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Resumen Introducción: La resección anterior ultrabaja interesfintérica (RAUBIE), permite preservar la función esfinteriana en pacientes seleccionados con cáncer de recto (CR). No obstante, puede producir alteraciones en la función evacuatoria y esfinteriana. Objetivo: Analizar los resultados oncológicos y funcionales luego de una RAUBIE. Material y Método: Estudio observacional, analítico, transversal, durante el período 2007 a 2016. Criterios de inclusión: Pacientes sometidos a RAUBIE por CR con intención curativa. Todos los pacientes tuvieron un seguimiento el año 2017. Para la evaluación funcional se usó la escala de Jorge-Wexner, LARS y Kirwan. Análisis estadístico: Estadística descriptiva y método de Kaplan-Meier. Resultados: De 21 pacientes; catorce (67%) fueron varones, edad promedio: 59 años. Ubicación tumoral: 4 cm (2-6 cm) del margen anal. Dieciocho (85,7%) pacientes recibieron neoadyuvancia. Todos los márgenes quirúrgicos distales y radiales fueron negativos. Un paciente (4,8%) tuvo metástasis a distancia y no hubo recurrencia locorregional. Con una mediana de seguimiento de 76,3 (9,8-126,8) meses, la sobrevida global y libre de enfermedad a 5 años fue de: 100% y 95% (IC: 90,1-99,9%), respectivamente. Con una mediana de seguimiento de 90 meses (21,7-124,2); se realizó la evaluación funcional a 15/21 pacientes. El puntaje de Jorge-Wexner tuvo una mediana de 13 (4-17) puntos, la escala de LARS de 34 puntos y en la escala de Kirwan, cuatro pacientes (26,7%) mostraron una buena función (Kirwan I-II). Conclusión: Si bien los resultados oncológicos de los pacientes sometidos a una RAUBIE son satisfactorios, se debería tomar en cuenta los resultados funcionales al momento de proponer esta alternativa quirúrgica. Introduction: Intersphinteric resection (ISR) allows preserve sphincter function in selected patients with rectal cancer (RC). Notwithstanding, it can produce alterations in defecation. Aim: To analyze the oncological and functional results after an ISR. Materials and Method: Observational, analytical, cross-sectional study, in the period 2007-2016. Inclusion criteria: Patients submitted to ISR by RC with curative intention. All the patients had a follow-up in 2017. Analysis of functional evaluation were performed by Jorge-Wexner, LARS and Kirwan scale. Statistical analysis: Descriptive statistics and Kaplan-Meier method. Results: Of 21 patients; Fourteen (67%) were male, average age: 59 years. Tumor location: 4 cm (2-6 cm) from anal verge. Eighteen (85.7%) patients received neoadjuvant therapy. All distal and radial margins were negative. One patient (4.8%) had distant metastases and there was no locoregional recurrence. With a median follow-up of 76.3 (9.8-126.8) months, the 5-year global and disease-free survival was: 100% and 95% (CI: 90.1-99.9%), respectively. With a median follow-up of 90 months (21.7-124.2); Functional evaluation was performed on 15/21 patients. The Jorge-Wexner score had a median of 13 (4-17) points, the LARS scale of 34 points and in Kirwan scale, four patients (26.7%) showed good function (Kirwan I-II). Conclusion: The oncological results of patients undergoing ISR are satisfactory, however, functional results should be taken into account when proposing this surgical procedure.

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.

Background: Primary non-response and secondary loss of response (LOR) are significant problems of biological therapy for inflammatory bowel disease (IBD). Therapeutic drug monitoring (TDM) in IBD patients receiving these drugs can improve outcomes. Aim: To measure serum infliximab levels and anti-infliximab antibodies (ATI) in patients with IBD post-induction phase and during maintenance therapy assessing the clinical course of IBD. Patients and Methods: Prospective study of IBD patients receiving infliximab between July 2016-May 2017. Group-A included patients who received induction therapy while Group-B included patients who were in maintenance therapy. TDM was performed in serum samples collected at weeks-14 and 30 in Group-A and before the infliximab maintenance dose in Group-B. Clinical scores, fecal calprotectin and endoscopic score were also evaluated. Results: Of 14 patients in Group-A, 57% achieved endoscopic response. Median serum infliximab concentrations at week-14 and 30 were 2.65 AU/mL (0.23-32.58) and 2.3 AU/mL (0.3-16.8), respectively. Patients with mucosal healing had non-significantly higher median infliximab concentrations at week- 14, as compared to week 30 (median 3.2 vs 2.2 AU/ml, respectively, p 0.6). ATI >10 ug/mL were found in one and seven patients at week-14 and 30, respectively. At 52 weeks of follow-up, four patients (31%) had LOR. Group-B included 36 patients, 33% had LOR. Median serum concentrations of infliximab were 1.4 AU/mL (0.27-7.03). No significant differences in serum infliximab concentration were observed between patients in remission and those with inflammatory activity. Seventeen patients had ATI >10 ug/mL. Conclusions: Clinical algorithms using TDM might help to optimize the pharmacological therapy of IBD.

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.

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.

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.

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.

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 α4β1 and α4β7 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.

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.

Benign multicystic peritoneal mesothelioma is an uncommon lesion arising from the peritoneal mesothelium. It is asymptomatic or presents with unspecific symptoms. Imaging techniques may reveal it, however the final diagnosis can only be made by histopathology. Surgery is the only effective treatment considering its high recurrence rate. We report a 19 years old male with Crohn’s disease. Due to persistent abdominal pain, an abdominal magnetic resonance imaging was performed, showing a complex cystic mass in the lower abdomen. The patient underwent surgery and the lesion was completely resected. The pathological study reported a benign multicystic peritoneal mesothelioma.

Objetivo: Analizar la frecuencia y tipo de tumores asociados en pacientes con poliposis adenomatosa familiar clásica (PAFc) sometidos a una colectomía profiláctica. Materiales y Métodos: Estudio de cohorte. Desde el registro de cáncer colorrectal (CCR) hereditario, se identificaron las familias con PAFc, y de estas a los pacientes que se les practicó una colectomía total con anastomosis íleorrectal (CT-AIR) o proctocolec-tomía restauradora (PCTR), desde 1999 al 2014. En el seguimiento se analizaron los tumores asociados y su mortalidad. Resultados: Se identificaron 27 pacientes, de los cuales 18 (66,7%) fueron sometidos a CT-AIR y 9 (33,3%) a PCTR. Al momento de la cirugía, 4 pacientes presentaban CCR (15%) y 5 tenían tumores extracolónicos (osteomas). En un seguimiento promedio de 49,4 meses (i: 2 y 178) se diagnosticaron: adenomas del tracto digestivo en 17 (63%) pacientes, de éstos 2 requirieron una proctectomía y 3 resecciones de adenomas duodenales. Ocho pacientes desarrollaron tumores desmoides (30%), y 3 de ellos fueron sometidos a una cirugía. Un paciente presentó un tumor extradigestivo (cáncer de tiroides) y sólo 8/27 (29,6%) pacientes no desarrollaron otros tumores. Un paciente falleció por progresión de su CCR. Discusión: En esta serie se confirma que la mayoría de los pacientes con PAFc seguirán desarrollando neoplasias después de su colectomía. conclusiones: La extirpación del colon y/o recto permitió evitar el desarrollo de CCR. Sin embargo, dos tercios de los pacientes presentaron otros tumores en quienes su seguimiento permitió una detección y tratamiento temprano. phenotypic expression is the presence of múltiple colorectal adenomatous polyps (more than 100), with high probability developing colorrectal cancer (CRC) before the fifth decade of life. Prophylactic surgery (total colectomy or restorative proctocolectomy) reduces the risk of developing CRC. However, the risk of developing tumors in other organs remains present. Objetive: Analyze the frequency and type of tumors associated with classic familial adenomatous polyposis syndrome (FAPc) patients undergoing prophylactic colectomy. Material and Methods: Cohort study. From the registry of hereditary colorrectal cancer (CRC) at our institution, we identified patients with FAPc who underwent total colectomy with ileorrectal anastomosis (TC-IRA) or restorative proctocolectomy (RTPC), from 1999 to 2014. In the follow-up we analyzed related tumors and mortality. Results: 27 patients, of whom 18 (66.7%) underwent TC-IRA and 9 (33.3%) underwent RTPC. At the time of surgery, 4 patients had CRC (15%) and 5 had extracolonic tumors (osteomas). In a mean follow-up of 49, 4 months (i: 2 y 178) the following lesions were diagnosed: digestive tract adenomas in 17 (63%) patients, of these 2 required a proctectomy and 3 resection of duodenal adenomas. Eight patients developed desmoid tumors (30%), and 3 of them underwent surgery. One patient had an extradigestive tumor (thyroid cancer) and only 8/27 (29.6%) did not develop other tumors. One patient died due to progression of his CCR. Discussion: In this series it is confirmed that most patients will develop neoplasms FAPc after colectomy. conclusion: The removal of the colon and/or rectum is able to prevent the development of CRC. However, two thirds of the patients develop other tumors in which systematic surveillance allowed early detection and treatment.

Background: The chronic inflammation of the intestinal mucosa, the extra-intestinal manifestations of the disease and the immunosuppressive treatment of inflammatory bowel disease may increase cancer risk. Aim: To report the demographic and clinical features of patients with IBD who developed a malignant tumor. Material and Methods: Retrospective analysis of an IBD patient registry of a private clinic, diagnosed between 1976 and 2014. Results: 437 subjects were included, aged 15-88 years (58% women). Seventy two percent of patients had ulcerative colitis. The median time of follow up was 6 years. Ten patients (2.3%) developed a malignant tumor. In four, the tumor could be related to IBD (two colorectal cancers, one cholangiocarcinoma and one chronic myeloid leukemia (CML)). Two of 45 patients treated with biological therapy developed a tumor (CML and hypernephroma). Three of 170 patients on immunosuppressive treatment developed tumors. Only one had a tumor possibly related with the use of azathioprine (non-melanoma skin cancer). In only two patients, the treatment was changed at the time of their cancer diagnosis, from immunosuppressive medications to mesalamine. Conclusions: Only a small proportion of these patients with IBD developed a malignant tumor. The treatment of IBD has to be determined by the severity of the disease and not by the fear of developing a neoplasia. Following recommendations is fundamental to decrease the possibility of developing this complication.

Background: Approximately, 15% of patients with Inflammatory Bowel Disease (IBD) are diagnosed at 60 years of age or more. Aim: To characterize and compare clinical variables between patients with IBD aged 60 years or more and their younger counterparts. Material and Methods: Retrospective study based on a registry of IBD patients diagnosed between the years 1976 and 2014. Results: Four hundred and nine IBD patients were included. Among them, 294 had Ulcerative Colitis (UC), 104 had Crohn's Disease (CD) and eleven had an indeterminate IBD. Forty-six patients (11.2%) were older than 60 years and 16 (3.9%) had been diagnosed after this age. When comparing patients by age, those aged 60 years or more had a higher frequency of CD and indeterminate IBD (p < 0.01) and a lower ileocolic location in CD (p = 0.02). Both groups were similar in terms of hospitalization due to IBD flare, surgery, use of steroids, immunosuppressive or biological therapies and drug-related adverse events. When analyzing age at diagnosis of IBD, patients diagnosed at ages of 60 years or more had a lower frequency of UC (p < 0.01), a higher frequency of exclusive colonic involvement (p = 0.01), and lower use of mesalamine (p < 0.01). There were no differences in drug-related adverse events, hospitalizations due to IBD flares and surgery according to age at diagnosis. Conclusions: In this population, clinical features of IBD in older patients were similar to those in younger patients.

Introducción: En el cáncer colorrectal (CCR), se sugiere que un mejor pronóstico podría asociarse a una respuesta inmune antitumoral (del huésped) y/o a la presencia de una alta inestabilidad microsatelital (MSI). Objetivo: Determinar si los niveles de expresión de los marcadores de linfocitos T (CD3/CD4/CD8/ CD45RO/FoxP3) y el estado de MSI se asocian a estadios metastásicos en pacientes con CCR. Material y Método: Estudio prospectivo de 109 pacientes con diagnóstico de CCR. El análisis de expresión de los marcadores CD3/CD4/CD8/CD45RO/FoxP3 fue realizado por inmunohistoquímica; los tumores fueron clasificados en negativo, débil e intenso. La MSI fue evaluada con siete marcadores amplificados desde ADN normal y tumoral; los tumores fueron agrupados en: MSS (estable)/MSI-baja y MSI-alta. El análisis estadístico fue realizado con el test exacto de Fischer. Resultados: Una intensa expresión de los marcadores CD3+, CD4+, CD8+ y CD45RO+, fue observada en el 29%, 28%, 12% y 86% de los tumores, respectivamente. El 16% de los tumores presentó MSI-alta. Los tumores que presentan una alta densidad de linfocitos T (CD3+, CD4+ y CD45RO+) se asocian a estadios tempranos I-II (p = 0,023; p = 0,030 y p = 0,003, respectivamente). Adicionalmente, se identificó una asociación estadística significativa entre los tumores con MSS/MSI-baja y una menor capacidad de reclutar linfocitos T citotóxicos CD8+ (p = 0,037) y totales CD3+ (p = 0,064). Conclusión: Existe una asociación entre altas densidades de linfocitos T CD3+, CD4+ y CD45RO+ y tumores con estadios no metastásicos. Además, tumores con MSS/MSI-baja se asocian a un menor reclutamiento de linfocitos T CD8+ y CD3+. Background: In colorectal cancer (CRC) patients, lymphocyte infiltration (LI) and microsatellite instability (MSI) have been associated with better prognosis. Aim: To analyze the association between components of LI (CD3/CD4/CD8/CD45R0/FoxP3) and MSI status with metastatic stages in CRC patients. Material and Methods: Prospective study of 109 patients diagnosed with CRC. The expression of CD3, CD4, CD8, CD45R0 and FoxP3 markers, was evaluated by immunohistochemical analysis, and tumors were classified into negative, low and intense expression. The MSI was assessed with seven markers amplified by PCR from normal and tumoral DNA. Tumors were grouped in MSS (stable)/MSI-low and MSI-high. Statistical analysis was performed with Fischer's exact test. Results: 29%, 28%, 12% and 86% of tumors exhibits intense expression of CD3+, CD4+, CD8+ and CD45RO+ lymphocytes, respectively. 84% of the tumors presented MSS/ MSI-low and 16% had MSI-high. Tumors that show a high density of T cells (CD3+, CD4+ y CD45R0+) are associated with early stage tumors (I and II) (p = 0.023; p = 0.030 and p = 0.003, respectively). Additionally, there was a significant association between the MSS/MSI-low tumors and a reduced ability to recruit CD8+ cytotoxic T lymphocytes (p = 0.037) and CD3+ (p = 0.064). Conclusion: There is an association between high densities of CD3+, CD4+ and CD45RO+ lymphocytes and non-metastatic tumors. In addition, MSS/ MSI-low tumors are associated with a lower recruitment of CD8+ and CD3+ lymphocytes.

Background: The molecular testing of KRAS mutation status in metastatic colorectal cancer patients is mandatory to identify patients eligible for anti-epidermal growth factor receptor monoclonal antibody therapy. Aim: To report the frequency of KRAS gene mutations in Chilean patients with colorectal cancer (CRC). Material and Methods: A cohort of 262 Chilean patients with CRC aged 26 to 90 years (53% males), was studied. KRAS mutation status was analyzed by real-time polymerase chain reaction and correlated with clinicopathological data. Results: Ninety-eight patients (37%) were positive for KRAS mutations. G12D was the most common mutation with a frequency of 36.7%, followed by G12V (25.5%), G13D (17.3%), G12A (7.1%), G12C (6.1%), G12S (5.1%) and G12R (2%). The frequency of the mutation in left, right colon and rectal tumors was 37.8, 32.6 and 44.9%, respectively. Among tumors with mutations, 86.7% were well or moderately differentiated tumors and the rest were poorly differentiated. No significant associations between KRAS gene mutations and other clinicopathological features of the tumor were observed. Conclusions: The frequencies of KRAS mutations reported in this study are similar to frequencies reported for European and North-American populations, lower than in a Spanish study and higher than in a Peruvian study.

Background: The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased. Aim: To determine demographic and clinical characteristics of patients with IBD in a Chilean private hospital. Patients and Methods: Review of a prospective registry of patients with IBD, started on 2012. It includes clinical, imaging, endoscopical and pathological information of patients. Results: Data of 316 patients with IBD, aged 16 to 86 years (56% females), were analyzed. Ulcerative Colitis (UC), Crohn´s and non-classifiable IBD were diagnosed in 230, 77 and 9 patients, respectively. The disease was diagnosed in 82% of patients in the period between 2002 and 2012. There was a peak in the diagnosis of both UC and CD between 20 and 39 years of age, without gender differences. The disease switched from UC to CD in six patients. In four, there was a change in disease behavior. Thirty eight patients were treated with biological therapy. The median lapse between the diagnosis and the use of biological therapy was 1 year in patients diagnosed after 2007, compared with 5.5 years among those patients diagnosed before 2007 (p = 0.001). There was a trend towards a higher requirement of surgery until 2006. Subsequently there was a stabilization of the requirement, concomitant with the incorporation of biological therapy. Conclusions: An adequate registry of IBD patients is necessary to improve demographic and clinical characteristics. A national registry is needed to assess the epidemiological changes of IBD in Chile.

Background: The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased. Aim: To determine demographic and clinical characteristics of patients with IBD in a Chilean private hospital. Patients and Methods: Review of a prospective registry of patients with IBD, started on 2012. It includes clinical, imaging, endoscopical and pathological information of patients. Results: Data of 316 patients with IBD, aged 16 to 86 years (56% females), were analyzed. Ulcerative Colitis (UC), Crohn´s and non-classifiable IBD were diagnosed in 230, 77 and 9 patients, respectively. The disease was diagnosed in 82% of patients in the period between 2002 and 2012. There was a peak in the diagnosis of both UC and CD between 20 and 39 years of age, without gender differences. The disease switched from UC to CD in six patients. In four, there was a change in disease behavior. Thirty eight patients were treated with biological therapy. The median lapse between the diagnosis and the use of biological therapy was 1 year in patients diagnosed after 2007, compared with 5.5 years among those patients diagnosed before 2007 (p = 0.001). There was a trend towards a higher requirement of surgery until 2006. Subsequently there was a stabilization of the requirement, concomitant with the incorporation of biological therapy. Conclusions: An adequate registry of IBD patients is necessary to improve demographic and clinical characteristics. A national registry is needed to assess the epidemiological changes of IBD in Chile.

Recently, MUTYH mutations have been reported to predispose to the development of polyposis. However, polyposis caused by mutations in MUTYH has been characterized as an autosomal recessive hereditary disease, different from the autosomal dominant pattern observed in polyposis caused by APC mutations. We report a 41-year-old female consulting for anemia. Colonoscopy detected multiple sessile polyps and a cecal carcinoma. The patient was operated and in the surgical piece, the tumor invaded serosa and there was lymph node involvement. Approximately 100 polyps were found. The patient received 5-fluorouracil, as adjuvant therapy. The patient had a sister (of a total of 12 brothers) with a colorectal carcinoma. The genetic study identified a homozygous mutation of the MUTYH gene, called c.340T > C, that produces an amino acid change of tyrosine for histidine called p.Y114H. The sister with colorectal cancer was a heterozygous carrier of this mutation.

Background: Selection of patients with Lynch Syndrome (LS) for a genetic study involves the application of clinical criteria. To increase the rate of identification of mutations, the use of molecular studies as Microsatellite Instability (MSI) and Im-munohistochemistry (IHC) in the tumor has been proposed. Aim: To demonstrate the usefulness of MSI and IHC in the detection of mutations in patients with LS. Material and Methods: From our Familial Colorectal Cancer Registry, families suspected of LS were selected according to Amsterdam or Bethesda clinical criteria. Screening of germline mutations of MLH1, MSH2 and MSH6 genes was performed. In addition, analysis of MSI and IHC were performed in colorectal tumors. Results: A total of 35 families were studied (19 met Amsterdam and 16 met Bethesda criteria). Twenty one families harbored a germline alteration in MLH1, MSH2 or MSH6 (18 Amsterdam and 3 Bethesda). In these families, eighteen different alterations were found, 15 of which were mutations and 3 corresponded to variants of uncertain pathogenicity. On the other hand, 80% of the tumors showed positive microsatellite instability (27 MSI-high and 1 MSI-low), and immunohistochemical testing showed that 77% of tumors had the loss of a protein. Correlation between results of tumor molecular studies and the finding of germline nucleotide change showed that IHC and MSI predicted mutations in 81 and 100% of patients, respectively. Conclusions: MSI and IHC can efficiently select patients with a high probability of carrying a mutation in DNA repair genes.

Posterior al advenimiento de Ia cirugia laparoscópica colorrectal, desde comienzos de Ia década de Ios 90, se han desarrollado diversos tipos de accesos minimamente invasivos, siendo hoy en dia el acceso por un puerto único una alternativa factible. Se presenta el caso clínico de una paciente de 55 años, a Ia cual por sintomatologia se Ie diagnóstica una lesión rectal, Ia que luego de ser estudiada endoscópica y endosonográ-ficamente, es resecada por monopuerto via anal. La cirugia duró 45 minutos y no presentó eventos adversos intraoperatorios. Su evolución quirúrgica fue satisfactoria con alta hospitalaria al dia siguiente de Ia cirugia. Single port access for minimally invasive surgery is feasible nowadays. We report a 55 years old female presenting with hematochezia. During a colonoscopy, a villous adenoma of 2 cm in diameter located 5 cm above the anal margin, was found. This lesion was excised through the anus, using a single port trocar. The procedure lasted 45 minutes, the postoperative evolution was uneventful and the patient was discharged 24 hours after the procedure.

Introducción: La patología hemorroidal es una condición muy frecuente en la población general y aproximadamente un 10% de los afectados requerirá cirugía. Existen distintas técnicas para su abordaje, siendo la operación de Longo o PPH (procedimiento para el prolapso y las hemorroides) una alternativa que ha cobrado relevancia. Existe poca evidencia de los resultados desde el punto de vista de la satisfacción de los pacientes. El objetivo de nuestro trabajo es dar a conocer la evaluación y percepción de los pacientes operados de hemorroides con la técnica de PPH en un seguimiento a mediano plazo. Material y Métodos: Se identificaron todos los pacientes operados con la técnica de PPH entre enero de 2007 y enero de 2009. Se aplicó una encuesta diseñada para consignar la presencia de algunos síntomas antes y después de la cirugía. Resultados: 57 pacientes completaron la encuesta, con un seguimiento promedio de 17,6 meses (extremos 8-31). Un 94% de los pacientes refirió la desaparición del sangrado, el 85% del prolapso hemorroidal y un 68% del ensuciamiento (soiling) tras la intervención. En una escala de evaluación de 1 a 7, el 88% de los pacientes calificó el procedimiento con nota > 5 y el 87% recomendaría el uso de esta técnica a otros pacientes afectados por esta patología. Conclusión: El uso de la técnica de PPH es evaluada favorablemente por la mayoría de los pacientes en relación a la resolución de sus síntomas, al estado funcional y al grado de satisfacción en un seguimiento postoperatorio a mediano plazo. Background: Hemorrhoidal disease is very common and approximately 10% of the patients require surgery. Within the different surgical techniques, the Longo procedure or PPH (procedure for prolapse and hemorrhoids) has gained importance. Aim: To evaluate the patients' perception of PPH hemorrhoidectomy in a medium term follow-up. Material and Methods: All patients undergoing PPH hemorrhoidectomy between January 2007 and January 2009 were identified. A survey was designed to assess the presence of specific symptoms before and after surgery, and applied to all patients. Results: Fifty-seven patients completed the survey, with a follow-up ranging from 8 to 31 months. Ninety-four percent of patients referred improvement of bleeding, 85% of hemorrhoidal prolapse and 68% of soiling after the intervention. On a scale of 1 to 7, 88% of patients rated the procedure with a score over 5, and 87% would recommend the use of this technique to other patients suffering from the disease. Conclusions: Most patients favorably assess PPH hemorrhoidectomy in terms of postoperative resolution of the symptoms, functional status and overall satisfaction in a medium-term follow-up.

The laparoscopic approach is an alternative for the elective treatment of diverticular colon disease (DCD). Aim: To analyze the results of patients electively operated for DCD using a laparoscopic technique. Material and Methods: Data of patients with DCD operated using laparoscopy at the Catholic University of Chile Clinical Hospital were prospectively recorded from January 1999 to August 2006. Indications for surgery were repetitive crises of acute diverticulitis, the persistence of the symptoms or anatomic deformity after the first crisis and complicated diverticulitis (Hinchey 1-2) that responded to the medical treatment. The laparoscopic technique used five ports and the surgical specimen was extracted through a suprapubic approach. Results: One hundred and six patients aged 32 to 82 years (49% females) were operated in the study period. Fifty five percent had a previous abdominal surgery. The mean operative time was 213 minutes (range: 135-360). Four patients were converted to open surgery (3.7%). One or more early post-operative complications were observed in five patients (4.7%). The mean time for passing gases and reinitiate liquid diet was 1.7 and 2.4 days respectively. The median post operative stay after surgery was 4 days. There was no operative mortality. Mean follow-up time was 27 months and only one patient (0.9%) had a new episode of acute diverticular disease, with a satisfactory response to medical treatment. No patient has developed bowel obstruction. Conclusions: The laparoscopic approach is a safe alternative in the elective surgical treatment of DCD

Objetivo: Comparar resultados y complicaciones inmediatas al realizar una sigmoidectomía lapa-roscópica (SL) versus abierta (SA) en pacientes con cáncer de colon sigmoides. Material y método: Inclusión prospectiva y consecutiva, mediante protocolo de estudio de pacientes operados mediante SL entre el 2000 y el 2006. Análisis comparativo caso-control, mediante pareo según edad, sexo y ASA entre pacientes operados mediante SL con SA. Análisis por intención de tratamiento, mediante test t de Student, chi cuadrado, Mann-Withney y exacto de Fischer; consideramos estadísticamente significativo p 0,05). La mediana del tiempo operatorio fue mayor en SL (220 v/s 172 minutos, p 0.5). The mean operative time was higher in LS group (220 v/s 172 minutes, p

Background: First degree relatives of patients with colorectal carcinoma are at a higher risk of having the disease than the general population. Therefore, they should be subjected to screening colonoscopy. Aim: To assess the effectiveness of colonoscopy among first degree relatives of patients with colorectal carcinoma. Material and methods: A free colonoscopy was offered to first degree relatives of patients operated on for colorectal cancer between 1998 and 2000. As inclusion criteria, subjects had to be asymptomatic, older than 40 years or less than 10 years younger than the index case. Each subject was contacted twice, inviting him/her to have a colonoscopy performed. Results: Two hundred forty three relatives were contacted for the study and in 76, a colonoscopy was performed. Among the latter, a neoplasm was found in 13 (17%): One adenocarcinoma and 12 adenomas. Three of these lesions were located in the right colon. The main reason given by the 176 subjects that did not agree to have a colonoscopy was lack of interest. Conclusions: Screening colonoscopy is effective to detect adenoma and adenocarcinomaamong first degree relatives of patients with colorectal carcinoma, however only 31% of all potential relatives agreed to undergo a colonoscopy (Rev Méd Chile 2006; 134: 997-1001)