Eliana Pinto

Detection of Lymphatic Micrometastases in Patients With Stages I and II Colorectal Cancer: Impact on Five-Year Survival

PURPOSE:Despite having removed the whole macroscopic disease (curative intent surgery), one of five patients with Stages I and II colorectal cancer will develop recurrence. Lymphatic micrometastases detected by immunohistochemistry could be one of explanation for recurrence and cancer-related death in patients without lymph node involvement at light microscopy. However, the biologic importance of micrometastases remains unclear. This study was designed to determine the impact of micrometastases in five-year survival in patients with Stages I and II colorectal cancer.METHODS:This retrospective study included patients operated on between May 1989 and January 1999 for colorectal cancer without histopathologic lymph node involvement. Patients who received any adjuvant therapy were excluded. Immunohistochemical staining of the lymph nodes was performed with antipancytokeratin antibodies. Follow-up data were obtained from the clinical database and death certificates. Survival was estimated by the Kaplan-Meier method and compared by the log-rank test.RESULTS:Micrometastases were observed in 26 of 90 patients (28.9 percent). The mean follow-up time was 90.7 (range, 11–160) months. Seventeen cancer-related deaths occurred during follow-up (18.9 percent), 6 of them in patients with micrometastases (23.1 percent) and 11 in patients without micrometastases (17.2 percent; P = 0.559). Cancer-specific five-year survival was 87 percent in the whole group and 81 percent in patients positive for micrometastases vs. 90 percent in negative patients (P = 0.489).CONCLUSIONS:The presence of micrometastases in patients with Stages I and II colorectal cancer seems not to have any impact on cancer-specific survival.

Síndrome de Lynch: selección de pacientes para el estudio genético mediante análisis de inestabilidad microsatelital e inmunohistoquímica

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 Immunohistochemistry (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.

Programa de detección de neoplasias colorrectales en población mayor de 50 años

BACKGROUND Mortality from colorectal cancer (CCR) in Chile has nearly doubled over the past 15 years. International studies have shown that CCR screening programs based on fecal occult blood test (FOBT) reduce CCR mortality. AIM To analyze the results from a CCR screening model in people over 50 years. MATERIAL AND METHODS Between 2007 and 2009, a prospective multicenter study was performed in seven major Chilean cities. FOBT using an immunological method, was measured in asymptomatic subjects aged 50 years or more, without risk factors. In patients with a positive FOBT, with symptoms or with family risk factors, a colonoscopy was indicated. RESULTS A total of 6348 subjects were assessed, FOBT was performed in 4938 of them, with a compliance of 77%. The result was positive in 9.6%. A total of 2359 colonoscopies were ordered, with an overall compliance of 50.1%. Of the 1184 colonoscopies performed, adenomas and high risk adenomas were found in 304 (26%) and 75 (6%) patients, respectively. Thirteen patients were diagnosed with stage I and IICCR. Three of these lesions were excised endoscopically and 10 surgically. The detection rate of polyps, high risk adenomas and cancer was 75, 12 and 2 per 1000 screened individuals, respectively. CONCLUSIONS This program allowed the early detection of an important number of high risk colon lesions, and all patients with CCR were diagnosed at early stages.

Abstract 2114: Deletions/Duplications detection by MLPA in Chilean families with hereditary colorectal cancer: Lynch syndrome and FAP

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC The main variants of colorectal cancer hereditary are Familial Adenomatous Polyposis (FAP) and Lynch Syndrome, which account for approximately 5% of total cases of colorectal cancer. Point mutations in APC and MMR genes are responsible of about 85% and 50% of Chilean FAP (classic phenotype) and Lynch Syndrome (Amsterdam criteria) families, respectively. Different molecular strategies are available for the detection of mutations in these genes. Studies in other populations have identified deletions and duplications of one or more consecutive exons account for around 50% and 10-20% of the total alterations in MMR and APC genes, respectively. The aim of our work was the detection of genomic deletion/duplication through Multiplex Ligation-Dependent Probe Amplification (MLPA) in Lynch Syndrome and FAP patients in Chile. In this study, we analized alterations in MLH1 and MSH2 in 26 Lynch Syndrome families (5 Amsterdam and 21 Bethesda families), and in APC in 10 FAP families (6 classic and 4 attenuated), all of them non carriers of point mutations in these genes. We identified 3 different alterations in the MLH1 in four Amsterdam families, all of them are 0.5 times deletion, which are located: exon 1 in one family, exon 19 in two families, and exons 14 and 15 in one family. In the MSH2, in one Amsterdam family we detected a 0.5 time deletion of exon 2. In the APC, we found 2 different alterations in three classic FAP families: in one family we detected a 0.5 times deletion of the whole gene including promoter region, and in two families we found a 1.5 time amplification of exons 1, 2 and 3. These alterations were confirmed in other relatives of these families and in two independent MLPA analysis. The deletion of exon 19 in MLH1 and the amplification of exons 1, 2 and 3 in APC have not been previously described in other populations. In conclusion, genomic deletions/duplications were only detected in 5 Lynch Syndrome families that fulfilled Amsterdam criteria, and in 3 FAP families with classic phenotype. The detection of different mutations involved in these syndromes, allows the development of prevention strategies of these diseases. Financed by Cleveland Clinic Foundation and Las Condes Clinic. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2114.

SE JUSTIFICA EL SEGUIMIENTO DESPUÉS DE UNA COLECTOMÍA EN PACIENTES CON POLOPOSIS ADENOMATOSA FAMILIAR

Objetivo: Analizar la frecuencia y tipo de tumores asociados en pacientes con poliposis adenomatosa familiar clasica (PAFc) sometidos a una colectomia profilactica. Materiales y Metodos: Estudio de cohorte. Desde el registro de cancer colorrectal (CCR) hereditario, se identificaron las familias con PAFc, y de estas a los pacientes que se les practico una colectomia total con anastomosis ileorrectal (CT-AIR) o proctocolec-tomia 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 cirugia, 4 pacientes presentaban CCR (15%) y 5 tenian tumores extracolonicos (osteomas). En un seguimiento promedio de 49,4 meses (i: 2 y 178) se diagnosticaron: adenomas del tracto digestivo en 17 (63%) pacientes, de estos 2 requirieron una proctectomia y 3 resecciones de adenomas duodenales. Ocho pacientes desarrollaron tumores desmoides (30%), y 3 de ellos fueron sometidos a una cirugia. Un paciente presento un tumor extradigestivo (cancer de tiroides) y solo 8/27 (29,6%) pacientes no desarrollaron otros tumores. Un paciente fallecio por progresion de su CCR. Discusion: En esta serie se confirma que la mayoria de los pacientes con PAFc seguiran desarrollando neoplasias despues de su colectomia. conclusiones: La extirpacion del colon y/o recto permitio evitar el desarrollo de CCR. Sin embargo, dos tercios de los pacientes presentaron otros tumores en quienes su seguimiento permitio una deteccion y tratamiento temprano.

Abstract 2645: Genomic deletions and point mutations in the STK11 gene in Peutz-Jeghers Chilean families

Background: Peutz-Jeghers syndrome (PJS) is a rare autosomal dominant hereditary disease characterized by mucocutaneous pigmentation and gastrointestinal hamartomatous polyposis. Individuals with PJS are at increased risk for development of various neoplasms. The genetic susceptibility for PJS has been associated with germline mutation in the serine/threonine kinase 11 (STK11) gene. The aim of the present study was to characterize the genotype and phenotype of Chilean PJS patients. Methods: Mutation screening of 13 patients from 8 PJS families was performed by using single strand conformation polymorphism (SSCP) analysis and DNA sequencing, covering the entire coding region and the splice-site boundaries. In addition, multiplex ligation-dependent probe amplification (MLPA) assay was used for the identification of large exonic deletions or duplications. Results: We identified seven different pathogenic mutations in STK11 gene in 7 unrelated families. Point mutations correspond to a small deletion (c.109delC) in exon 1 that generates a premature stop codon and two intronic mutations localized in splice site of intron 4 (c.597+2 T>A) and intron 6 (c.862-2 A>G). The pathogenic effect on splicing of intronic changes was demonstrated in mRNA of STK11 from lymphocytes of patients. By MLPA, we identified four large deletions ranging from one exon to the whole gene. Breakpoints were identified in two of these patients. Three point mutations (43%, 3/7) may be considered as novel. Conclusions: Different germline mutations in STK11 were detected. A combination of sensitive techniques may improve a high STK11 mutation detection frequency (88%) in PJS Chilean families. Funded by Clinica Las Condes Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2645. doi:1538-7445.AM2012-2645

Globalización y salud pública

Conocimiento, actitudes y practicas sobre salud oral en ninos de 12 anos Frecuencia de malos habitos bucales en ninos de 4 a 11 anos de Rancagua Integracion del sistema de salud en Mexico: el caso de la atencion de emergencias obstetricas Modelo de pesquisa de cancer colorrectal. Resultados del proyecto Previcolon 2007-2009 Perfil del paciente dental adulto que acude a la HUAP (Posta Central) Rol de un registro en familiares asintomaticos de pacientes con poliposis adenomatosa familiar Salud de inmigrantes en Chile: observando mas alla del efecto del migrante sano