Resumen El cáncer gástrico ocupa el cuarto lugar en incidencia y el segundo en mortalidad entre todos los cánceres en todo el mundo. A pesar de la disminución de la incidencia en algunas regiones del mundo, el cáncer gástrico continúa siendo un reto clínico debido a que la mayoría de los casos se diagnostican en etapas avanzadas con mal pronóstico y las opciones de tratamiento limitadas. El desarrollo de cáncer gástrico es un proceso complejo y multifactorial que implica un número de factores etiológicos y múltiples alteraciones genéticas y epigenéticas. Entre los factores predisponentes están: infección por Helicobacter pylori, alto consumo de sal, tabaquismo, y en un pequeño porcentaje de los pacientes, un componente genético familiar. Más del 95% de los casos de cáncer de estómago son adenocarcinomas, que se clasifican en dos principales tipos histológicos: intestinal y difuso. Adenocarcinoma de tipo intestinal es precedida por una secuencia de lesiones gástricas conocidas como cascada de Correa y es el tipo histológico asociado con la disminución global de las tasas de cáncer gástrico. Los Adenocarcinomas de tipo difuso tienen un comportamiento más agresivo y peor pronóstico que aquellos del tipo intestinal. De acuerdo con la localización anatómica, los adenocarcinomas se clasifican como proximal (originario en el cardias) y distal (que se origina en el cuerpo y antro). Esta clasificación parece reconocer dos entidades clínicas diferentes. La resección quirúrgica del tumor en una etapa temprana es el método de tratamiento eficaz. Por lo tanto, la identificación y vigilancia de los pacientes de alto riesgo pueden desempeñar un papel importante en las tasas de supervivencia. La terapia anti-Helicobacter pylori ha demostrado ser una medida eficaz en la prevención del cáncer gástrico.

Abstract Gastric cancer ranks fourth in incidence and second in mortality among all cancers worldwide. Despite the decrease in incidence in some regions of the world, gastric cancer continues to present a major clinical challenge due to most cases being diagnosed in advanced stages with poor prognosis and limited treatment options. The development of gastric cancer is a complex and multifactorial process involving a number of etiological factors and multiple genetic and epigenetic alterations. Among the predisposing factors are: Helicobacter pylori infection, high salt intake, smoking, and in a small percentage of patients, a familial genetic component. More than 95% of stomach cancer cases are adenocarcinomas, which are classified into two major histologic types: intestinal and diffuse. Intestinal type adenocarcinoma is preceded by a sequence of gastric lesions known as Correa´s cascade and is the histologic type associated with the global decrease in gastric cancer rates. Diffuse type adenocarcinomas have a more aggressive behavior and worse prognosis than those of the intestinal type. According to the anatomical location, adenocarcinomas are classified as proximal (originating in the cardia) and distal (originating in the body and antrum). This classification seems to recognize two different clinical entities. Surgical resection of the tumor at an early stage is the only effective treatment method. Therefore, the identification and surveillance of patients at risk may play a significant role in survival rates. Anti-Helicobacter pylori therapy has been shown to be an effective measure in the prevention of gastric cancer.

ABSTRACT Purpose :The Population-based Cancer Registry of Cali aims to report all new cases in permanent residents within the limits of the city of Cali. Time trends of cancer incidence and mortality are described. The registry has been in continuous operation for 50 years. Methods: Cancer cases reports are obtained actively by visiting all sources of information: hospitals, pathology departments, hematology laboratories, radiotherapy centers, government offices where death certificates are processed and physician's offices. It is estimated that the reporting is at least 95% complete. Results: Drastic decreases are documented in rates for tumors causally related to infectious agents, especially cancers of the uterine cervix and the stomach. Gradual increases are documented in rates of tumors linked to affluence and the metabolic syndrome, especially cancers of the colon and the female breast. An unexpected increase in the incidence of papillary carcinoma of the thyroid gland in women is reported. Tobacco-related cancers, especially cancer of the lung, showed marked increase in incidence rates around 1970, apparently the beginning of an epidemic similar to the one reported in Western societies. But the increase in incidence stopped around 1980, resulting from a strong anti-smoking campaign launched in Colombia in the 1970s. Conclusions: The findings have influenced prevention strategies implemented by public health authorities, specially the establishment of a city-wide program to prevent cervix cancer via widespread use of vaginal cytology and anti-smoking campaigns. Also, new population-based cancer registries have been established in other Colombian cities as well as in Ecuador.

El cáncer gástrico representa la primera causa de mortalidad por cáncer en Colombia. La mayor parte de los casos se diagnostican cuando las celulas malignas han invadido la capa muscular, lo cual conlleva una tasa de sobrevida a los cinco años inferior a 20%. El cáncer invasivo esta precedido por un prolongado proceso precanceroso que empieza en la niñez como resultado de la infeccion con Helicobacter pylori. Las etapas siguientes incluyen atrofia multifocal de las glandulas, metaplasia intestinal y displasia. En pacientes con diagnostico de metaplasia intestinal se debe evaluar la extensión de la lesión y el grado de diferenciación para determinar la conducta a seguir. Aunque las tasas de incidencia de cáncer gástrico han estado disminuyendo en las últimas décadas, recientemente se ha detectado un aumento en personas jóvenes, de causa desconocida.

Gastric cancer is the first cause of cancer mortality in Colombia. The majority of cases are diagnosed when the malignant cells have already invaded the muscularis, which translates into a five year survival rate of less than 20%. Invasive cancer is preceded by a prolonged precancerous process resulting from Helicobacter pylori infection that starts in childhood. Subsequent stages include multifocal atrophy of the glands, intestinal metaplasia, and dysplasia. In patients with the diagnosis of intestinal metaplasia one should evaluate the extent of the lesion as well as the degree of differentiation in order to determine adequate management. Although gastric cancer incidence rates have been diminishing in the last decades, just recently an increment of unknown cause has been detected in young persons.

Introducción: El cáncer gástrico es la malignidad más común en América del Sur y Asia oriental. En Colombia, aparte del grave problema de mortalidad, una limitante es la escasez de datos de prevalencia de lesiones tempranas y premalignas. Objetivos y métodos: Evaluar la utilidad de la cromoendoscopia sistemática en la prevalencia de de cáncer gástrico temprano y lesión gástrica pre-maligna. Un total de 950 sujetos fueron convocados. 800 sujetos cumplieron los criterios de inclusión y finalmente 650 fueron analizados. Resultados: Ninguno de los participantes presentó mucosa gástrica normal. Gastritis antral crónica leve se encontró en 21,8% (142/650) mientras que gastritis antral crónica moderada o severa se encontró en el 77,4% (508/650). Atrofia y metaplasia fue encontrada en 14,5% (94/650) y 15,5% (101/650) respectivamente. Infección por H. Pylori en 7,3%, 79,3% 75,5% 57,4% y 0% de los sujetos con gastritis antral leve, gastritis moderada o severa, atrofia, metaplasia y displasia respectivamente. Lesión gástrica premaligna en 30% (195/650). Dos participantes fueron diagnosticados con cáncer gástrico temprano y tratados curativamente con disección endoscópica de la submucosa. Conclusión: Utilizando cromoendoscopia sistemática esta serie ha demostrado que uno de 325 voluntarios sanos tiene cáncer gástrico temprano, y 1 de cada 33 tiene lesión gástrica premaligna explicando así la alta prevalencia de cáncer gástrico avanzado en la región. En voluntarios sanos de Colombia el cáncer gástrico temprano es diagnosticable y curable.

Indroduction: Gastric cancer is the most common maligancy in South America and East Asia. In addition to the high mortality, in Colombia a great disvantage is the lack of data regarding premalignant lesions and early cancer. Aim: To evaluate the usefulness of systematic chromoendoscopy in the prevalence of early cancer and gastric premalignant lesions. A total of 950 were invited to participate, 800 fulfilled the inclusion criteria and finally 650 were analyzed. Results: None of participants had normal gastric mucosa. Mild antrum gastritis was found in 21.8% (142/650), meanwhile moderate or severe antrum gastritis in 77.4% (508/650). Atrophy and metaplasia was found in 14.5% (94/650) and 15.5% (101/650) respectively. H Pilory infection was found in 7.3%, 79.3% 75.5% 57.4% y 0% of subjects with mild, moderate and severe, atrophy, metaplasia and dysplasia respectively. Gastric premalignant lesion was found in 30% (195/650). Two subjects were diagnosed as early gastric cancer and treated by endoscopic submucosal dissection (ESD) with curability as final result. Conclusions: By systematic chromoendoscopy this series has demonstrated that 1/325 healthy volunteers had early gastric cancer and that 1/33 had a premalignant lesion explaining in part the high prevalence of gastric cancer in the region. Bases on this series, gastric cancer is diagnosable and curable among healthy volunteers in Colombia.

Introducción El mapeo de las diferentes regiones del estómago y el número de fragmentos de mucosa gástrica disponibles para evaluación histopatológica son fuentes importantes de variación en el momento de clasificar y hacer la gradación de la gastritis crónica. Objetivos: Estimar la sensibilidad del número de fragmentos de mucosa gástrica necesarios para establecer los diagnósticos de gastritis atrófica con metaplasia intestinal (MI), displasia y estado de infección por Helicobacter pylori. Además evaluar la variabilidad intra-observador en la clasificación de estas lesiones precursoras del cáncer gástrico. Materiales y métodos: En una cohorte de 6 años de seguimiento se evaluaron 1, 958 procedimientos de endoscopia realizados por dos gastroenterólogos. En cada procedimiento y de cada participante se obtuvieron 5 biopsias de mucosa gástrica que representaban antro, incisura angularis y cuerpo. Un único patólogo hizo la interpretación histológica de las 5 biopsias y proporcionó un diagnóstico definitivo global que se utilizó como patrón de referencia. Cada fragmento de mucosa gástrica examinado condujo a un diagnóstico individual para cada biopsia que se comparó con el patrón de referencia. La variabilidad intra-observador se evaluó en 127 personas que corresponden a una muestra aleatoria de 20% del total de endoscopias hechas a los 72 meses de seguimiento. Resultados: La sensibilidad del diagnóstico de MI y displasia gástrica aumentó de manera significativa con el número de fragmentos de mucosa gástrica evaluados El sitio anatómico de mayor sensibilidad para el diagnóstico de MI y displasia fue la incisura angularis. Para descubrir H. pylori se logró alta sensibilidad con el estudio de un solo fragmento de mucosa gástrica (95.9%) y fue independiente del sitio de obtención de la biopsia. El acuerdo intra-observador para el diagnóstico de gastritis crónica fue 86.1% con valor kappa de 0.79 IC 95% (0.76-0.85). Las biopsias fijadas en alcohol fueron inadecuadas para demostrar H. pylori e interpretar los cambios de displasia. Conclusión: El número de fragmentos de mucosa gástrica evaluados, el método de fijación y la región del estómago donde se obtienen las biopsias son factores muy importantes para lograr una correcta clasificación de la gastritis crónica atrófica multifocal.

Introduction Multiple sampling from different sites of the stomach as well as the number of fragments of gastric mucosa available for histopathologic evaluation are important sources of variation when classifying and grading chronic gastritis. Objective To estimate the sensitivity of the number of fragments of gastric mucosa necessary to establish the diagnosis of atrophic gastritis with intestinal metaplasia, gastric dysplasia and H. pylori infection. In addition, this study will attempt to assess the intra-observer variability in the classification of these premalignant gastric lesions. Methods: This is a 6 year-cohort study, wherein 1958 gastric endoscopic procedures performed by two gastroenterologists were reviewed. Five gastric biopsy samples were obtained from the antrum, body and lesser curvature during each procedure. One pathologist was in charge of reviewing the five histopathology samples for each subject and providing a definitive diagnosis which was used as the gold standard. Each gastric mucosa sample reviewed led to an individual diagnosis for that sample which was compared with the gold standard. Intra-observer variability was assessed in 127 individuals who correspond to a random sample of 20% of the total endoscopic procedures performed during the 72 month-follow-up. Results: The sensitivity of the diagnosis of intestinal metaplasia (IM) and gastric dysplasia increased proportionally with the number of gastric mucosa samples reviewed. The lesser curvature of the stomach had the highest sensitivity for the diagnosis of IM and dysplasia, among all the stomach regions studied. Just one sample of gastric mucosa attained a sensitivity of 95.9% for the detection of H. pylori infection. The intra-observer agreement for the diagnosis of multifocal atrophic gastritis was 86.1% and the kappa value was 0.79 (95% CI 0.76-0.85). Alcohol-fixed biopsy specimens were inadequate to diagnose H. pylori infection and to assess dysplasia. Conclusion The number of mucosa gastric fragments reviewed, the fixation method used, and the biopsy site are all important factors in order to ensure a correct classification of chronic gastritis.

Gastric cancer is the leading cause of cancer deaths in the general population in Chile, with mortality rates as high as 33.7 per 105 in males in the IX region. A chain of genetic and morphological events precedes the intestinal type of gastric carcinoma. One of them is the called multifocal atrophic gastritis often associated with intestinal metaplasia. Aim: To study the frequency of microsatellite instability (MSI) and loss of heterocigozity (LOH) in neoplastic and preneoplastic lesions of gastric carcinoma, especially intestinal metaplasia. Material and methods: Ninety four gastric cancer biopsies were studied using laser capture microdissection, to obtain well defined cell populations from paraffin-embedded tissues: lymphocytes (control DNA), intestinal metaplasia and gastric cancer areas. Primer flanking microsatellite 15 highly polymorphic regions were used to study MSI and LOH. Radioactive PCR products were electrophoresed and exposed for autoradiography. Results: LOH was observed in 83% of gastric carcinomas and in 54% areas containing intestinal metaplasia. The most commonly altered regions were the CA repeat associated with the p53 gene and the 3p21 region. High grade MSI was observed in 11.7% of gastric cancer preparations and 17% of intestinal metaplasia associated to cancer with MSI-H phenotype. Conclusions: MSI and LOH were frequently observed in intestinal metaplasia glands in patients with gastric carcinoma. The frequency of MSI-H phenotype in gastric patients was slightly lower than the one described in sporadic colorectal cancer not associated to HNPCC. The high incidence of genetic lesions in intestinal metaplasia area, support the idea that intestinal metaplasia is a genetically highly unstable cell population (Rev Méd Chile 2003; 131: 1227-36).

A associação do câncer de esôfago com os hábitos de fumar e beber, escolaridade e fatores nutricionais foi verificada em um estudo epidemiológico tipo caso-controle, conduzido no Município de São Paulo (Brasil). Oitenta e cinco casos foram comparados com 292 controles hospitalares, com diferentes diagnósticos, inclusive outros tipos de câncer. Estimativas brutas, por ponto e por intervalo, dos odds ratios, foram obtidas para as variáveis de estudo. Com base nos resultados da análise bruta, foram selecionadas oito variáveis para a utilização de análise logística multivariada. O modelo final sugere que tanto o hábito de beber [odds ratio = 3,68; intervalo com 95% de confiança (1,74 - 7,78)], como o de fumar [odds ratio = 4,86; intervalo com.95% de confiança (1,95 - 12,13)] e o consumo freqüente de pimenta [odds ratio = 2,48; intervalo com 95% de confiança (1,46 - 4,23)] são fatores de risco importantes para a doença. Obteve-se odds ratio 3,43 (1,31 - 8,97) para o hábito de fumar cigarro comum e odds ratio 4,18 (1,38 - 12,66) para cigarro de palha.

The association between esophageal cancer and smoking and drinking habits, instruction and nutritional factors was examined by means of the utilization of data of a case-control study wich was undertaken in the city of S. Paulo (Brazil). Eighty five cases were compared with two hundred and ninety two hospital controls, with different diseases, including other kinds of cancer. The crude estimations of the odds ratios were calculated for all the variables. Logistic regression was used in the next steps of the analysis. The drinking habit [odds ratio = 3.68; 95% confidence interval (1.74 - 7.78)], the smoking habit [odds ratio = 4.86; 95% confidence interval (1.95 - 12.13)] and the frequent eating of hot pepper [odds ratio = 2.48; 95% confidence interval (1.46 - 4.23)] are important risk factors for the disease. The estimate of odds ratio for smoking ordinary cigarette was of 3.43 (1.31 - 8.97) and for smoking of com straw hand-rolled cigarette was of 4.18 (1.38- 12.66).

A associação do câncer de esôfago com os hábitos de fumar e beber, escolaridade e fatores nutricionais foi verificada em um estudo epidemiológico tipo caso-controle, conduzido no Município de São Paulo (Brasil). Oitenta e cinco casos foram comparados com 292 controles hospitalares, com diferentes diagnósticos, inclusive outros tipos de câncer. Estimativas brutas, por ponto e por intervalo, dos odds ratios, foram obtidas para as variáveis de estudo. Com base nos resultados da análise bruta, foram selecionadas oito variáveis para a utilização de análise logística multivariada. O modelo final sugere que tanto o hábito de beber [odds ratio = 3,68; intervalo com 95% de confiança (1,74 - 7,78)], como o de fumar [odds ratio = 4,86; intervalo com.95% de confiança (1,95 - 12,13)] e o consumo freqüente de pimenta [odds ratio = 2,48; intervalo com 95% de confiança (1,46 - 4,23)] são fatores de risco importantes para a doença. Obteve-se odds ratio 3,43 (1,31 - 8,97) para o hábito de fumar cigarro comum e odds ratio 4,18 (1,38 - 12,66) para cigarro de palha.

The association between esophageal cancer and smoking and drinking habits, instruction and nutritional factors was examined by means of the utilization of data of a case-control study wich was undertaken in the city of S. Paulo (Brazil). Eighty five cases were compared with two hundred and ninety two hospital controls, with different diseases, including other kinds of cancer. The crude estimations of the odds ratios were calculated for all the variables. Logistic regression was used in the next steps of the analysis. The drinking habit [odds ratio = 3.68; 95% confidence interval (1.74 - 7.78)], the smoking habit [odds ratio = 4.86; 95% confidence interval (1.95 - 12.13)] and the frequent eating of hot pepper [odds ratio = 2.48; 95% confidence interval (1.46 - 4.23)] are important risk factors for the disease. The estimate of odds ratio for smoking ordinary cigarette was of 3.43 (1.31 - 8.97) and for smoking of com straw hand-rolled cigarette was of 4.18 (1.38- 12.66).

São examinados aspectos da incidência de câncer do esôfago para residentes no município de São Paulo, (Brasil), no ano de 1975. Dados coletados pelo Registro de Câncer mostram um coeficiente de 6,4 e 1,3 por cem mil homens e mulheres, respectivamente; quando padronizados pela "população mundial" os coeficientes são 9,2 e 2,0 por cem mil. As taxas do sexo masculino mostram que São Paulo está a um nível de risco maior do que outras três cidades brasileiras, com dados conhecidos, Fortaleza, Recife e Rio de Janeiro; no sexo feminino não há evidências de diferenças, a não ser possivelmente em relação a Fortaleza. As curvas de incidência específica segundo idade e sexo concordam com o padrão descrito por Higginson e Muir; valores para a inclinação do 1nI (incidência específica por idade) nas idades 35 a 75 foram 5,7 para o sexo masculino e 4,4 para o feminino, ajustando-se uma linha reta. Os nativos de São Paulo apresentam uma menor incidência do que os nascidos fora da cidade; para as duas categorias de imigrantes brasileiros residentes de São Paulo, as incidências para homens são consistentemente altas. As razões masculino-feminino de incidência apresentam regularidade nos grupos brasileiros; entre os estrangeiros as razões são maiores.

Aspects of the incidente of cancer of the oesophagus in residents of the city of S. Paulo, Brazil, for 1975, are examined. Data collected by the Cancer Registry yield a rate of 6.4/100,000 and 1.3/100,000 for males and females, respectively; when adjusted to the «world-population» the rates are 9.2/100,000 and 2.0/100,000. Male rates put S. Paulo at higher risk than three other Brazilian cities with known data, namely Fortaleza, Recife and Rio de Janeiro; for females there is no strong indication of differences, except in the case of Fortaleza. The specific age-sex incidence curves conform well to the pattern described by Higginson and Muir; values for the curves of 1nI (age-specific rate) at ages 35 through 75 were 5.7 for males and 4.4 for females, when adjusting a straight line. S. Paulo city natives present a lower incidence than people born elsewhere; for the two categories of migrants within Brazil, living in S. Paulo, the age-specific incidence rates for males are consistently very high. Male-female ratio patterns are fairly regular among the three Brazilian groups; the foreign-born present higher ratios.

São examinados aspectos da incidência de câncer do esôfago para residentes no município de São Paulo, (Brasil), no ano de 1975. Dados coletados pelo Registro de Câncer mostram um coeficiente de 6,4 e 1,3 por cem mil homens e mulheres, respectivamente; quando padronizados pela "população mundial" os coeficientes são 9,2 e 2,0 por cem mil. As taxas do sexo masculino mostram que São Paulo está a um nível de risco maior do que outras três cidades brasileiras, com dados conhecidos, Fortaleza, Recife e Rio de Janeiro; no sexo feminino não há evidências de diferenças, a não ser possivelmente em relação a Fortaleza. As curvas de incidência específica segundo idade e sexo concordam com o padrão descrito por Higginson e Muir; valores para a inclinação do 1nI (incidência específica por idade) nas idades 35 a 75 foram 5,7 para o sexo masculino e 4,4 para o feminino, ajustando-se uma linha reta. Os nativos de São Paulo apresentam uma menor incidência do que os nascidos fora da cidade; para as duas categorias de imigrantes brasileiros residentes de São Paulo, as incidências para homens são consistentemente altas. As razões masculino-feminino de incidência apresentam regularidade nos grupos brasileiros; entre os estrangeiros as razões são maiores.

Aspects of the incidente of cancer of the oesophagus in residents of the city of S. Paulo, Brazil, for 1975, are examined. Data collected by the Cancer Registry yield a rate of 6.4/100,000 and 1.3/100,000 for males and females, respectively; when adjusted to the «world-population» the rates are 9.2/100,000 and 2.0/100,000. Male rates put S. Paulo at higher risk than three other Brazilian cities with known data, namely Fortaleza, Recife and Rio de Janeiro; for females there is no strong indication of differences, except in the case of Fortaleza. The specific age-sex incidence curves conform well to the pattern described by Higginson and Muir; values for the curves of 1nI (age-specific rate) at ages 35 through 75 were 5.7 for males and 4.4 for females, when adjusting a straight line. S. Paulo city natives present a lower incidence than people born elsewhere; for the two categories of migrants within Brazil, living in S. Paulo, the age-specific incidence rates for males are consistently very high. Male-female ratio patterns are fairly regular among the three Brazilian groups; the foreign-born present higher ratios.