Radiotherapy (rays): side effects


What is it about ?

When a malignant tumor is found, the person usually does not have many or no symptoms at all at first. But, once she starts radiotherapy (the rays), she can be overwhelmed by the unpleasant side effects of the treatment. Radioactive rays target a specific point in the body to destroy malignant cancer cells. Radiotherapy can be administered both outside the body (external radiotherapy) and inside the body, through certain instruments (internal radiotherapy). Unfortunately, because radioactive rays cannot tell the difference between malignant cells and healthy cells, they can also damage healthy cells. As the rays are directed at a specific point to be treated, the side effects are often local.

How to recognize them?

In the case of radiotherapy, the first symptoms appear within a few minutes or a few hours after the session. Symptoms after high doses of radiation are nausea, fatigue, loss of muscle strength, and confusion. A person who has no symptoms at first may, a few days later, develop nausea, diarrhea, damage to the lining of the intestines, and bleeding. This phenomenon is known as gastrointestinal syndrome.

Besides the well-known hair and hair loss, the rays can also cause canker sores in the mouth, skin problems, nausea, nerve problems (tingling and numb feeling in the hands and feet), a risk increased infections, etc. These can be serious complications that can affect the quality of life.

Skin lesions
Skin lesions appear after a while and their intensity ranges from mild to severe. Mild skin lesions are redness that lasts 2 to 3 weeks after starting treatment. A mild reaction will usually go away on its own within 2 to 4 weeks. Serious reactions, such as burns, should be treated.

Late symptoms include thinning of the skin and dilation of blood vessels. The function of the glands that make sweat (sweat (or sweat) glands) decreases and the skin becomes thin and dry. Scar tissue can form: the skin becomes harder and loses its elasticity.

Hair and / or body hair in the irradiated area begins to fall out 3-6 weeks after starting treatment. As a rule, they will grow back later, sometimes taking on different colors or a more frizzy appearance. The start of regrowth depends on the dose of radiation received.

Mucosal lesions
Depending on the area irradiated, different types of mucous membranes can be irritated by the rays. Canker sores (inflammation of the lining of the mouth) can develop, as can inflammation of the esophagus or irritation of the lining of the stomach and intestines leading to nausea and diarrhea. Narrowing can appear in the intestine for up to several years after radiation therapy to the intestine.

Other affected organs
In growing children, disturbances in the growth of bone and cartilage tissue are seen in areas that have been exposed to doses of radiation high enough to destroy a tumor. The rays directed at the head and brain can slow mental development, especially in small children.

Radiation therapy to the salivary glands results in a dry mouth.

Irritation of the bladder is often manifested by the need to urinate often and, sometimes, by pain.

Radiation therapy targeting the eye area causes conjunctivitis (inflammation of the conjunctiva). Cataract is a late effect of irradiation of the eyes.

Some kind of pneumonia can develop 2 to 6 months after radiation therapy for lung cancer. If there is extensive scar tissue in the lungs, it may remain visible on an x-ray for several years.

The kidneys can shrink and scars can form. Most of the time, kidney damage is so low that it doesn’t cause symptoms.

Radiation therapy given to the area of ​​the heart can cause inflammation and scarring. In the worst case, the membrane around the heart (the pericardium) can become too narrow for the heart over time.

The reproductive organs (ovaries and testes) are very sensitive to radiation and are already damaged with relatively low doses of radiation. So there may be a decrease in fertility. Despite everything, you will need to use contraception if necessary.

If the tolerated dose of radioactive rays to the spinal cord is exceeded, there is a risk of weakening the legs. The effect begins to be felt a few months after treatment and is difficult to distinguish from symptoms caused by a tumor.

Side effects on the blood and lymphatic system
After radiation therapy to half or the whole body, white blood cells, platelets, and sometimes red blood cells may be missing.

Radioactive rays also have an impact on the lymph nodes, which drain fluid throughout the body. Radiation therapy to the head can cause swelling of the head (edema) and increased pressure in the brain.

Others
The occurrence of fatigue and psychological symptoms is variable. It is difficult to assess whether these complaints are due to radiation therapy or to the disease itself.

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Source

Foreign clinical practice guide ‘Management of adverse effects of radiotherapy’ (2000), updated on 04.05.2017 and adapted to the Belgian context on 12.10.2019 – ebpracticenet