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Potential side effects of radiation therapy for melanoma

Side effects can occur with any type of treatment for melanoma, but not everyone has them or experiences them in the same way. Side effects of radiation therapy will depend mainly on the:

  • size of the area being treated
  • specific area or organs being treated
  • total dose
  • treatment schedule

Radiation therapy damages cancer cells, but healthy cells in the treatment area can also be damaged, even though steps are taken to protect them as much as possible. Different cells and tissues in the body tolerate radiation differently.

Side effects can happen any time during, immediately after or a few days or weeks after radiation therapy. Most side effects go away after radiation therapy is finished. Late side effects can occur months or years after radiation therapy. Some side effects may last a long time or be permanent.

It is important to report side effects to the healthcare team. Many side effects can be relieved by medications, a change in diet or other measures. Doctors may also grade (measure) how severe certain side effects are. Sometimes radiation therapy treatments need to be adjusted if side effects are severe.

The following is a list of general side effects of radiation therapy to the skin. Additional side effects can occur depending on the area treated with radiation therapy.


Fatigue is one of the most common side effects of radiation therapy. Fatigue may be caused by anemia, poor appetite or depression. It may also be related to toxic substances that are produced when cancer cells break down and die. During radiation therapy, the body uses more energy to heal itself, so fatigue will not always be relieved by rest. Making frequent, daily trips for radiation treatments can also be tiring.

Radiation therapy to any area of the body can make a person feel more tired than usual, but is more common when larger areas of the body are treated. Anemia is more likely to occur when the treatment area includes areas where blood cells are formed in the bone marrow, such as the pelvic bones.

Fatigue usually occurs during or after the second week of radiation treatment. Symptoms of fatigue may increase or become more severe over the course of treatment. Fatigue usually goes away gradually after treatment has ended, but some people continue to feel tired for several weeks or months after radiation therapy.

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Skin reactions

Skin may become slightly red and sore during the radiation treatment period. General skin reactions include:

  • redness
  • itching
  • dryness or flaking
  • moistness
  • peeling
  • tenderness or soreness
  • scarring

Most skin reactions occur within the first 2 weeks of receiving radiation treatment. They usually go away a few weeks after treatment, but some skin changes can be permanent. Some people do not experience any skin reactions with radiation therapy.

Once treatment is over, the skin may become crusty and form a scab. When the scab falls off, there will be healthy skin underneath and this area will be more sensitive to sun in the future.

Sometimes skin changes occur after radiation is finished and become long-term (chronic) problems. The skin over the treated area can become thinner and appear:

  • darker or tanned (because the cells that produce skin pigment are affected)
  • smooth, tight and shiny
  • red or flushed (because small blood vessels are widened)

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Hair loss

Hair loss (alopecia) only occurs in the area being treated. Thinning or loss of hair can occur in any area where radiation has been directed. The extent of hair loss and regrowth varies from person to person and depends on the dose of radiation.

Hair loss can begin about 2–3 weeks after radiation therapy starts. Smaller doses of radiation usually result in temporary hair loss, whereas permanent hair loss is more common at higher doses. When hair regrows, usually about 3–6 months after radiation treatment is finished, the colour or texture may be different and it may grow back thinner or patchy.

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