Radiotherapy in Symptom Management

Question 1

Radiation : MOA

Answer 1

• ionizing radiation damages DNA
• Xrays or linear accelerator
• gamma rays from radioactive source
• Direct damage to DNA:
  
  • base deletions, breaks
• Indirect damage:
  
  • toxic free radicals from interaction of radiation and water
  • damage to endothelial cells
  • apoptosis

Question 2

Radical Radiotherapy

Answer 2

• cure
• minimizing long term damage to normal tissue
• radiation dose is built up with daily treatment over several weeks
• can accelerate or hyperfractionate
• 6-8 weeks in duration

Question 3

Palliative Radiotherapy

Answer 3

• aim is control of symptoms with minimal acute radiation reaction
• majority of tumour cells killed (60-80%) in first 1-2 doses
• short courses, low doses = less acute reaction
• minimizes late damage to normal tissues

Question 4

Radiation treatment planning

Answer 4

• Immobilization:
  
  • face masks, etc
• Treatment volume dosing
  
  • CT sim
• Dosimetric planning
• Verification

Question 5

Types of radiation therapy

Answer 5

• External beam radiation (electrons)
  
  • Xrays
  • linear accelerator
• Brachytherapy
  
  • radiactive sources placed directly onto or into treatment area
  • iridium, cobalt
• Systemic radioisotopes
  
  • target specific tissue or pathophysiology
  • radioiodine for thyroid cancer
  • strontium for bone mets

Question 6

Acute side effects of radiation (during treatment - several weeks)

Answer 6

• from loss of epithelial cells
• skin erythema, desquamation
• mucositis
• esopahgitis
• non infectious cystitis
• GI irritation
• skin infection
• usually recovers in weeks

Question 7

Late side effects of radiation

Answer 7

• Vascular damage, tissue ischemia
• Skin
  
  • atrophy, fibrosis
  • telangectasias, necrosis
• GI tract
  
  • stricture
  • bleeding, telangectasias
  • perforation
  • malabsorption
  • enteritis, colitis, proctitis
• Bladder
  
  • bleeding
  • strictures
  • fistulae
• Oral cavity:
  
  • mucosal atrophy
  • bleeding
  • caries
  • mandibular necrosis
• Lung:
  
  • fibrosis
• Eye:
  
  • cataract, dry eye

Question 8

Management of radiation side effects: SKIN

Answer 8

• desquamation rare in palliative doses
• do not use talcum, gentian violet –> metallic salts increase skin reaction

Question 9

Management of radiation side effects : MUCOSITIS

Answer 9

• chlorhexidine mouthwash
• anticandidals
• NG feeds
• oral hygiene and dental assessment for curative intent radiation
• avoid alcohol and smoking

Question 10

Management of other radiation side effects

Answer 10

• Pneumonitis : steroids and antibiotics
• GI : nausea management
• Cystitis : analgesics, rule out infection, flomax, buscopan

Question 11

Radiotherapy and symptom control : general indications

Answer 11

1. Pain

• Bone
• visceral
• Neuropathic

2. Local pressure

• SCC
• Cranial nerve palsies

3. Obstruction

• Bronchus
• Esophagus
• SVC
• Hydrocephalus
• limb swelling

4. Bleeding

• hemoptysis
• hematuria
• vaginal bleeding
• rectal bleeding

Question 12

Radiation for bone pain

Answer 12

• bone pain
• pressure on nerves
• pathological fracture
• Effective within days to weeks, durable response of months-years
• Can re-treat with good response
• Single fraction :
  
  • more pain flares
  • higher rate of retreatment
• Multiple fractions:
  
  • to treat path fracture
  • spinal cord compression

Question 13

Wide field treatment for bony mets

Answer 13

• multiple sites of disease and pain
• diffuse
• Wide field RT: up to half the body at a time
• Greater toxicity: GI, bone marrow suppression, fatigue, pneumonitis

Question 14

Radioactive isotopes for bony pain

Answer 14

• isotopes concentrate at bone met sites
• focal release of beta particles, gamma release
• Strontium-89
• Samarium
• as effective as EBRT, fewer side effects
• AE : thrombocytopenia, neutropenia
• analgesia onset - MONTHS
• Expensive
• renal excretion, must be continent of urine to prevent contamination

Indications:

• multiple painful bony mets
• local radiation not feasible

Question 15

How does radiation acheive pain control?

Answer 15

• not clear
• tumour shrinkage may not occur
• osteoclast activation?

Question 16

Pain flare after radiation

Answer 16

• first few days
• 1-2 days duration
• dexamethasone
• opioids

Question 17

Radiation for pathological fracture

Answer 17

• if surgery not indicated or possible
• Post operative internal fixation
  
  • prevents progression
• if widespread disease, limited prognosis, good pain control –> no RT

Question 18

Radiation for SCC

Answer 18

• Dexamethasone 4 mg qid
• Lymphoma and SCLC - primary treatment is chemo
• Surgery first if:
  
  • good PPS
  • solitary mets
  • single level cord compression
  • extensive vertebral collapse into spinal canal
• Radiation post op
• primary radiotherapy is surgery not indicated or wanted

Question 19

Radiation for Brain mets

Answer 19

• Dexamethasone 4-8 mg daily
• Solitary brain met - surgery or SBRT and post op RT
• WBRT for mutiple diffuse mets
  
  • palliation of headache, motor and sensory loss, confusin in 80%
  • median survival < 6 months
• brain mets = widespread advanced disease
• Need careful patient selection and discussion of goals of care

Acute toxicity WBRT : alopecia x2-3 months

Long term toxicity WBRT : neurocog impairment

Question 20

Meningeal carcinomatosis and RT

Answer 20

• Pre terminal event
• survival few weeks if untreated
• multifocal radiculopathy, cranial neuropathy, headache, backache
• raised ICP
• breast, lung, leukemia, lymphoma
• WBRT and whole spinal RT extends prognosis from weeks to maybe short months, all taken up with treatment
• Skull case for CN or spinal cord nerve roots for sx control may be indicated

Question 21

Brain mets RT decision algorithm

Answer 21

• Good PPS
  
  • multiple mets
    
    • WBRT
  • solitary /oligomet
    
    • surgical?
    • non surgical - radiosurgery, WBRT
  • lymphoma, SCLC, germ cell tumour
    
    • chemotherapy
• Poor PPS
  
  • supportive care

Question 22

Other neurological symptoms that may benefit from Radiation

Answer 22

• Cranial nerve palsies - skull base effective
• Peripheral nerves - lumbosacral nerve roots, apical lung tumours, brachial pleus, lymph nodes
• Choroidal and orbital mets
• Cerebral lymphoma - HIV, WBRT role in question

Question 23

Obstructive symptoms : SVCO

Answer 23

• Occlusion by external compression
• intraluminal thrombosis
• direct invasion of vessel
• Lung cancer, lymphoma
• Presentation:
  
  • headaches
  • somnolence
  • dizziness
  • edema
  • dysphagia
  • dyspnea
  • cough
  • hoarseness
  • engorgement and dilation of facial veins
  • facial edema

Question 24

SVCO management general

Answer 24

• steroidse
• SVC stent
• Chemo for SCLC germ cell, lymphoma
• Radiotherapy

Question 25

Bronchial obstruction

Answer 25

• central airway obstruction
• bronchial carcinoma, extrinsic compression by mediastinum LN, lymphoma
• dyspnea, cough
• Treatment
  
  • intrinsic tumours
    
    • bronchoscopy with laser or cryo
    • stent
  • Extrinsic tumours
    
    • chemo
    • radiation
    • stent
    • endobronchial radiation

Question 26

Dysphagia and Radiation

Answer 26

• extrinsic compression from esophageal tumour, hypopahrynx, stomach, thymus, thyroid, meadistinal LN
• Radiation:
  
  • useful
  • swallowing improved 80%
  • 2 weeks for efficacy
  • esophagitis AE

Question 27

Urinary tract obstruction

Answer 27

• nephrostomy, ureteric stsents or TURP most appropriate
• radiation alternative if procedure impossible or inappropriate

Question 28

Limb edema and radiation

Answer 28

• venous obstruction, lymphatic obstruction, post radiation
• radiation helpful for axillary, inguinal or pelvic lymphadenoapthy

Question 29

Hydrocephalus

Answer 29

• Obstructive hydrocephalus from primary or secondary tumours
• Posterior fossa or midbrain tumours obstructing aqueduct or 4th ventricle
• leptomeningeal disease

Treatment:

• IV shunt
• if not feasible, palliative radiation

Question 30

Hemoptyis and radiation

Answer 30

• radiation effective 80% control
• no survival advantage
• pulmonary mets more difficult to treat
  
  • harder to ID site of hemorrhage
• may require bronchosopcy to localize site

Question 31

Hematuria and radiation

Answer 31

• must localize bleeding on cysto or CT for treatment planning
• Causes of hematuria:
  
  • tumour bladder
  • cystitis
  • late complication of pelvic rad
  • tumour anywhere in GU tract
• RT:
  
  • hemostasis in inoperable tumours
  • failure of conservative managemnt (TXA, irrigation, etc)
  • SE: diarrhea, nausea, vomiting

Question 32

Uterine and vaginal bleeding : radiation

Answer 32

• uterine tumours
• local infiltration of advanced bladder or rectal ca
• Radiation helpful

Question 33

GI Bleeding and radiation

Answer 33

• large bowel lesions can be radiated
• stomach and small bowel difficult

Question 34

Chest wall and skin lesions - Bleeding

Answer 34

• locoregional recurrence in breast can
• skin nodules
• primary skin cancers

Treatment

• radiation can control growth, bleeding and prevent fungation
• skin nodules reponsive to RT

Question 35

Fungating skin lesions -radiation

Answer 35

• Occurs with superficial tumours
• most common is breast chest wall recurrence
• metastatic LN in neck or groin

Treatment

• radiation best when skin is intact
• can still treat once fungation has occured
• antibiotics, analgesics, antibiotics, skin care

Question 36

Kaposi’s sarcoma

Answer 36

• AIDS
• very radiosensitive - RT can lead to complete regression
• presentation :
  
  • multiple purplish skin plaques
  • also in oral cavity and GI tract

Question 37

Liver mets

Answer 37

• inoperable mets: stereotactic RT helpful
• useful if:
  
  • good PS
  • normal bilirubin
  • not stomach or pancreas cancer
• liver mets = terminal phase advanced cancer
• liver has limited tolerance to radiation

Question 38

Splenomegaly and radiation

Answer 38

• hematologic malignancies (leukemia, NHL, MDS)
• splenectomy preferred management
• radiation in advacned disease or poor PPS
• consider if symptomatic from bulk or hypersplenism (thrombocytopenia and anemia)
• may precipitate pancytopenia

Question 39

Acute radiodermatitis : treatment

Answer 39

• Erythema, edema 1-2 weeks post RT
• desquamation, ulcers
• Treatment:
  
  • no prophlyaxis
  • wash with mild soaps, avoid deodorants, shaving
  • moisturizers
  • no benefit to steroids

Question 40

Chronic radiodermatitis : treatment

Answer 40

• Vascular
• dermal atrophy 4-6 months
• dermal thinning 1 year
• skin necrosis and ulcers

Treatment:

• emollients
• prevention of trauma
• radiation ulcers are treatment resistent
• goal is to prevent infection and pain
• hydrocolloids useful for ulcers

Question 41

Radiation recall

Answer 41

• inflammatory reaction triggered by sytotoxic chemo in previously radiated areas (skin)
• radiation could have been days or years prior
• Presentation
  
  • well circumscribed erythema in previous rad field
  • gemcitabine, anthracyclines, taxanes
• treatment
  
  • stop chemo
  • steroids, NSAIDS