Stomach cancer, medically known as gastric cancer, is a disease where cells in the stomach lining grow and divide abnormally, forming a tumor. It can affect any part of the stomach, which is the muscular organ located in the upper abdomen that aids in digestion. While it can occur across the entire lifespan, stomach cancer is predominantly recognized as a condition that affects older individuals. The risk increases considerably as a person ages, suggesting a long period is needed for cellular changes to accumulate.
When Stomach Cancer Incidence Peaks
Stomach cancer is overwhelmingly a disease of late adulthood, with the risk rising sharply in the sixth and seventh decades of life. The average age of diagnosis is approximately 68 years old. About 60% of all cases diagnosed each year occur in individuals aged 65 or older.
Incidence rates typically begin to rise noticeably around age 50 and continue to increase into the oldest age groups. This strong correlation with age is thought to be a result of the cumulative exposure to various risk factors over many years.
The time required for pre-cancerous changes, such as chronic inflammation or atrophy of the stomach lining, to fully progress into cancer is substantial. These slow, multi-step changes mean that younger individuals have had less time for the cancer-causing damage to occur. This pattern is consistent with many other types of cancer that also see their highest rates in older populations.
Understanding Early-Onset Gastric Cancer
While stomach cancer is most common in older adults, it can develop in younger people, a condition referred to as early-onset gastric cancer (EOGC). EOGC is generally defined as a diagnosis occurring in people aged 50 or younger. It represents a small fraction of all stomach cancer cases, though the proportion in this younger age group has been rising in some regions.
These early-onset cases often present with distinct characteristics compared to those in older patients. They are more likely to have a diffuse histology, meaning the cancer cells are scattered and less cohesive, making the disease potentially more aggressive. Younger patients are also more frequently diagnosed at an advanced stage, partly because symptoms may be overlooked or mistaken for more common, benign conditions.
Genetic factors are believed to play a greater role in EOGC, as younger individuals have had less time for environmental exposures to cause mutations. Conditions like Hereditary Diffuse Gastric Cancer (HDGC), caused by a mutation in the CDH1 gene, significantly increase the risk of developing stomach cancer at a young age. Other inherited syndromes, such as Lynch syndrome, also elevate the risk.
Contributing Factors Beyond Age
Age represents only one part of the risk profile for stomach cancer, with several other factors significantly increasing susceptibility. The largest environmental risk factor globally is chronic infection with the bacterium Helicobacter pylori (H. pylori). This bacterium causes long-term inflammation and ulcers, which can lead to pre-cancerous changes in the stomach lining.
Dietary habits also have a strong influence on risk. A diet high in salted, smoked, and pickled foods is associated with higher rates of stomach cancer. Conversely, a diet low in fresh fruits and vegetables offers less protection.
Lifestyle choices, such as smoking, roughly double a person’s risk compared to non-smokers. Additionally, chronic conditions like atrophic gastritis or pernicious anemia, which cause long-term inflammation and reduced stomach acid, can raise the risk. A family history of stomach cancer or certain inherited genetic syndromes also contributes to susceptibility.
Symptoms That Warrant Medical Consultation
Stomach cancer often does not cause noticeable symptoms in its earliest stages, which is one reason it is frequently diagnosed when the disease is advanced. When symptoms do appear, they can be vague and mimic those of less serious digestive issues like heartburn. It is crucial to consult a physician if any digestive symptoms persist or worsen over time.
Common warning signs include persistent indigestion or heartburn that does not respond to over-the-counter medication. Patients may also experience a feeling of being full after eating only a small amount of food, known as early satiety. Unexplained weight loss, persistent abdominal pain, and difficulty swallowing (dysphagia) are important indicators that warrant investigation.
Other signs can include chronic nausea, vomiting, or feeling unusually tired and weak due to anemia. Anemia occurs when there is slow, chronic blood loss from the tumor. While these symptoms can be caused by many conditions, a medical consultation is the only way to determine the underlying cause and ensure early diagnosis.