia al tratamiento dietético. Posteriormente siguieron la dieta de reintroducción de alimentos con FODMAPs, evaluando la tolerancia a cada uno de los alimentos. Resultados: El ochenta y cuatro por ciento de los pacientes presentaron mejoría de los síntomas digestivos con una alta adherencia al tratamiento. Después de realizar la dieta de reintroducción, más del 80% de los pacientes volvieron a tolerar trigo, así como lácteos con lactosa y más del 70% legumbres y 2 raciones de frutas bajas en fructosa en la misma toma. Conclusiones: 1. La dieta baja en FODMAPs es eficaz para mejorar la sintomatología digestiva de los pacientes con trastorno funcional intestinal. 2. La mayor adherencia a la dieta se asocia con una mejoría total de los síntomas digestivos. 3. La mayoría de los pacientes, tras realizar la dieta de reintroducción, vuelve a tolerar trigo, leche, derivados lácteos con lactosa y legumbres, así como una variedad de frutas con alto contenido en FODMAPs (AU)

Introduction: Recent studies indicate that the gastrointestinal symptoms presented by patients with functional bowel disorder improve by restricting the intake of short-chain carbohydrates (Fermentable Oligosaccharides, Disaccharides and Monosaccharides and Polyols: FODMAPs). Objectives: l. Evaluate the efficacy of a diet low in FODMAPs for the improvement of most gastrointestinal symptoms in patients with functional bowel disorder and patients with organic gastrointestinal disorders. 2. Examine the foods within each group of carbohydrates (fructans, galactans, lactose, excess of fructose and polyols) that the patients can again tolerate, after following a diet of reintroducing foods with FODMAPs. Method: Prospective study of 164 patients consecutive with functional bowel disorder attending the Nutrition Unit of a Spanish university hospital. The symptoms presented were abdominal pain, bloating, wind, diarrhoea and/or constipation. Patients followed for 6-8 weeks a diet low in FODMAPs, analysing in every case the improvement and adherence to the dietary treatment. They subsequently followed a re-introductory diet of nutrients with FODMAPs, evaluating their tolerance to each one of the food items. Results: Eighty-four percent of the patients showed an improvement in the gastrointestinal symptoms with a high level of adherence to the dietary treatment. After performing the reintroduction diet, more than 80% of the patients tolerated again wheat as well as dairy products with lactose and more than 70%, legumes and 2 pieces of low-fructose fruits together. Conclusions: 1.The diet low in FODMAPs is effective in improving the gastrointestinal symptoms of patients with functional bowel disorder. 2. Greater adherence to the diet is associated with a general improvement in the gastrointestinal symptoms. 3. The majority of the patients, after following the re-introductory phase, tolerated again wheat, milk, dairy products with lactose and legumes, as well as a variety of fruits with high FODMAPs content (AU)

Carbon dioxide vs. air insufflation in ileo-colonoscopy and in gastroscopy plus ileo-colonoscopy: a comparative study.

INTRODUCTION: insufflation with carbon dioxide (CO2) during endoscopies compared to air is associated with a decrease in abdominal discomfort after the examination, because CO2 is readily absorbed through the small intestine and eliminated by the lungs. AIM: the objective of this randomized clinical trial was to assess the effect of CO2 insufflation on pain and abdominal distension after an ileo-colonoscopy (I) and after an ileo-colonoscopy plus gastroscopy (I+G). MATERIAL AND METHODS: we included a total of 309 patients in the study and all endoscopies were performed under sedation with propofol. Two hundred fourteen patients underwent an I (132 with CO2 / 82 with air) and 95 underwent an I+G (53 with CO2 / 42 with air). Abdominal pain was studied at 10, 30 and 120 minutes of exploration and abdominal perimeter difference before and after the procedure. RESULTS: both in group I and in group I+G, the use of CO2 translated into an average of abdominal pain significantly lower (p < 0.05). Similarly, a smaller increase in waist circumference was found among group I and group I+G, in patients where CO2 was used (p < 0.05). CONCLUSION: the insufflation of CO2 instead of air during the performance of endoscopy significantly reduces the discomfort and abdominal pain after an ileo-colonoscopy and after a gastroscopy + ileo-colonoscopy.

Insuflación de CO2 vs. aire en íleo-colonoscopia y en gastroscopia más íleo-colonoscopia: estudio comparativo / Carbon dioxide vs. air insufflation in ileo-colonoscopy and in gastroscopy plus ileo-colonoscopy: a comparative study

Introducción: la insuflación con dióxido de carbono (CO2) durante las endoscopias digestivas comparado con el aire, se asocia a una disminución de las molestias abdominales después de la exploración, ya que el CO2 es fácilmente absorbido por el intestino delgado y eliminado por los pulmones. Objetivo: el objetivo de este ensayo clínico aleatorizado fue valorar el efecto de la insuflación de CO2 sobre el dolor y la distensión abdominal después de una ileo-colonoscopia (I) y después de una íleo-colonoscopia + gastroscopia (I+G). Material y métodos: se incluyeron un total de 309 pacientes en el estudio y todas las endoscopias fueron realizadas bajo sedación con propofol. A 214 pacientes se les realizó una I (132 con CO2 / 82 con aire) y a 95 se les realizó una I+G (53 con CO2 / 42 con aire). Se estudió el dolor abdominal a los 10, 30 y 120 min de la exploración y la diferencia de perímetro abdominal antes y después del procedimiento. Resultados: tanto en el grupo I como en el grupo I+G, se objetivó una media de dolor abdominal en los pacientes en los que se utilizó CO2 significativamente menor que en los que se utilizó aire (p < 0,05). Y de igual modo se objetivó un menor incremento en el perímetro abdominal para el grupo I y para el I+G en los pacientes en que se utilizó CO2 frente a los que se utilizó aire (p < 0,05). Conclusión: la insuflación de CO2 en vez de aire durante la realización de la exploración endoscópica, reduce significativamente el disconfort y el dolor abdominal después de una íleo-colonoscopia y después de una íleo-colonoscopia + gastroscopia(AU)

Introduction: insufflation with carbon dioxide (CO2) during endoscopies compared to air is associated with a decrease in abdominal discomfort after the examination, because CO2 is readily absorbed through the small intestine and eliminated by the lungs. Aim: the objective of this randomized clinical trial was to assess the effect of CO2 insufflation on pain and abdominal distension after an ileo-colonoscopy (I) and after an ileo-colonoscopy plus gastroscopy (I+G). Material and methods: we included a total of 309 patients in the study and all endoscopies were performed under sedation with propofol. Two hundred fourteen patients underwent an I (132 with CO2 / 82 with air) and 95 underwent an I+G (53 with CO2 / 42 with air). Abdominal pain was studied at 10, 30 and 120 minutes of exploration and abdominal perimeter difference before and after the procedure. Results: both in group I and in group I+G, the use of CO2 translated into an average of abdominal pain significantly lower (p < 0.05). Similarly, a smaller increase in waist circumference was found among group I and group I+G, in patients where CO2 was used (p < 0.05). Conclusion: the insufflation of CO2 instead of air during the performance of endoscopy significantly reduces the discomfort and abdominal pain after an ileo-colonoscopy and after a gastroscopy + ileo-colonoscopy(AU)

¿Presentan un desplazamiento hacia segmentos más proximales los adenomas metacrónicos en el cáncer colorrectal? / Do metachronous colorectal adenomas show proximal shift?

ObjetivoEstudiar en el cáncer colorrectal (CCR) la posibilidad de un desplazamiento hacia segmentos más proximales de los adenomas metacrónicos tras la extirpación del tumor y sus lesiones sincrónicas.Material y métodosRevisamos 382 CCR resecados, diagnosticados y controlados evolutivamente mediante colonoscopias completas. Comparamos la localización de los adenomas metacrónicos con respecto a los sincrónicos globalmente y según el sexo, el tamaño y el número de las lesiones sincrónicas. Analizamos la frecuencia de localización exclusivamente proximal en los adenomas metacrónicos de primera, segunda y tercera generación y la comparamos con la de los adenomas sincrónicos.ResultadosUn 54,5% de los pacientes con CCR presentó adenomas sincrónicos. Tras una mediana de seguimiento de 48 meses, con 2,74±1,47 colonoscopias/caso, el 42,4% desarrolló adenomas metacrónicos, el 16,8% desarrolló adenomas de segunda generación y el 7,3% desarrolló adenomas de tercera generación. Registramos un desplazamiento proximal de los adenomas metacrónicos en ambos sexos, independientemente del tamaño y del número de las lesiones iniciales. La frecuencia de localización exclusivamente proximal de los adenomas fue sincrónico=21,2%; primera generación de metacrónicos=39,5% (p=0,0001; OR=2,46 [1,50–3,95]); segunda generación=42,6% (p=0,0008; OR=2,77 [1,44–5,31]) y tercera generación=39,3% (p=0,0003; OR=2,41 [0,97–5,93]).ConclusionesRegistramos una elevada incidencia de adenomas sincrónicos y metacrónicos. Observamos un «giro proximal» de los adenomas metacrónicos, independientemente del sexo y del tamaño y el número de las lesiones sincrónicas. Esta tendencia se mantiene en las sucesivas generaciones de adenomas metacrónicos, lo que obliga a efectuar colonoscopias completas durante todo el seguimiento postoperatorio(AU)

ObjectiveTo study the possibility of shift toward more proximal sites in colorectal cancer (CRC) after resection of tumors and synchronous lesions.Material and methodsWe reviewed 382 resected CRC diagnosed and followed-up with complete colonoscopies. The localization of metachronous adenomas was compared with that of synchronous lesions overall and by sex, tumoral size and the number of synchronous lesions. The frequency of exclusively proximal localization in first-, second- and third-generation metachronous adenomas was compared with that of synchronous adenomas.ResultsA total of 54.5% of patients with CRC had synchronous adenomas. After a median follow-up of 48 months, with 2.74±1.47 colonoscopies/case, 42.4% developed metachronous adenomas, 16.8% second-generation adenomas and 7.3% third-generation lesions. Proximal shift was found in metachronous adenomas in both sexes, independently of tumoral size and the number of initial lesions. The frequency of exclusively proximal localization in adenomas was 21.2% in synchronous lesions, 39.5% in first-generation metachronous adenomas (p=0.0001; OR=2.46 [1.50–3.95]), 42.6% in second-generation metachronous adenomas (p=0.0008; OR=2.77 [1.44–5.31]) and 39.3% in third-generation metachronous lesions (p=0.0003; OR=2.41 [0.97–5.93]).ConclusionsWe found a high incidence of synchronous and metachronous adenomas. Metachronous adenomas showed a proximal shift, independently of sex, tumoral size and the number of synchronous lesions. This tendency was maintained in successive generations of metachronous adenomas, thus demonstrating the need to perform complete colonoscopies throughout the postoperative follow-up period(AU)

[Do metachronous colorectal adenomas show proximal shift?]. / ¿Presentan un desplazamiento hacia segmentos más proximales los adenomas metacrónicos en el cáncer colorrectal?

OBJECTIVE: To study the possibility of shift toward more proximal sites in colorectal cancer (CRC) after resection of tumors and synchronous lesions. MATERIAL AND METHODS: We reviewed 382 resected CRC diagnosed and followed-up with complete colonoscopies. The localization of metachronous adenomas was compared with that of synchronous lesions overall and by sex, tumoral size and the number of synchronous lesions. The frequency of exclusively proximal localization in first-, second- and third-generation metachronous adenomas was compared with that of synchronous adenomas. RESULTS: A total of 54.5% of patients with CRC had synchronous adenomas. After a median follow-up of 48 months, with 2.74+/-1.47 colonoscopies/case, 42.4% developed metachronous adenomas, 16.8% second-generation adenomas and 7.3% third-generation lesions. Proximal shift was found in metachronous adenomas in both sexes, independently of tumoral size and the number of initial lesions. The frequency of exclusively proximal localization in adenomas was 21.2% in synchronous lesions, 39.5% in first-generation metachronous adenomas (p=0.0001; OR=2.46 [1.50-3.95]), 42.6% in second-generation metachronous adenomas (p=0.0008; OR=2.77 [1.44-5.31]) and 39.3% in third-generation metachronous lesions (p=0.0003; OR=2.41 [0.97-5.93]). CONCLUSIONS: We found a high incidence of synchronous and metachronous adenomas. Metachronous adenomas showed a proximal shift, independently of sex, tumoral size and the number of synchronous lesions. This tendency was maintained in successive generations of metachronous adenomas, thus demonstrating the need to perform complete colonoscopies throughout the postoperative follow-up period.