Damage to the muscles

Hypoplasia, or underdevelopment of soft tissue, is the most common late effect of radiation on muscles and soft tissue. Muscles that have been radiated do not grow as large or as strong as muscles that have not been radiated. For some survivors, hypoplasia is a problem more of appearance than function. For survivors who had high-dose radiation many years ago, the weakening of bone and muscle increases with age and can severely impact quality of life.

If you had radiation to one side of the body while you were growing, you may have less muscle and fat tissue in the areas that were irradiated. This can result in the side of your body that was irradiated appearing less developed compared to the side that was not treated. The difference in appearance between the two sides of your body is called asymmetry. The more weight you gain, the more noticeable the difference may become.

Some survivors who had radiation to muscle groups have persistent problems with muscle tone. Occasionally, lack of exercise during years of treatment can also cause loss of muscle tone.

Signs and symptoms of muscle damage

Signs and symptoms of hypoplasia (underdevelopment):

• Decreased muscle mass

• Asymmetry of muscle mass of treated and untreated areas

• Decreased range of motion

• Decreased strength of affected muscles

• Stiffness and pain

Follow-up screening and detection of muscle damage

An evaluation of late effects to the muscles includes a visual inspection of all muscle groups, looking for asymmetry, swelling, atrophy (wasting or thinning of muscle mass), fibrosis (scarring and thickening of muscle tissue), and strength.

Follow-up monitoring by your provider should include:

• careful measurements and comparisons of irradiated and untreated areas

• evaluation of tone, size, and strength for all muscle groups

• range of motion evaluated for affected muscle groups in arms or legs

You should discuss your ability to participate in daily activities such as going to work or school and taking care of your home. Talk about any limitations such as problems walking up stairs. Tell your healthcare provider about what types of exercise you do and how often. If you have late effects to the muscles that alter your appearance, discuss whether this affects your life in any way. Comprehensive care includes helping you adapt to changes in your body’s appearance.

Medical management of muscle damage

Reversal of late effects to the muscles isn’t possible, but trying to prevent worsening is. The primary way to do this is through a reasonable exercise program that works for you and improves your range of motion and muscle strength. A physical therapist can help you design an individualized program to suit your needs.