What are the side effects of radiation treatment?

Side Effects of Radiation Therapy

Radiation therapy commonly causes both acute and late toxicities affecting multiple organ systems, with severity depending on radiation dose, treatment volume, fractionation schedule, and individual patient factors. 1

Acute Side Effects (During Treatment and Within 3 Months)

Skin Reactions

• Radiation dermatitis: Occurs in majority of patients, with severity ranging from:
  • Grade 1: Mild erythema, dry desquamation
  • Grade 2: Moderate erythema, patchy moist desquamation
  • Grade 3: Confluent moist desquamation
  • Grade 4: Skin necrosis or ulceration 1
• Management includes:
  • Gentle washing with mild, unscented soap
  • Moisturizers for Grade 1
  • Topical steroids and wound care for Grades 2-4 1

Gastrointestinal Toxicity

• Nausea, vomiting, diarrhea, abdominal pain
• Highest incidence during first, second, and fifth weeks of treatment 1
• Management:
  • Antiemetics for nausea/vomiting
  • Anti-diarrheals for loose stools
  • Dietary modifications 1
  • For esophagitis: Dietary modification, proton pump inhibitors, promotility agents, viscous lidocaine 2

Pulmonary Effects

• Radiation pneumonitis typically occurs 2-6 months after treatment
• Symptoms: Nonproductive cough, exercise-induced dyspnea, low-grade fever, chest pain 3
• Treatment: Oral prednisone, pentoxifylline, symptomatic treatment (inhaled β2-mimetics, oxygen supplementation) 3, 2

Hematologic Toxicity

• Lymphopenia, granulocytopenia, thrombocytopenia
• Predictable decline in lymphocytes within 24-48 hours after exposure 1
• Management: Blood count monitoring, growth factors for severe cytopenias, transfusion support 1

Fatigue

• Most common symptom during cancer treatment
• Assessment using 10-point Numeric Rating Scale (mild, moderate, severe) 3
• No specific drug therapy recommended for cancer-related fatigue
• Psychostimulants, antidepressants, and acetylcholinesterase inhibitors have not shown consistent benefit 3

Late Side Effects (Months to Years After Treatment)

Cardiovascular Effects

• Can develop years after treatment, especially with chest radiation
• Includes coronary artery disease, valvular disease, pericardial disease, conduction abnormalities 3
• Risk factors: Hypertension, diabetes, dyslipidemia, obesity 3
• Annual follow-up recommended with ECG or echocardiogram as clinically indicated 3

Neurocognitive Effects

• Occurs in up to 90% of patients with brain metastases 1
• Management approaches:
  • Pharmacological: Donepezil, memantine, methylphenidate, modafinil
  • Non-pharmacological: Cognitive rehabilitation, compensatory strategies 1

Secondary Malignancies

• Increased risk of second malignant tumors after radiation therapy 1, 4
• Risk increases with time after treatment
• Regular screening and surveillance recommended

Genitourinary Effects

• Urinary urgency, dysuria, nocturia, vaginal stenosis
• Management:
  • Symptomatic treatment for urinary symptoms
  • Vaginal dilators for stenosis (though compliance issues may limit effectiveness) 3, 1
  • For radiation cystitis: Anticholinergic agents, phenazopyridine 2

Sexual Dysfunction

• Erectile dysfunction in men
• Vaginal stenosis and dryness in women
• Management: Phosphodiesterase type 5 inhibitors for ED, vaginal dilators for stenosis 2

Bone and Soft Tissue Effects

• Radiation can affect bone marrow stroma directly 3
• Risk of osteoporosis and fractures
• Fibrosis of soft tissues

Prevention Strategies

1. Advanced Radiation Techniques:

   • Intensity-modulated radiotherapy (IMRT)
   • Volumetric modulated arc therapy (VMAT)
   • Image-guided radiotherapy (IGRT)
   • These techniques improve precision and reduce toxicity 1

2. Treatment Planning:

   • Careful planning to minimize exposure to normal tissues
   • Adherence to dose constraints for organs at risk 1
   • Limiting treatment duration (complete within 8 weeks) 3

3. Patient-Specific Considerations:

   • Smoking cessation (decreases cough and dyspnea) 3
   • Exercise training may improve quality of life and restore functional capacity 3
   • Special attention to patients with pre-existing conditions (e.g., interstitial lung disease) 3

Clinical Pearls

• Side effects are multifactorial, with contributions from baseline patient characteristics and other oncologic treatments 5
• Regular assessment of toxicities using specific grading scales (RTOG or CTCAE) helps early recognition and management 1
• Long-term follow-up is essential for cancer survivors to monitor for late effects 1
• A multidisciplinary approach is recommended for management of complex late toxicities 1

Remember that radiation side effects vary significantly based on the treatment site, dose, and individual patient factors. Early recognition and management of these effects can significantly improve quality of life and treatment outcomes.