Radiotherapy is also known as radiation therapy. It is used in the treatment of several kinds of cancer. It attacks both cancerous cells and normal cells, which is why it has so many side effects.
One article (1) looked at radiotherapy and its possible side effects. It noted that there are fewer side effects when given orally as there have been advancements in how radiotherapy is given. The major side effects of radiotherapy include dry or itchy skin, blistering of the skin, tiredness, developing a second cancer later in life, dry mouth, difficulty swallowing, and mouth sores (if the radiation is given to the head or neck area), shortness of breath, shoulder stiffness, breast of nipple soreness, and difficulty swallowing (if the chemotherapy is given to the chest area), and diarrhea along with nausea and vomiting (if the radiation is given to the abdomen).
Fortunately, many of these side effects dissipate after the radiotherapy has been discontinued. Hair loss is not a side effect unless the radiation is directed toward the scalp area.
Source: 1.Side Effects of Radiation Therapy. http://www.cancer.net/navigating-cancer-care/how-cancer-treated/radiation-therapy/side-effects-radiation-therapy. Accessed 8/1/16.
Dr. Adem Gunes