Radiation Side Effects and Syndromes

Original Editors -Alicia Dupilka & Kristin Gramling from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Kristin Gramling, Alicia Dupilka, Lucinda hampton, Vidya Acharya, Kim Jackson, Admin, Elaine Lonnemann, WikiSysop, 127.0.0.1 and Wendy Walker

Definition/Description                                                   

Radiation therapy works by delivering high doses of ionizing radiation that damage cancer cell DNA, preventing multiplication and ultimately causing cell death. While this targeted approach affects malignant cells more severely than healthy tissue, the treatment process requires days or weeks before sufficient DNA damage accumulates to eliminate cancer cells.

The Clinical Reality for Physiotherapists

With nearly two-thirds of all cancer patients receiving radiation therapy, physiotherapists increasingly encounter clients experiencing radiation-related complications. These side effects manifest as physical problems including pain, fatigue, muscle weakness, contractures, lymphedema, and radiation fibrosis syndrome (RFS) - all conditions that significantly impact patients' physical, emotional, and practical functioning.

Treatment Approaches and Combinations

Radiation therapy serves multiple clinical purposes:

• Primary curative treatment (such as head and neck cancers)
• Adjuvant therapy (reducing recurrence rates after local breast cancer surgery)
• Palliative care (managing pain from bone metastases)
• Non-malignant conditions (Graves thyroiditis, keloid scarring)

The therapy may be delivered independently or combined synergistically with chemotherapy or immunotherapy, with the specific approach determined by the disease type and cancer characteristics.

Your Role in Comprehensive Care

Early recognition and prompt physiotherapy management of acute radiation side effects prevents long-term complications. Your rehabilitation services focus on improving strength and stamina, resolving pain, and addressing site-specific problems while providing essential education on skin care, physical activity maintenance, and nutrition.

• There are no good estimates of how many of these patients will develop complications due to the radiation therapy

Techniques

Radiotherapy is customarily divided into three main categories:

1. External beam radiotherapy (EBRT) where a medical linear accelerator (linac) directs ionising radiation at the tumour from outside the body eg
   • Conventional Radiation Therapy. This refers to the old techniques of radiation therapy where treatments would be planned by defining a limited number of beams with the boundaries delineated on orthogonal x-rays of the patient. It has been largely replaced by other highly conformal external beam radiation therapies, which use CT images to plan the treatment. Examples of these newer techniques include: three-dimensional conformal radiation therapy (3D-CRT); intensity-modulated radiation therapy (IMRT); stereotactic radiosurgery; electron therapy; particle (hadronic) therapy.
2. Sealed source radiotherapy (brachytherapy) where a radiation source(s) is placed, under the guidance of imaging, within or next to the area requiring treatment.
3. Unsealed source radiotherapy (systemic radioisotope therapy) where a radioisotope is delivered through: infusion e.g. for neuroendocrine tumours ; ingestion e.g for thyroid cancer.

Characteristics/Clinical Presentation

Side Effects

Depend on the area of the body being treated, dose given per day, total dosage, general medical condition and other treatments being given.

1. Acute radiation injury
   • Nausea, malaise, dysphagia, vomiting immediately following irradiation
   • Erythema
   • Mucosal inflammation (stomatitis, esophagitis, enteritis, etc.)
   • Bone marrow damage: Anaemia, thrombocytopenia, and/or leukocytopenia (pancytopenia)
   • Infection due to immunocompromise
   • Early radiation-induced lung injury (radiation pneumonitis): Dyspnea, dry cough, hemoptysis, and fever may occur several weeks following radiation.
   • Partial respiratory insufficiency is an early sign.
2. Chronic radiation damage
   • Radiation Fibrosis Syndrome
   • Late radiation-induced lung injury (radiation fibrosis)
   • Bone: fractures
   • Bone marrow damage: anemia, thrombocytopenia, and/or leukocytopenia (pancytopenia); Infection due to immunocompromise
   • Heart: increased risk of myocardial infarction
   • Gastrointestinal: impaired function
   • Thyroid: impaired function (hypothyroidism)
   • Impaired fertility: Fibrosis in ovaries involving amenorrhea; Azoospermia
   • Radiation of the head: Leukoencephalopathy; Hormone imbalances and their outcomes, such as stunted growth due to low growth hormone levels
   • Xerostomia
   • Malignancies: especially leukemias, MDS, lymphoma, thyroid cancer

Common general side effects of radiation therapy

Fatigue: Is different from the fatigue of everyday life, and it might not get better with rest. It can last a long time and can get in the way of usual activities. It will usually go away gradually after treatment ends. It’s very common for people with cancer and with radiation therapy. Usually starts after a few weeks of radiation therapy as a result of radiation treatments which destroys some healthy cells as well as the cancer cells. Fatigue usually gets worse as treatment goes on. Stress from being sick and daily trips for treatment can make fatigue worse. Managing fatigue is an important part of care.

Radiation Dermatitis/ Erythema: Skin in the radiation treatment area might look red, irritated, swollen, blistered, sunburned, or tanned. After a few weeks, the skin might become dry, flaky, or itchy, or it may peel.

Hair loss: Radiation therapy can cause hair to be thinned or lost in the area being treated. Eg radiation to the head may cause hair loss on your head (even eyebrows and lashes). Most people find that their hair grows back after treatment ends. When it does grow back, the hair may be thinner or a different texture than it was before.

Low blood count: Rarely, radiation therapy can cause changes in blood count levels, making clients more vulnerable to bleeding and infections. If blood tests show low blood counts, treatment might be stopped for a week or so to allow blood counts to return to normal (this side effect is more likely if you’re also getting chemotherapy).

Specific side effects of radiation therapy

Gastrointestinal

• Radiation Esophagitis: often involved in radiation treatment for lung cancer especially when a chemosensitizer is also used. Symptoms usually resolve in 1 to 3 weeks after radiation is finished. Symptoms: abnormal peristalsis, odynophagia (pain with swallowing) and dysphagia
• Radiation Enterocolitis: often results in fibrosis leading to strictures in the intestines, bowel obstruction, fistulas with abscess formation, ulceration with bleeding and malabsorption
• Acute or Chronic Radiation Enteritis.

Pulmonary

• see Pulmonary Complications of Cancer

Cardiovascular

• Radiation Heart Disease - may result in pericarditis, Coronary artery disease, myocardial disease and aortic-valve disease

Musculoskeletal

Connective Tissue Involvement - late changes such as fibrosis, atrophy and contraction is common especially in collagen

• In bones and limbs it can cause weakness, limb-length discrepancies and scoliosis
• It can result in edema and decreased range of motion 
• It can cause pelvic adhesions that result in painful motion and sometimes plexopathy (a disorder affecting a network of nerves in the brachial or lumbosacral plexus, resulting in pain and loss of motor control).
• In the circulatory and lymphatic system it can cause loss of elasticity on contractility of vessels. Even though the actual lymph vessels may maintain their shape, fibrosis in the surrounding tissue can inhibit growth of the vessels into tissues that need to be healed.

Nervous System      

• Acute symptoms: occur during treatment and include debilitating fatigue; cranial radiation may result in short-term memory loss, changes in behavior and cognition, decreased appetite, dry skin, hearing loss, hair loss and decreased salivation
• Subacute symptoms: occur 1 to 4 months after treatment and are not as common.  Radiation to the cervical spine may result in subacute myelopathy (Lhermitte's sign).  Radiation to the brainstem may result in ataxia, nystagmus and dysarthria
• Chronic symptoms: occur months to years after therapy and can include damage to the cerebral vasculature leading to coronary artery disease, transient ischemic attacks, stroke or myocardial infarction.
• Radionecrosis - results from whole-brain radiotherapy.  Secondary tumors may develop and the hypothalamic system may be affected. Symptoms: headache, changes in cognition and personality, focal neurological deficits and seizures. 
• Myelopathy - results from radiation of the spinal cord.  May present as Brown-Sequard syndrome or motor neuron syndrome.
• Plexopathy - results from damage to the brachial and lumbar plexuses.  Symptoms may include paresthesias, motor deficits, lymphedema and pain.

Radiation Fibrosis Syndrome (RFS)

When radiation hits healthy tissue, it triggers a cascade of fibrin overproduction that progressively damages structures within the treatment field. This isn't just collateral damage - it's radiation fibrosis syndrome (RFS), and it's reshaping how we approach post-cancer rehabilitation.

The Clinical Picture:

• Tissue shortening and muscle contractures with atrophy
• Bone weakening and fracture vulnerability
• Cardiovascular, pulmonary, and neurological complications
• Lymphedema development

Timeline Reality Check RFS symptoms can surface anywhere from weeks to years post-treatment - and they're progressive. Early intervention isn't just beneficial; it's critical.

Your High-Priority Patients Head and neck cancer survivors face the highest RFS risk. High-dose radiation to anatomically complex regions means the structures they need for eating, speaking, and moving their head are under siege. These patients need you before problems become permanent.

Bottom Line: You're not just treating existing dysfunction - you're preventing functional decline. RFS management represents a shift from reactive to proactive physiotherapy, where your expertise can dramatically impact long-term outcomes.

Some examples of the problems encountered include:

• Decreased ability to fully open the mouth (trismus)
• Neck pain and tightness (cervical dystonia)
• Lymphedema (swelling)
• Difficulty with speech and swallowing

The treatment for RFS depends upon the symptoms and side effects the patient is having. Physical therapy, occupational therapy, speech and swallow therapy, and surgery may all play a part in treatment for RFS.

Medical Management

• Clinical trials to learn how to use radiation therapy more safely and effectively are being conducted by doctors and scientists.
• Working on improving image-guided radiation.
• Research is also being done on radiosensitizers and radioprotectors.
• The use of carbon ion beams is still being investigated and remain experimental. This type of therapy are not currently available in the US.

Physical Therapy Management

Cancer and treatment can cause physical problems including, but not limited to, pain, fatigue and muscle weakness. These often interfere with life in physical, emotional and practical ways.

Physiotherapy rehabilitation services can work on: improving strength and stamina; pain resolution; site specific problems eg contractures, lymphedema, RFS; education re skin care, importance of remaining physically active and good nutrition.

• Physical therapists should always wash their hands before treating a patient who has undergone radiation therapy to protect that client from possible infection.

Skin Care

• Avoid use of alcohol/drying agents, lotion, gel, or oil. Creams and gels can increase the dosage received on the skin and increase the likelihood of side effects
• Do not wash away markings of the targeted area
• Position the patient so they are not lying on the targeted area
• Avoid exposing the patient to sources of heat, including direct sunlight and modalities
• Monitor wound healing

Musculoskeletal 

• If adhesions are present in the hip after radiation of the pelvis, be sure to incorporate range of motion activities; early intervention is important to prevent contractures and restrictive scarring.
• Post-radiated tissue can tear when stretching so it is important to observe for blanching of the skin during stretching and not to stretch beyond that point.  Stretching should be continued 18 to 24 months after radiation therapy has been discontinued.

Nervous System 

• Anyone with neurological signs or symptoms of an unknown cause should be asked about a previous history or cancer and radiation therapy

Infection

• Therapists should observe carefully for signs of infection in patients who have undergone radiation treatment.  The first and only sign may be a fever because the patient may be immunosuppressed and their body cannot create a normal inflammatory response.

Exercise 

• A successful protocol should include patient education, exercise evaluation and an individualized exercise prescription. - Therapists must monitor vital signs in patients who have undergone radiation treatment because radiation and chemotherapy can leave the lungs and heart tissue permanently scarred. Patients should be taught to monitor their own vitals including heart rate, respiration rate and rate of perceived exertion (should not exceed 15 to 17) and taught to detect signs of complications such as dyspnea, pallor, excessive perspiration, or fatigue while exercising.  Patients should be told not to exercise within 2 hours of chemotherapy or radiation therapy because it increases the circulation and may increase the effects of the treatment.
• Studies have shown low to moderate intensity aerobic exercise during the same weeks of radiation treatment can help improve physical function and lower subjective levels of fatigue, anxiety, depression and sleep disturbances.

Management of Syndromes Associated with Radiation Fibrosis Syndrome

  Physical Therapy is usually the first line of treatment for the dysfunctions listed below.

• Neck Extensor Weakness - emphasize postural retraining through core strengthening, flexibility of the shoulder musculature, and strengthening the cervicothoracic and rotator cuff muscles.  This will help reduce energy demands and pain.  It is also important to develop a long-term home exercise program
• Shoulder Pain and Dystonia - treated through conservative measures because shoulder surgery should be avoided in patients with RFS because damage of the neruomuscular structures often results in poor surgical outcomes.  Work on core strength and posture, neck extensor and rotator cuff strength and stretching of pectoral girdle musculature in order to try to restore normal anatomical alignment of the shoulders. There is a potential long-term benefit if the patient consistently follows a home exercise program.
• Cervical Dystonia - the goal is to restore and maintain neck range of motion and a long-term home exercise program should be utilized.
• Trismus - Literature is limited but a variety of jaw-opening devices are available to help treat trismus.

Resources

Radiation Side Effects Worksheet http://www.cancer.org/acs/groups/content/@nho/documents/document/acsq-009503.pdf