Radiation therapy uses high-energy radiation to shrink tumors and kill cancer cells.

The radiation may be delivered by a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy), also called( brachytherapy).

Radiation therapy can cause both early (acute) and late (chronic) side effects. Acute side effects occur during treatment, and chronic side effects occur months or even years after treatment ends . The side effects that develop depend on the area of the body being treated, the dose given per day, the total dose given, the patient’s general medical condition, and other treatments given at the same time.

Acute radiation side effects are caused by damage to rapidly dividing normal cells in the area being treated. These effects include skin irritation or damage at regions exposed to the radiation beams. Examples include damage to the salivary glands or hair loss when the head or neck area is treated, or urinary problems when the lower abdomen is treated.

Fatigue is a common side effect of radiation therapy regardless of which part of the body is treated. Nausea with or without vomiting is common when the abdomen is treated and occurs sometimes when the brain is treated. Medications are available to help prevent or treat nausea and vomiting during treatment.

Late side effects of radiation therapy may or may not occur. Depending on the area of the body treated, late side effects can include (1):

• Fibrosis (the replacement of normal tissue with scar tissue, leading to restricted movement of the affected area).
• Damage to the bowels, causing diarrhoea and bleeding.
• Infertility (inability to have a child).

Person undergoing radiation therapy does not feel pain/warmth/heat when it’s being actually given. It’s a painless treatment.

Person receiving external RT or brachytherapy (Internal Radiation) does not become radioactive any time during treatment. Radiation one receives gets absorbed in your body tissues and there is no lingering radiation later on. It’s absolutely safe to stay with family and friends while you are on RT.

Only patients receiving RT to head lose their scalp hair (that too usually partially). If you are getting radiation on any other body part, you will not lose your scalp hair. Radiation causes only hair loss in local area being treated with RT. Patient receiving radiation to breast might lose some hair in arm pit or male patients with RT might lose facial/beard/moustache hair.

RT does not cause skin burning, however it does lead to redness, darkening, peeling of skin in the local area being treated. Magnitude of these side effects vary from person to person and also depend on area being treated and dose of RT. These effects are usually temporary and gradually improve after RT completion.