Not everyone who gets cancer will lose their hair. Hair loss is related to the treatment of cancer rather than the cancer itself. When cancer is treated with chemotherapy (drug therapy) hair loss can happen. Not all chemotherapy drugs cause hair loss but many can. Sometimes all the hair is lost and sometimes it just gets thinner. Hair can be lost from all parts of the body with chemotherapy. Hair loss can also occur if a person has radiotherapy to that part of the body e.g. hair might be lost on the head if radiotherapy is given to the head or on the chest if radiotherapy is given in the chest area.