In particular, HER2 is overexpressed in 13–22% of patients with gastric cancer. Of note, HER2 overexpression in gastric neoplasia is heterogeneous and comprises a minority of tumor cells (less than 10% of gastric cancers overexpress HER2 in more than 5% of tumor cells). Hence, this heterogeneous expression should be taken into account for HER2 testing, particularly in small samples such as biopsies, requiring the evaluation of more than one bioptic sample. Radiation
Radiation therapy (also called radiotherapy) may be used to treat stomach cancer, often as an adjuvant to chemotherapy and/or surgery. Lymphoma
MALT lymphomas can often be fully treated by treating an underlying H. pylori infection. This results in remission in about 80% of cases. Prognosis
The prognosis of stomach cancer is generally poor, because the tumor has often metastasized by the time of discovery, and most people with the condition are elderly (median age is between 70 and 75 years) at presentation. The average life expectancy after being diagnosed is around 24 months, and the five-year survival rate for stomach cancer is less than 10%.Almost 300 genes are related to outcomes in stomach cancer, with both unfavorable genes where high expression is related to poor survival and favorable genes where high expression is associated with longer survival times. Examples of poor prognosis genes include ITGAV, DUSP1 and P2RX7. Epidemiology
Worldwide, stomach cancer is the fifth most-common cancer with 952,000 cases diagnosed in 2012. It is more common both in men and in developing countries.
Tentative evidence indicates that treating H. pylori decreases the future risk. If stomach cancer is treated early, it can be cured. Treatments may include some combination of surgery, chemotherapy, radiation therapy, and targeted therapy. For certain subtypes of gastric cancer, cancer immunotherapy is an option as well. If treated late, palliative care may be advised. Some types of lymphoma can be cured by eliminating H. pylori. Outcomes are often poor, with a less than 10% five-year survival rate in the Western world for advanced cases. This is largely because most people with the condition present with advanced disease. In the United States, five-year survival is 31.5%, while in South Korea it is over 65% and Japan over 70%, partly due to screening efforts.Globally, stomach cancer is the fifth-leading type of cancer and the third-leading cause of death from cancer, making up 7% of cases and 9% of deaths. In 2018, it newly occurred in 1.03 million people and caused 783,000 deaths. Before the 1930s, in much of the world, including most Western developed countries, it was the most common cause of death from cancer. Rates of death have been decreasing in many areas of the world since then. This is believed to be due to the eating of less salted and pickled foods as a result of the development of refrigeration as a method of storing food. Stomach cancer occurs most commonly in East Asia and Eastern Europe. It occurs twice as often in males as in females.