Side Effects of Radiation Therapy

Radiation therapy or radiotherapy uses targeted ionizing radiation to kill malignant cells. However, radiation doesn’t discriminate between cancer cells and healthy cells. Therefore, radiation potentially causes a number of side effects, some of which can be serious. A number of factors affect how  patient will respond to radiation therapy, including the type of cancer, the part of the body targeted by radiation, and the type of radiotherapy used.

For mesothelioma patients,  radiation therapy is often an important part of a multimodal treatment approach. Radiation helps shrink tumors before surgery and can prevent or delay recurrences after surgery. Radiation to the abdomen for peritoneal mesothelioma and to the chest for pleural mesothelioma can cause significant side effects. These side effects must be balanced against the benefits of treatment.

What is Radiation Therapy?

Radiation therapy is one of three main approaches to cancer treatment, which also includes surgery and chemotherapy. It is not uncommon for patients to undergo a combination of these strategies during the course of treatment. Radiation therapy is often used before or after surgery.

Radiotherapy uses a beam of high-energy radiation to target and kill cancer cells. A machine produces X-rays, gamma rays, or other types of radiation and focuses this energy into a concentrated beam which is then aimed at the tumor. Traditionally, an external beam is used which must penetrate the skin and other tissue to reach the cancerous tissue. In the process, the radiation can damage healthy tissue as much as cancerous tissue.

More advanced radiation techniques attempt to avoid this problem. One innovative strategy implants small, radioactive devices near tumors in the body, limiting the area affected by the radiation. Another technique, called intensity-modulated radiation, uses imaging scans and computers to modulate the radiation beam to conform to the exact shape of the tumor. This minimizes the radiation’s affect on healthy tissue. These techniques minimize side effects, although any radiation procedure may cause some common side effects, regardless of the part of the body targeted.

Fatigue

Fatigue is one of the most common side effects associated with radiation therapy. More than just being tired, fatigue caused by radiation therapy is a deep weariness and lack of energy. Fatigue from cancer treatment can leave patients incapable of performing normal activities and does not necessarily improve with extra rest or sleep. Fortunately, this side effect will go away after treatment, although it may take several weeks to find complete relief. In the meantime, patients are encouraged to get help from loved ones, rest as much as possible, and reduce stress.

Irritation at the Treatment Site

Skin side effects are also common with radiation. The skin is affected as the radiation beam penetrates on its way to the tumor. Symptoms include dryness, itches, pealing skin, swelling, irritation, redness, and blistering. Most of these will heal after treatment is completed. However, in some cases, skin may remain permanently sensitive or discolored. Patients may also see hair loss at the treatment site, although this usually grows back in time.

Low-Blood Cell Count

Although rare, radiation may reduce the amount of white blood cells and platelets in the bloodstream. White blood cells are part of the immune system and reduced counts can result in increased infections. Platelets are important in clotting. When platelet counts are low, there is an increased risk of bleeding. Lowered platelets and white blood cells is more common when patients are also being treated with chemotherapy. .

Side Effects from Radiation to the Chest

For mesothelioma, radiation treatment typically targerts the chest cavity to treat pleural mesothelioma or the abdomen to treat peritoneal mesothelioma. Some side effects are specific to radiation aimed at the chest cavity. These swelling in the throat which makes eating and swallowing difficult. In turn, this can contribute to malnutrition or weight loss. Patients should avoid foods that irritate the throat and eat soft foods and liquid foods such as nutritional shakes.

Radiation to the chest may also cause inflammation in the lungs resulting in difficulty breathing, coughing, and shortness of breath. Called pneumonitis, this condition typically improves over time. In some cases, however, this condition can be severe, permanently damaging, and even fatal. Approximately one in ten patients will experience chronic pneumonitis as a result of chest radiation. This can be a serious risk for someone with pleural mesothelioma receiving radiation after an extrapleural pneumonectomy, as these patients are left with just one lung. Rarely, radiation may also damage the heart, which can be serious and fatal.

Side Effects from Radiation to the Abdomen

Patients with peritoneal mesothelioma may receive radiation to the abdomen, which causes specific side effects including nausea, vomiting, and diarrhea. Common with abdominal radiation treatment, these uncomfortable side effects are not usually serious and subside after treatment. Drugs and dietary changes can be used to ease diarrhea and nausea. Staying hydrated is important, especially with diarrhea.

The bladder may be effected by radiation in the abdominal cavity, resulting in bladder inflammation, blood in the urine, or incontinence. These side effects can be uncomfortable, inconvenient, and even painful. Urination may be accompanied by burning and stinging. Medications and other treatments may help relieve these side effects.

Pain is also a common side effect of abdominal radiation. The pain may be caused by a number of factors, including infections, cramps in the bowels, constipation, or damage to the pelvic bones. Pain after radiation may also indicate a cancer resurgence. Pain can be managed with medications or by treating underlying causes of pain.

Long-Term Side Effects

Unfortunately, radiation therapy can cause long-term damage. The skin in the area where radiation is administered, may be permanently changed. The texture, color, and amount of hair may never return to normal.

Radiation, especially to the abdomen, can potentially cause fertility issues which may be irreversible. Before beginning radiation treatment, patients may choose to freeze eggs or sperm for later use. his is especially important for younger patients.

Radiation treatment to the chest or abdomen can potentially result in long-term damage to the lungs. This damage can cause permanent breathing difficulties,narrowing of the esophagus, and damage to the bowels or bladder, which may lead to incontinence or ongoing gastrointestinal issues.

While advances in radiation therapy are reducing side effects, they are not completely eliminated. Side effects are especially a risk for traditional, external beam radiation. Risks are reduced for intensity-modulated therapy or brachytherapy. If you are facing radiation treatment, it is important to understand the risks and how to minimize them. Be sure to express any concerns or questions to your doctor before beginning treatment.

Page Edited by Patient Advocate Dave Foster

Dave has been a mesothelioma Patient Advocate for over 10 years. He consistently attends all major national and international mesothelioma meetings. In doing so, he is able to stay on top of the latest treatments, clinical trials, and research results. He also personally meets with mesothelioma patients and their families and connects them with the best medical specialists and legal representatives available.

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