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A biennial endoscopy could detect gastric cancer in early stages and reduce mortality rate

A team of researchers led by PhD. Ismael Riquelme from Universidad Autónoma de Chile located in the city of Temuco, Chile and Dr. Enrique Bellolio from Universidad de la Frontera conducted a study were the results suggest that biennial endoscopic surveillance in patients older than 50 years with gastric symptomatology and patients presenting the Operative Link on Gastritis Assessment (OLGA) scores > 2 could save lives.

  
María Paz Ilabaca
By María Paz Ilabaca
Periodista Científica

26, August 2019

endoscopia

In Chile, gastric tumors are the primary cause of cancer-related deaths in the entire population, affecting twice as many men as women, particularly in certain areas of Chile, namely the regions of Maule, Bio-Bio and La Araucanía which have the highest mortality rates related to gastric cancer.

OLGA is a stratification scale of gastric lesions designed by an international group of pathologists which links the presence, location, extent and histological features (cells and tissue characteristics to microscopic level) of premalignant gastric lesions, classifying them according to their probability to develop gastric cancer, in a progressively increasing scale of risk or "stages" ranging from 0 to IV. Using the OLGA tool, the research team analyzed 485 patients (306 women and 179 men) between 13 and 93 years old from Temuco, who underwent a digestive endoscopy with gastric biopsy between the years 2011 and 2013.

Endoscopic biopsy samples were examined under a microscope to evaluate histopathological features. Patients harbouring stages I and II, tested positive for both gastric atrophy and metaplasia, but showed low frequency of cancer, while those in stages III and IV had more advanced lesions; these results allowed the researchers to establishing that, as the age of patients increased, the frequency of people with higher OLGA scores, increased too.

The research also evaluated the presence of Helicobacter pylori, which is directly related to chronic gastritis and it is considered as a previous step towards the development of gastric cancer. This bacterium infects the stomachs of approximately half of the world's human population and has a particularly high prevalence in Latin America and much of Asia. In Chile, the Helicobacter pylori prevalence varies between 65-79%, depending on the socioeconomic, educational and health conditions of the population studied. The researchers found that, from a total of 485 patients, 30.3% were infected by Helicobacter pylori. In addition, a higher frequency of H. pylori infection was observed in young patients between 13 and 44 years old, which was significantly higher than the one found in patients between 45 and 56 years of age. Of the patients with gastric cancer only 14.3% had Helicobacter pylori infection and out of the ones infected all of them were older than 56 years old. Based on this finding, researchers highlight that, although Helicobacter pylori initiates the carcinogenic process, it does not necessarily remain throughout the process until the cancer develops.

Additional analysis showed that one third of patients Helicobacter pylori infected already had gastric atrophy. The same was found when evaluating the association between Helicobacter pylori infection and metaplasia. Helicobacter pylori–associated atrophic gastritis is frequently asymptomatic, but individuals with this disease are at an increased risk of developing gastric carcinoma. Therefore, the authors recommend performing an endoscopic surveillance every two years (biennial) in those patients, symptomatic or not, that show an initial OLGA score > 2, regardless of their age. On the other hand, if the health system is over-demanded, it is recommended to study patients over 50 years of age and continue to follow up biennially to those with an OLGA> 2. Implementing this health policy would be helpful to diagnose stomach cancer in its early stages and reduce the mortality rate in the coming two decades in Chile. The authors concluded that the OLGA staging system is a very useful tool to predict the behavior of gastric cancer precursor lesions, which is the most lethal cancer affecting men in Chile. Specially because patients with these lesions may be asymptomatic or had very nonspecific symptoms, therefore gastric cancer and its precursor lesions early diagnosis is often challenging.

In deep…
Gastric atrophy and intestinal metaplasia


Gastric atrophy is an epithelial lesion characterized by a decrease in gastric glands and therefore of the cells that normally compose it. An example are the oxyntic cells, which produces hydrochloric acid and the Intrinsic Factor (a protein necessary for the absorption of vitamin B12) both are part of the components that together are called the gastric juices. On the other hand, intestinal metaplasia is a condition in which normal cells, that line the stomach, are replaced by atypical gastric cells, whose morphology is very similar to those cells that line the intestine, causing a decrease in gastric function and secretion. Hence, both gastric atrophy - also known as atrophic gastritis - and intestinal metaplasia are considered stomachs precancerous lesions.

María Paz Ilabaca
By María Paz Ilabaca
Periodista Científica

26, August 2019