Weight loss will depend on the area treated. For instance, patients undergoing breast irradiation, should not lose weight. Weight loss during radiotherapy may be observed in some patients, particularly because of:
1 – decreased food intake due to loss of appetite or difficulties in swallowing caused by radiation therapy acute side effects in the oral cavity, pharynx or esophagus when these areas are irradiated.
2 –increased digestive losses, for example due to diarrhea secondary to acute intestinal side effects following abdominal-pelvic irradiation.