Factores asociados al pronóstico de pacientes operados por cáncer gástrico avanzado / Pathological factors associated with survival in advanced gastric cancer

Background: The degree of tumor infiltration and lymph node involvement are the most relevant pathological features to determine prognosis of advanced gastric cancer. Aim: To determine the association between clinical and pathological features of advanced gastric cancer and patient survival. Material and Methods: The pathological records of patients with advanced gastric cancer subjected to gastrectomy and lymph node excision between 1986 and 2007 were analyzed. Follow up was performed according to data in the clinical records and death certificates obtained at the Chilean National Death Registry. The main outcome analyzed was survival after surgery. Results: The records of 299 patients aged 62 +/- 11 years (68 percent males), were analyzed. Mean follow up ranged from 1 to 206 months. Five and 10 years actuarial survival was 39 and 34 percent, respectively. The pathological predictors of survival were microscopic tumor stage, tumor size and location, Bormann classification, infiltration level, degree of differentiation, pathological type of tumor according to Lauren, Ming y Nakamura, lymph node involvement and the absence of residual tumor after surgical excision. Conclusions: The pathological study of the surgical piece in advanced gastric cancer has important prognostic implications.

Introducción: El estudio de la pieza operatoria de pacientes resecados por cáncer gástrico (CG) ha permitido identificar variables anatomo-patológicas con valor pronóstico en la supervivencia (SV) y recurrencia de estos pacientes, siendo el compromiso ganglionar linfático y nivel de infiltración tumoral, los factores más relevantes identificados. El objetivo de este estudio es determinar asociación entre variables clínicas y morfológicas con la SV de pacientes resecados por CG avanzado (CGA). Material y Método: Estudio de cohorte retrospectiva. Se estudiaron variables clínicas y morfológicas de 299 pacientes operados por CGA entre enero de 1986-diciembre de 2001. Los datos fueron obtenidos desde la Unidad de Anatomía Patológica del Hospital Hernán Henríquez Aravena de Temuco. Se aplicó estadística descriptiva y analítica; confección de curvas de supervivencia, y finalmente se aplicaron modelos de regresión logística para realizar ajuste, calcular odds ratios y sus respectivos intervalos de confianza de 95 por ciento. Resultados: La cohorte tuvo una mediana de edad de 63 años y el 68 por ciento de ella correspondió al género masculino. Con una mediana de seguimiento de 21 meses (1 a 206), se observó una SV actuarial global a 5 y 10 años de 39 por ciento y 34 por ciento respectivamente. En el análisis bivariado, se verificó asociación con la SV en: etapa tumoral macroscópica, localization y tamaño tumoral, tipo según Bormann, nivel de infiltración, grado de diferenciación histológico, tipo histológico según Lauren, Ming y Nakamura, estado ganglionar linfático (N), estadio TNM y resultado de la resección realizada. Conclusiones: Las variables mencionadas deben ser cuidadosamente evaluadas al momento de decidir terapias en pacientes con CGA.

Factores morfológicos asociados al pronóstico de pacientes operados por cáncer gástrico incipiente / Pathological features associated with survival in early gastric cancer

Background: Early gastric cancer corresponds to those tumors that only involve mucosa and submuco-sa. It is associated with a high survival rate. Aim: To determine pathological factors associated with survival in early gastric cancer. Material and Methods: Analysis of pathological records of 106 patients, with a median age of 63 years (60 percent> males), subjected to a gastrectomy for early gastric cancer. Follow up was performed according to data in the clinical records and death certificates obtained at the Chilean National Death Registry. Results: Five years global survival of patients was 91 percento. Lymph node involvement was more common among tumors bigger than 35 mm, with a low degree of differentiation and among those tumors classified as diffuse according to Lauren. Survival was significantly lower for bigger tumors, those with of a low degree of differentiation, diffuse tumors according to Lauren and those with lymph node involvement. Conclusions: Early gastric cancer has a high five years survival. Bigger tumors, those with a low degree of differentiation and those with lymph node involvement are associated with lower survival rates.

Introducción: El cáncer gástrico incipiente (CGI) es aquel que compromete la mucosa o submucosa gástrica independientemente del compromiso ganglionar linfático, estimándose su prevalencia en Chile inferior al 20 por cientoo. El objetivo de este estudio es determinar prevalencia de CGI y asociación de variables biode-mográficas y morfológicas con la supervivencia (SV) de pacientes resecados por CGI. Material y Método: Estudio de cohorte retrospectiva. Se estudiaron variables biodemográficas y morfológicas de 106 pacientes resecados por CGI entre 1986-2007. Se aplicó estadística descriptiva y analítica; confección de curvas de SV, y finalmente se aplicaron modelos de regresión logística para realizar ajuste, calcular odds ratio y sus respectivos intervalos de confianza de 95 por ciento. Resultados: 15 por ciento correspondió a CGI. La mediana de edad fue 63 años y el 60 por ciento correspondió a género masculino con una SV global a 5 años de 91 por ciento. Se observaron diferencias estadísticas significativas entre tumores mucosos y submucosos en cuanto a la localización tumoral y compromiso linfonodal junto con presentarse el compromiso nodal más frecuentemente en tumores > 35mm poco diferenciados y difusos de Lauren. El análisis multivariado identificó como factores asociados a la SV: tamaño tumoral, grado de diferenciación histológica en su variedad poco diferenciado, tipo difuso de Lauren y compromiso ganglionar linfático. Conclusiones: Se verificó una prevalencia de CGI de 15 por ciento, los que resecados presentan SV de 91 por ciento a 5 años. El compromiso linfonodal es un factor asociado a la SV; y además, se relaciona con tamaño tumoral, tipo histológico según Lauren, grado de diferenciación histológico y nivel de infiltración.

Relación de la genotipificación de Helicobacter pylori con la forma e intensidad de la gastritis en población adulta portadora de patología gástrica benigna / Association between helicobacter pylori genotype and the severity of gastritis in infected adults

Background: The damaging capacity of Helicobacter pylori is variable and depends, in part, on its genetic polymorphism. Aim: To study H pylori genes vacA, cagA and iceA and the relationship of these genotypes with the features of acute damage in chronic gastritis. Material and methods: Gastric endoscopic biopsies were obtained in 75 adults for pathological study and genetic typification of H pylori by specific PCR. Results: In only 64 cases, complete information was available. In 53 of these, there was H pylori infection demonstrated by PCR. Twenty one percent had infection by two or more H pylori strains, vacA gene had genotypes s2/m2, s1/m1 and s1/m2 in 36, 25 and 8% of cases respectively, cagA gene was present in 49% of infected patients. iceA gene had genotypes iceA 1 ad iceA 2 in 15 and 60% of patients respectively. The presence of cagA or alleles s1/m1 and s1/m2 of vacA gene was directly correlated with polymorphonuclear infiltration and the severity of epithelial damage. The genotype s2/m2 of vacA gene was significantly associated with a milder or absent mucosal damage. No association was found between iceA alleles and the pathological features of gastritis. Conclusions: Alleles of vacA and cagA genes of H pilory are associated with the severity of gastric mucosal damage.

Alteraciones genéticas en gastritis crónica: Estudio de inestabilidad microsatelital y pérdida de la heterocigocidad / Genetic changes in chronic gastritis: study of microsatellite instability and loss of heterozygosity

Background: Multifocal chronic gastritis, associated to intestinal metaplasia, is considered a preneoplastic lesion, closely associated to intestinal type gastric cancer. Aim: To study the frequency of microsatellite instability (MSI) and loss of heterozygosity (LOH) in areas of chronic gastritis and intestinal metaplasia in gastric biopsies of patients without cancer. Material and methods: Gastric biopsy samples from 34 patients without cancer (22 with multifocal atrophic gastritis and 12 with diffuse antral gastritis), were studied. Glands from areas of chonic gastritis and intestinal metaplasia and lymphocytes, were collected using laser microdissection of paraffin embedded samples. The analysis of 15 mono and dinucleotide microsatellites was used to assess LOH and MSI. Results: LOH and MSI were found in some of the markers in 55% (12/22) and 59% (13/22) of cases with intestinal metaplasia, respectively. Only one of 12 areas with diffuse atrophic gastritis had MSI and a different area had LOH (p <0.05 or less, when compared with areas of multifocal atrophic gastritis). Three areas of normal epithelium in patients with multifocal atrophic gastritis, also had alterations. Most of these alterations were concordant with adjacent areas with intestinal metaplasia. Conclusions: LOH and MSI was found in areas of intestinal metaplasia in more than half of the studied cases and in few areas of atrophic gastritis without intestinal metaplasia. These findings suggest that genotypic alterations may precede phenotypic modifications and that intestinal metaplasia is a preneoplastic lesion (Rev Méd Chile 2003; 131: 1365-74).