There are no specific treatment guidelines for OMS. Management may entail: Chemotherapy, surgery, and/or radiation: When a tumor is present, treatment such as surgery to remove the tumor, chemotherapy, or radiation may be necessary. These treatments aim to kill cancer cells while protecting normal tissue, so adverse effects are expected during therapy. Radiation therapy uses high-energy rays from a source such as x-rays, electrons, protons, or neutrons to destroy cancer cells. It can be used as single treatment or in combination with other therapies such as chemotherapy or targeted drugs. Radiation therapy plays an important role in many types of cancer care. Surgery is often recommended for people who have localized disease (that is, cancer that has not spread beyond its original site). For example, if your doctor finds only one small spot on an X-ray or scan of your body that contains cancer cells, then he or she may suggest surgery to remove this part of the liver. Surgery can also be useful when the cancer has spread but is still treatable, for example, if your oncologist finds out that some of your cancer cells are sensitive to certain medications or therapies. Finally, surgery may be required to remove cancerous tumors that cannot be removed any other way.