The staging of stomach cancer is complicated, but is generally based on how far the tumor has advanced through the gastric wall and how many lymph nodes have been affected. Treatment for the disease is largely based upon its progression as indicated by the staging process. If the cancer is localized, a partial gastrectomy, which involves the surgical removal of portions of the stomach, is generally the treatment of choice and may result in a permanent cure. More advanced cases of stomach cancer may necessitate the complete removal of the stomach as well as many of the nearby lymph nodes. Severe dietary changes generally are required of those who undergo stomach surgery and intravenous administration of vitamins may be necessary. Patients that are not suited for surgery typically are administered chemotherapy, radiotherapy, or a combination of the two.