November is Stomach/Gastric
Cancer Awareness month. The stomach is responsible for receiving and digesting
bolus (chewed foods)–essentially preparing the foods for nutrient absorption in
the small intestines. Cancer arises when cells in the stomach lining accumulate
a buildup of mutations, leading to loss of cell cycle regulations. Risk factors
of gastric cancer include age 55 years and older, male, smoking, genetics, and
diet choices. It is also highly correlated with previous bacterial infection
from Helicobacter pylori, which will be discussed in this article.
What is H. pylori?
H. pylori is a spiral rod shaped bacterium that thrive in microaerophillic
conditions (requiring low oxygen concentration, much like your stomach
environment). It is also equipped with tail-like “flagella” used for navigation
in the stomach. It is thought that the bugs propel themselves quickly away from
the acidic conditions of the stomach contents towards the stomach mucosal
lining, which is less acidic. Once H. pylori establish themselves in the mucosal lining, they cause
inflammation and damage, and eventually acid will breach to deeper stomach
lining layers, causing ulcers and gastric pains.
H. pylori-associated
peptic ulcers
Traditionally, stomach ulcers
and inflammation were associated with stress, spicy foods, and smoking.
However, physician pathologist team Dr. Barry Marshall and Dr. Robin Warren
frequently observed helical shaped bacteria in the stomach slides of patients suffering
from gastric ulcers, and were convinced that the bacteria played a part in
causing the stomach ulcers. In the summer of 1984, Dr. Marshall became a guinea
pig doctor and infected himself by ingesting broth filled with the bacteria.
Subsequently, he cured himself with antibiotics–thus establishing the link
between stomach ulcers and H. pylori. Their discovery led them to the ultimate accolade: the 2005
Nobel Prize in Medicine.
H. pylori, or the Corkscrew Bug, is found in the environment, but is closely associated
with where hygiene is poor. Therefore, a person may be infected via
contaminated water, food, and more. Direct transmission from an infected person
to another is also very likely. In developing countries, infection mostly
occurs during childhood and affects more than 80% of the population. In
industrialized areas, the percentage is below 40%.
People colonized with H. pylori have a 10-20% chance of developing stomach ulcers, and a 1-2% risk
of developing gastric cancer. The factors involved include bacterial-host
interaction and environmental factors.
Symptoms
Sufferers from stomach ulcers
likely have dull aching stomach pains, especially in between meals when the
stomach is empty and acid can directly irritate the ulcers. Symptoms may be alleviated
by eating, especially non-acidic foods. Other signs include bloating or nausea.
If ulcer bleeding occurs, one may vomit blood or coffee-ground like substance
or have bloody stools, sharp pains in the stomach, fatigue, and more.
Overtime if left untreated, H. pylori infection may lead to gastric cancer. Symptoms include general
gastric distress (heartburn, stomach pains, bloating, small appetite,
vomiting).
Treatments
Because of the widespread
nature of H. pylori and that it does not always cause disease, doctors will only
screen for and treat H. pylori colonization if symptoms are present. Treatment usually include multiple antibiotic classes combined with stomach
acid reducers or bismuth subsalicylate. It is important to adhere to the full
course of treatment as failure to do so will harbor antibiotic resistance in H. pylori, making future treatments more
difficult. Avoid NSAIDs pain killers, spicy foods, smoking, and alcohol, as
these will usually worsen your symptoms.
Prevention is also effective in
reducing H. pylori transmission, such as being mindful about handwashing and avoiding
contaminated sources.
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