Background… • Ionising radiations like X rays, electrons,
protons, alpha particles
• The effects of radiation result mainly from DNA damage either directly or through generation of free radicals from water molecules
Background
• Radiotherapy delivered to around half of cancer patients , is a vital part of curative treatment in around 40% patients
• More curative/contributive towards cure than chemotherapy, much lower acute mortality
• Late effects can be severe but usually well understood and have long history
Severity of reaction depends on
• Total Dose and dose per fraction
• Size of the field
• Total duration of treatment
• Tissue sensitivity
‘4 Rs’ of Radiotherapy- Repair, Repopulation, Redistribution, Re-oxygenation
Severity of reaction depends on
• Co-Morbidities-
Inflammatory Bowel Disease
Connective Tissue Diseases (Scleroderma, SLE)
DNA repair disorders (Ataxia Telangiectasia,
Fanconi Syndrome)
• Concurrent chemotherapy
Classification
• Acute vs. Late Acute effects within days to weeks. More prominent in
fast dividing/rapidly regenerating tissues (Skin, GI tract)
Late effects over months to years in both types
May be very important in slow responding tissue e.g.
Spinal Cord, Kidneys, Lungs
• System/Tissue involved Skin, Mucosa, GI tract, CNS, Kidneys, Lungs etc.
General Principles- Acute
• Resuscitate
• Rehydrate
• Replace electrolytes
• Reduce Transit
• Keep clean
• Control Pain
General Principles- Late
• Supportive Care
• SALT
• Physiotherapy
• Palliative care referral
• Nutritional Support
• Other specialists, eg. Chest Physicians, Endocrinologists
• Late Effects Clinic
Skin
RTOG Grade
Definition
0 No change over baseline
1 Follicular, faint or dull erythema/ epilation/dry desquamation/ decreased sweating
2 Tender or bright erythema, patchy moist desquamation/ moderate oedema
3 Confluent, moist desquamation other than skin folds, pitting oedema
4 Ulceration, haemorrhage, necrosis
Skin
• Significant in
Breast
Vulva
Head and Neck
Rectum/Anus
Skin Cancers
• Less common with MV radiotherapy
• Visible by 2nd or 3rd week of radiotherapy
Management
• Avoid direct sunlight
• Gentle Washing with non perfumed soaps and shampoos, lukewarm water
• Use plenty of moisturiser- water based, non perfumed
• Dry shaving- electric razor
Management
• Specific treatment for desquamation: Hydrocortisone for itch, Flamazine to prevent infections
• Simple, non adhesive dressings
• Treat infection, analgesia (WHO pain ladder-nonopioids e.g. Paracetamol, then mild opioids e.g. Codeine, then strong opioids such as Morphine)
Oral Mucositis
WHO Grade
Definition
0 No change over baseline
1 Soreness with erythema
2 Erythema, ulcers, can eat solids
3 Ulcers, liquid diet only
4 Alimentation not possible
Oral Mucositis
• Common with Head and Neck RT
• Starts within 12-14 days
• Often mistaken for oral thrush by junior ward staff
• Can last for several weeks post RT completion
Management
• Careful Oral Hygiene- Soft tooth brush, gentle toothpaste, alcohol free mouthwash
• Saline mouthwash
• Pharmacological management- Difflam mouthwash and spray , Bioxtra mouthwash, toothpaste and gel
Management
• Soluble Aspirin mouthwash- 300 mg tds in lukewarm water
• Alcohol free Oramorph topically, analgesia according to pain control ladder
• Treat infections- Fluconazole, Acyclovir, Oral antibiotics, Chlorhexidine mouthwash
• Maintain nutrition- Regular weight checks, Dietary review, PEG feed
Radiation Pneumonitis
• Lung Cancer
• Breast Cancer
• Lymphomas
• Oesophageal Cancers
• Clinically evident radiation Pneumonitis
in 5-15% patients receiving thoracic RT
• 60% patients will have asymptomatic radiological changes
Radiation Pneumonitis- Risk Factors
• V20- Volume of normal lung getting >20 Gy- risk high if >35%
• Concurrent chemotherapy
• Pre existing COPD, Pulmonary Fibrosis- FEV1 >40% predicted or 1L, TLCO >50%
• Connective tissue diseases
• Heavy smoking history
Symptoms
• Usually acute phase occurs a few weeks after completion of radiotherapy (4-12 weeks)
• Symptoms typically include
Cough
Dyspnoea (exertional or at rest)
Low grade fever
Chest discomfort and pleuritic pain
Hypoxia
• Over time, may progress to irreversible fibrosis
Investigations
• CXR- Often non-specific. Airspace opacities common. Pleural effusions or atelectasis may be seen. Changes often do not follow anatomical boundaries- might have straight edges
• HRCT- The two most common findings are ground-glass opacities and airspace consolidation
• PFTs- Reduced Lung Volumes, Reduced Transfer Factor
Treatment
• Steroids, example- Prednisolone 40 mgs for 3-4 weeks, then taper slowly over several weeks
• Antibiotics, might help if there is an element of coexisting infection
• Supplemental Oxygen for Hypoxia
• Symptomatic treatment- home oxygen, pulmonary rehab for Lung Fibrosis
GI toxicities
• GI tract vulnerable as contains many rapidly proliferating cells
• GI tract irradiation may result in- Oesophagitis- retosternal burning, dysphagia,
odynophagia. Onset usually after 20 Gy
Nausea and Vomiting- release of serotonin by cell death
in GI mucosa
Diarrhoea
Proctitis- diarrhoea, tenesmus, urgency, bleeding
Management
• Oesophagitis Analgesia for pain control
Barrier- Mucilage, Alginates- Gaviscon
Local Anaesthetic- Oxtecaine/Antacid
Proton Pump Inhibitors
Soft, Bland food, dietary supplementation
Treat Infections, eg Candida
Management
• Diarrhoea Rehydrate, correct electrolyte abnormalities
Rule out infection (C.Diff toxin, stool culture & viral testing)
Exclude other causes- laxatives, PPI, other meds
Exclude overflow diarrhoea
Symptomatic Relief- Loperamide, Codeine
Rectal steroids- (Colifoam/Predfoam)
Management
• Nausea and Vomiting
May be caused by RT to the GI tract or Brain
General principles-
Rehydrate: may need intravenous fluids.
Correct electrolytes
Antiemetics- 5HT3 antagonists, Domeperidone, Cyclizine
May benefit from steroids (Dexamethasone 4-8 mg daily)
Neurological Toxicity
• Acute Whole brain radiotherapy- during or shortly after
finishing RT
Caused by cerebral oedema secondary to disrupted
blood brain barrier
Symptoms- Headaches, drowsiness, seizures, worsening
neurological deficits
Managed by starting steroids (or increasing steroid dose)
Example Dexamethasone 4mg-8 mg PO BD
Neurological Toxicity
• Subacute Somnolence syndrome- occurs 1-6 months after finishing
RT (typically 6 weeks)
Features- somnolence, headaches, irritability
Treatment with steroids: may reduce duration. Usually
settles over weeks to months
Finally… • Newer radiation techniques (IMRT, IGRT)
• Much more conformal, possible to reduce doses to surrounding tissues and organs at risk
• Reduced acute and late toxicities
BUT- low dose “splash” to a higher volume-
long term effects unknown
To Summarise…
• Radiotherapy is a vital component of cancer treatments
• Acute and long term toxicities common but usually mild, self limiting and manageable
• General principles to manage acute toxicities
• We are always available to offer advise and help