The customary treatment of metastasized stomach cancer is chemotherapy. Chemotherapy is also used as adjuvant therapy after the tumor has been excised in the earlier stage and has been proven to be effective. Unfortunately, only in about one third of patients is the tumor discovered at a stage when such therapy is still possible. Stomach cancer is quite resistant to radiation therapy and the amount of radiation that is effective against the tumor damages adjacent structures, such as mucosa in the digestive system. In recent years, biological therapy has also been introduced (such as drugs that block the HER2 receptor) for treating advanced stages of stomach cancer, but this therapy is only suitable for tumors with over-expression of the HER2 receptor (prevalent in about 15-20% of patients).
By targeting treatment to fight other biological mechanisms that are active in the tumor, oncologists can use a wider range of biological drugs and immunotherapy on a larger number of patients.
Biological therapy: biological drugs work on various receptors in cancerous tissue with the aim of preventing the cancer from proliferating or of affecting genome mutations that activate cell-division mechanisms. In this way, these targeted drugs succeed in destroying the tumor.
Immunotherapy: drugs that use the immune system to fight the tumor, when the tumor is paralyzing the immune system. One of the known mechanisms uses the immune system in a focused way with drugs that inhibit PD1.
Personalized therapy: in instances when tumors are not responding to the customary chemotherapy for metastasized stomach cancer, advanced tests may be used in order to try to pinpoint targets for various treatments. The most suitable therapy may then be decided according to the biological characteristics of the tumor tissue, whether chemotherapy, biological therapy, immunotherapy or even hormone therapy, which had not previously been considered effective.
Stomach cancer and genetics: in about 1-3% of stomach cancer patients, there is a possibility that the disease was hereditary. For example, inherited carriers of mutations in the CDH1 gene and an inherited syndrome of colon cancer and hereditary nonpolyposis colorectal cancer (HNPCC), which is also called “Lynch Syndrome,” were found in families of patients with high incidence of stomach cancer.