Side Effects of Radiation Therapy
Radiation therapy is the targeted dosing of tumors and cancerous tissue with high-energy beams. This kills cancer cells, but the radiation does not discriminate and will kill healthy cells too. Because of this, radiation has the potential to cause a number of side effects, some serious. The side effects that a patient will experience depend on the type of cancer and where the radiation is done in the body and the type or radiotherapy used.
For patients with mesothelioma, treatment with radiation is often an important part of a multimodal approach. Radiation helps to shrink tumors before surgery and to 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 which must be balanced against the benefits of treatment.
What is Radiation Therapy?
Radiation therapy, or radiotherapy, is one of three main treatment approaches used in all types of cancer. The other two are surgery and chemotherapy and it is not uncommon for patients to undergo all three or a combination of two of these treatment strategies for the greatest effectiveness. Radiation therapy is often used before or after surgery.
Radiotherapy involves using a beam of high-energy radiation to target and kill cancer cells. X-rays, gamma rays, or other types of radiation are produced by a machine, focused into a beam, and aimed at the tumor. Traditionally, this is done externally, so the beam is outside of the body and must penetrate skin and other tissue to target the tumor. The radiation can damage this healthy tissue as much as the cancerous tissue.
More advanced radiation techniques have tried to get around this problem. One strategy involves implanting small, radioactive devices near tumors in the body so that the radiation is limited to a small area. Another is called intensity-modulated radiation and it uses imaging scans and computers to modulate the radiation beam so that it conforms to the exact shape of the tumor and minimizes radiation to healthy tissue. Side effects are less with these types of radiation therapy, but any procedure using radiation may cause some common side effects, regardless of the part of the body targeted
Fatigue is one of the most common side effects associated with radiation therapy. This is more than just feeling tired; it is a deep weariness and lack of energy. Fatigue from cancer treatment can leave patients unable to do normal activities and does not necessarily improve with extra rest or sleep. The good news about this side effect is that it will go away after treatment with radiation is finished. It may take a few weeks afterward to get complete relief. In the meantime, patients are encouraged to get help from loved ones doing daily tasks, to rest as much as possible, and to try to reduce stress.
Irritation at the Treatment Site
Also common with radiation are skin side effects where the beam of radiation penetrates to get to the tumor. Symptoms may include dryness, itches, pealing skin, swelling, irritation, redness, and blistering. Most of these will heal after treatment is over, but in some cases that area of skin may remain permanently slightly darker or more sensitive. Patients may also see hair loss at the site of the radiation treatment, and it usually grows back.
Low-Blood Cell Count
Radiation may reduce the amount of white blood cells and platelets in the bloodstream, although this is rare. White blood cells are part of the immune system, so reduced counts can result in more infections or infections that last longer or are more severe. Platelets are important for blood clotting, so there is an increased risk of bleeding if counts are low. Lowered platelets and white blood cells is more common when chemotherapy is also being administered to a patient.
Side Effects from Radiation to the Chest
For mesothelioma, radiation is most often targeted at the chest cavity to treat pleural mesothelioma, or the abdomen to treat peritoneal mesothelioma. Some side effects are specific to radiation that is aimed at the chest cavity. These may include difficulty swallowing because of swelling in the throat. This can make it difficult to eat, which in turn can lead 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, which can make it difficult to breathe and may cause shortness of breath and coughing. This is called pneumonitis and in most cases it will get better over time. In some cases, however, this condition can be severe, permanently damaging, and even fatal. About one in ten patients will experience chronic, or recurring, pneumonitis as a result of chest radiation. This can be an especially 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, and this can be serious and fatal.
Side Effects from Radiation to the Abdomen
Patients being treated for peritoneal mesothelioma may receive radiation to the abdomen, which causes particular side effects. These include nausea, vomiting, and diarrhea. These are common with radiation to the abdomen, and while uncomfortable, are not usually serious and will get better after treatment. Diarrhea and nausea can both be treated. Drugs may help, as can dietary changes. Getting plenty of fluids is important, especially with diarrhea.
The bladder may be effected by radiation in the abdominal cavity and this can result in bladder inflammation, called cystitis, blood in the urine, or incontinence. All of these 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, and even damage to the pelvic bones. Pain after radiation may also indicate that the cancer is coming back. Pain can be managed with medications or by treating the underlying cause of the pain, such as antibiotics for an infection.
Long-Term Side Effects
Unfortunately, it is possible that radiation therapy will cause long-term damage and resulting side effects that patients will always have to live with. The skin in the area where the radiation is administered, for instance, may be permanently changed. The texture, color, and amount of hair may never change back to what it was before the procedure.
Radiation, especially to the abdomen, has the potential to cause problems with fertility, and these may be irreversible. Sometimes the infertility is temporary, but a patient may never recover fertility. This can be dealt with by freezing eggs or sperm before undergoing treatment. This is especially important for younger patients to consider and to bring up with their doctors before treatment.
For radiation treatment to the chest or abdomen, potentially long-term damage may include lung damage that causes permanent breathing difficulties, permanent narrowing of the esophagus, and permanent damage to the bowels or bladder, which may lead to incontinence or ongoing gastrointestinal issues.
Advances in how radiation is administered to patients are reducing the risks of side effects, but all of these are still possible. Side effects are especially a risk for traditional, external beam radiation. They are less of a risk for intensity-modulated therapy or brachytherapy. If you are facing radiation treatment, make sure you understand what the risks are, how to minimize them, and that you feel comfortable that the benefits of treatment are worth the risks.
Page Edited by Dave Foster
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