Good nutrition before and after surgery, which is often the first step in the treatment process, is particularly critical for people with later-stage cancer who may already be experiencing wasting or malnutrition, which increases risk for infection or other treatment complications. "Surgery puts a great deal of stress on the body and recovery can increase the amount of calories and protein the body requires," Grotto says. The amount of calories and protein needed varies from person to person and is based on factors other than wound healing, such as age, weight and the degree to which someone is physically active.
Nutritional challenges due to surgery itself depend upon where in the body the surgery is taking place. For example, surgery for cancer of the head and neck may make chewing and swallowing difficult, which may require a diet with foods of a soft consistency, Grotto says. Cancers of the stomach or intestines or colon may involve the removal of part of the digestive system, which can cause diarrhea or constipation.
As with surgery, the nutritional problems radiation therapy causes depend on what part of the body is being targeted. The beam of radiation that is focused on the area containing the cancer cells may also damage any healthy cells in its path. A woman getting upper chest radiation for breast cancer, for example, might have burning in the esophagus, while radiation to the abdomen can cause stomach irritation, nausea and lactose intolerance. And radiation to the colon, rectum, prostate, ovaries, uterus, cervix and bladder can cause diarrhea.
