14.3 (12.3) Radiotherapy in symptom management Flashcards
What are two types of damage caused to DNA by ionizing radiation?
Which is more important to controlled tumor growth?
Radiation-> direct and indirect damage to DNA
Direct damage = base deletions, breaks in the DNA chain
Indirect damage = results from toxic FREE RADICALS produced from the interaction between radiation and water molecules in cells
- Indirect damage is the more important cause of cell death
- with very high doses (>10Gy) damage to endothelial cells may occur which may cause cell death from damage to blood supply
List 4 types of particle radiation therapies
- Electrons - used to treat superficial sites
- Beta particles - i.e. systemic Strontium
- Alpha particles - i.e. systemic Radium
- Proton therapy - i.e. base of skull tumours, but not indicated in palliative Rx
List 2 contributors to radiosensitivity of cancer cells compared to normal cells
- Differences in repair capacity (Cancer cells are less able than normal cells to repair ‘sublethal’ radiation damage)*
- Oxygenation (hypoxic cells are relatively radioresistant)
-The number of cells actively dividing (cells in certain phases of the cell cycle are more sensitive than others) -> non-cycling
cells are relatively radioresistant*
-rate of repopulation within the tumour
FS: cancer cells have less ability to repair and more dividing cells
- What are the 2 aims of radical radiotherapy?
- What are the 2 aims of palliative radiotherapy?
- Radical:
-Complete eradication of tumour cells
-Minimize long-term normal tissue damage - Palliative:
-Control of symptoms
-Minimal acute radiation reaction
- When delivering XRT, how is normal tissue damage minimized?
- For curative-intent treatment, how is the schedule adjusted to reduce tumour repopulation? List 2 ways.
- For palliative treatment, how is acute reaction minimized?
- What is the relationship between tumour shrinkage and symptom control?
- Radiation dose is built up with daily treatment over several weeks
- Acceleration - giving treatment over a shorter period of time (but limited by acute reaction)
- Hyperfractionation - higher dose is delivered by increasing number of fractions (multiple per day) but over same time period
- Low dose radiation given over short course
- Symptom control does not require complete eradication of tumour
(i.e. for metastatic bone pain, symptom response seems independent of tumour shrinkage. Mechanism unclear - related to osteoclast activity?)
List the 3 main types of radiation delivery
- External beam treatment (most common)
- Brachytherapy (internal radiation)
- Systemic radioisotopic therapy
List 5 modes of external beam radiotherapy and the anatomical site of their use
***Do we need to know this??
See Table 14.3.1 (energy/source/depth of penetration excluded here - ?relevant):
- Superficial x-rays: surface skin tumours
- Orthovoltage x-rays: surface tumours, superficial bones (ribs, sacrum)
- Electrons: surface tumours, superficial bones, lymph nodes
- Megavoltage x-rays: main radiation for sites other than above
- Gamma rays: all sites except superficial skin
What is the device used to deliver radiotherapy? How does it work?
Linear accelerator
produces high energy X-ray beams (or for superficial lesions, an electron beam)
- How does brachytherapy work?
- When are systemic radioisotopes used? Give 2 cancer examples and their isotopes
- Bracytherapy - use of a radioactive source placed directly onto/within treatment area so radiation is given directly into the tumour
- Systemic radioisotopes - given when specific tissues can be targeted (oral or IV)
- radioiodine - thyroid cancer
- strontium and radium - bone metastases
Brachytherapy:
List 3 ways it can be placed
List 2 isotopes used
Table 14.3.2 (12.3.2)
Intracavitary -> Iridium, cobalt
- Intrauterine
- Intravaginal
- Endo-oesophageal
- Endobronchial
- Endorectal
Interstitial -> Iridium, cobalt, iodine, caesium
- Tongue, floor of mouth
- Buccal mucosa
- Breast
- Anal canal
- Vulva/vagina
Surface (Mould) -> Iridium, Cobalt
- Skin
- Penis
List the 4 steps of radiation treatment planning
- IMMOBILIZATION
- to avoid normal tissue/critical structures - TREATMENT VOLUME LOCALIZATION
- i.e. CT for clear definition of non-superficial lesions - DOSIMETRIC PLANNING
- i.e. single beam vs 2 opposing vs stereotactic - VERIFICATION
List 3 scenarios in which more complex radiation planning may be needed
- Tumour sites close to the spinal cord
- Retreatments close to critical organs
- Treatment of oligometastases (<3 mets) when higher doses may be considered
- What is the underlying mechanism of ACUTE radiation toxicity?
- How does recovery happen?
- How long does recovery take?
- What happens if there is poor healing?
- Loss of surface EPITHELIAL CELLS resulting in skin erythema or desquamation mucositis (i.e. esophagitis, cystitis, GI irritation)
- Repair of the denuded surface (if stem cell population not damaged irreparably)
- Usually within a few days or weeks. May take longer in sites of less efficient skin healing (lower leg, back)
- Rarely, poor healing may lead to radiation necrosis (i.e. secondary to infection or trauma)
List 6 acute side effects of XRT
Table 14.3.3:
- Skin: erythema, desquamation
- CNS: transient demyelination (Lhermitte’s sign)
- Eye: Keratitis
4: Oral cavity: Mucositis
- Pharynx: Dry mouth, taste loss
- Lung: pneumonitis
- Gastrointestinal tract: N/V, anorexia, Diarrhea
- Bladder: Sterile cystitis
FS:
Dermatitis
Mucositis
Pneumonitis
Gastritis
Proctitis
Cystitis
- LATE radiation damage - what is the underlying mechanism?
- How long after treatment can late radiation damage manifest?
- What are the clinical manifestations of this? List 1 minor and 1 major finding.
- How can late radiation damage be avoided during planning? What is 1 unavoidable risk factor?
- Due to VASCULAR damage with pathological changes (endarteritis obliterans –> closure of small blood vessels)
- Rarely seen before 9 months —> ongoing risk for many decades
Minor - skin atrophy, telangiectasia seen on treated skin/mucosal surfaces
Major - fibrosis, necrosis, stricture, fistula
- Every tissue has “tolerance dose” - up to which normal tissue damage NOT expected in “normal population”
Planning = avoid exceeding this dose but deliver effective dose to adjacent target
Some people are genetically predisposed to radiation damage even with conventional dose
List 4 late side effects of XRT
List 4 organs that may be involved
Table 14.3.3
- Skin - atrophy, fibrosis, telangiectasia, necrosis
- CNS - myelitis, necrosis, local edema
- Eye - cataract, entropion or ectropion, dry eye
- Oral cavity/pharynx - mucosal atrophy, telangiectasia/bleeding, dental caries, mandibular necrosis
- Lung - fibrosis
- GI - stricture, telangiectasia, bleeding, perf, malabsorption, chronic enteritis, colitis, proctitis
- Bladder - reduced volume, telangiectasia/bleeding, urethral stricture, ureteric stricture, fistula
FS: fibrosis, fistula, stricture, necrosis
List the 4 management tips of the following radiation side effect:
Skin reaction
- Relieve symptoms, allow to heal.
Mild skin reactions - no active Rx needed, avoid local applications
Desquamation - rare after pall dose XRT. Avoid topical preps, esp with metallic salts (can enhance reaction)
Starch powder to keep skin dry
FS: good source
http://www.bccancer.bc.ca/nursing-site/Documents/Symptom%20Management%20Guidelines/14RadiationDermatitis.pdf
Gentle cleaning - non perfumed soap, don’t rub
Water based lotion
Avoid sun
Avoid irritation products, shaving, etc
List the management of the following radiation side effect:
Nausea from irradiation to abdomen/pelvis
- simple
- complex
- prophylactic
- Simple anti-emetic therapy:
mild: metoclopramide
severe: ondansetron - Non-responsive to anti-emetics:
small dose steroid (i.e. prednisolone 10-30 mg daily) - Prophylactic anti-emetic (ondansetron 8mg) + steroid (dex 8 mg) 30 min prior to XRT to avoid severe symptoms
List 3 management of the following radiation side effect:
Radiation-induced acute diarrhea
- Low-fibre diet
- Loperamide after each loose BM
- Codeine phosphate on 3-4 times daily
List 4 management of the following radiation side effect:
Radiation cystitis
- Alpha blocker such as tamsulosin for severe bladder spasm
- Significant dysuria or strangury - systemic analgesics
- Potassium citrate or cranberry juice (supportive value, no objective evidence)
- Rule out secondary infectio
FS; usual tx of bladder spasm + rule out UTI
List 4 management of the following radiation side effect:
oropharygeal mucositis
- what should be considered if there is severe mucositis?
- what should be considered before radiation of head and neck?
- Maintain high level of oral hygiene (Regular chlorhexidine mouthwashes)
- Prophylactic anti-candidal prep with nystatin suspension or clotrimazole gel
- Local pain relief: soluble ASA or benzydamine mouthwashes
- Avoid smoking, ETOH during treatments (worse symptoms)
- If severe Sx + nutritional impairment, consider enteral feeding
- Formal pretreatment dental assessment (XRT to salivary glands –> mouth dryness –> dental caries; osteoradionecrosis of the jaw)
- List 2 presenting symptoms of radiation induced pneumonitis
- How long after treatment can pneumonitis occur?
- How is it diagnosed on imaging?
- What is the treatment?
- Dry cough and dyspnea
- Can present up to 4 months after treatment (considered acute SE)
- Interstitial pneumonitis - Appears on chest xray as patchy shadowing conforming to geometry of radiation field
- A 2-3 week course of systemic steroids with antibiotics for secondary infection (but continuing symptoms and late radiation fibrosis may ensue)
List 5 indications for radiotherapy in symptom palliation
Table 14.3.4 (12.3.4)
Pain - bone, visceral, neuropathic
local pressure - spinal canal compression, cranial nerve palsies
Obstruction - bronchus, esophagus, SVC, hydrocephalus
Bleeding - hemoptysis, hematuria, vaginal bleeding, rectal bleeding
Malignant fungating wounds
FS: WP = BOS
Wound
Pain
Bleeding
Obstruction
SCC
Re-irradiation of painful bone mets should be offered to a patient in what condition
- pain continues or recurs after good initial tx
List 3 indications for radiotherapy to bone metastases
- Bone pain
- Pathological fracture
- Pressure on nerves
- Which four cancers benefit from combined tx - concurrent chemo and xrt*
- Which 4 cancers benefit from neoadjuvant or adjuvant systemic Rx (before or after radiotherapy)*
- esophagus, cervix, anal canal, lung, head and neck
- breast, SCLC, colorectal, bladder, and lymphoma
- What do meta-analyses show re: benefit of prolonged fractionated course of XRT vs. single fraction of 8 Gy for local metastatic bone pain
- When would bone management with a protracted fractionated course delivering 20-30 Gy over 1-2 weeks be preferred?
- No advantage of prolonged course.
Single fraction - durable pain control at 12 months with 80% response rate - Concern for pathological fracture or nerve compression
How soon after radiation treatment can patients experience improvement in pain?
About 50% of patients will have pain relief within the first 2-4 weeks
Others may experience pain after 6-8 weeks after
Why is it important to document the radiation field margin?
- Overlap of fields can result in overdosage (i.e. to the spine with sequential treatment of multiple spinal mets –> risk of radiation myelitis within 6-9 months of treatment)
- May require re-treatment in future, potential for overlap of fields
What 2 types of radiotherapy can be used for pain that presents DIFFUSELY / affecting multiple sites.
- Wide-field radiotherapy - delivers treatment to an area that may include up to half the body - up to 6 Gy to upper body (dose limited by lungs) or 8Gy to lower half
- Radioisotope therapy
Wide field radiation and radio-isotope therapy for painful bone mets carry what hematologic risk?
bone marrow suppression - need for regular blood transfusion, AND rarely, clinically relevant neutropenia, thrombocytopenia
How does radioisotope therapy work? Give 1 example of its use.
- Ideal isotope delivers radiation dose by release of beta particles within immediate area of uptake. Gamma release also desirable - can image isotope distribution with gamma camera
- Radium-223 (pure alpha-emitting radioisotope) or strontium (beta emitting)
- concentrates at site of osteoblastic reaction
- effective for castrate-resistant met. prostate CA
- improved bone pain, SRE’s, prolonged survival
FS:
- IV radium injected and concentrates in bone Mets (it mimics calcium)
- release alpha particles which damages DNA of cancer cells => cell death
- What are the sequence of events leading to spinal cord compression (3)?
- What are the 2 main sources of cancer spread causing SCC?
- i) Initial events vascular –> venous engorgement and edema
ii) Mechanical compression
iii) Irreversible damage to nervous tissue
- i) Direct encroachement from vertebral body (25% cases)
ii) Remainder are blood-borne extradural and intradural metastasis
What part of the spine is most commonly involved with spinal cord compression?
What are the three most common cancers with spinal cord compression?
List three symptoms that would suggest SCC
Thoracic spine (70%), lumbosacral (20%), 10% (cervical)
breast, lung, prostate (each 20%) then kidney and lymphoma
-myeolma 11%
Pain - progressive, crescendo pattern, radicular, aggravated by lying down, associated with valsalva, or chronic pain that changes character
L’hermitte’s sign
Pain precedes neuro deficits
Neuro deficits - sensory or motor findings, urinary symptoms
List four treatments for SCC
Steroids
Surgical decompression (laminectomy)
Radiation
Chemotherapy - lymphoma, SCLC
Outcomes of spinal cord decompression are dependent on which 3 factors
degree of neurological impairment at diagnosis
promptness of treatment
response to treatment
- patients presenting ambulatory, 79% will remain ambulatory post XRT
- those presenting with paresis, only 42% become ambulant and 20-25% will deteriorate during XRT alone
- What are the outcomes for pain control in SCC with radiotherapy vs laminectomy
- How does histology influence this outcome?
- XRT will achieve pain relief in over 3/4 patients vs laminectomy achieve pain relief in 1/4 of patients
- Myeloma, lymphoma have better outcome, than breast,
than lung, kidney
- What is the expectation for recovery after paraplegia
- What is the ideal XRT treatment schedule for SCC for (a) pall patient (b) has higher PPS/more prognosis
- Recovery not expected after paraplegia established for more than 24 hours (single dose of 8-10 Gy given for pain relief only)
- 2 RCT’s have shown no difference between single 8 Gy fraction vs. 16 Gy in 2 fractions vs. 20 Gy in 5 fractions
(However some patients with good PPS/prognosis will still receive 20-30 Gy in 5-10 fractions)
List three prognostic factors that suggest increased survival after irradiation of brain mets
Table 14.3.5:
Brain first site of relapse
Brain sole site of relapse*
Long disease-free interval prior to brain relapse
Primary site in brain
Performance status *
Age < 60 years*
~~~
- What are 2 indications for decompressive surgery to treat SCC?
- What is the role of post-op radiotherapy?
- i) Extensive vertebral collapse with intrusion to spinal canal (spinal instability)
ii) Good PPS + prognosis > 3 months + single level of compression
- Unclear - may help with pain
What mechanism of cancer spread makes solitary brain mets uncommon?
What are the two most common cancers to spread to brain?
Cancer spreads via blood stream; given there is blood brain barrier -> solitary brain mets are unusual
lung and breast are most common
List two types of radiotherapy that can be used for brain mets
WBRT
RADIOSURGERY = Localized + high dose radiotherapy -> uses either dedicated multisource cobalt unit (gamma knife) or stereotactic high energy Xray unit
List three cancers that would make you choose chemo > radiation or surgery for initial management
lymphoma, SCLC, germ cell tumor
List three (cancer specific) prognostic factors that suggest decreased survival with brain mets
> 3 mets
multiple lobes involved
meningeal disease
Other than tumor - list 3 causes of SVC obstruction.
What is the most common type of cancer to cause SVC obstruction?
aortic aneurysm, chronic mediastinitis, trauma, or thrombosis following central venous catheterization
Lung - bronchial carcinoma
What is the most common location of mets to the eye?
What are the two most common cancers that cause this type of met?
A patient is diagnosed incidentally on PET scan. Is this worth treating prophylactically?
Choroid
Breast and lung
Yes treat prophylactically to preserve vision
List 5 symptoms of SVC syndrome
headaches * somnolence* dizziness rarely convulsions result from cerebral hypertension dyspnea* cough* Dysphagia hoarseness engorgement of arm and neck veins with visible dilatation of superficial skin veins* cyanosis* facial oedema*
List four treatments for SVCO due to tumor
bronchoscopy with stenting Insertion of SVC stent * chemo* radiation * steroids*
List three measures to manage dysphagia due to tumor compression (beside radiotherapy)
analgesics and anticholingergic drugs to reduce secretions
consideration of nutrition by a percutaneous gastrostomy
FS: ? SLP referral
Fungating malignant wounds are seen most commonly due to what malignancy?
Lymph nodes in what two regions can cause fungating lesions?
breast cancer > invading into chest wall
metastatic LNs in the neck or groin > fungating wound
What 2 delivery types of rads can be used for hemoptysis control?
Is there any evidence to support prophylactic treatment of lung tumors to prevent hemoptysis?
(1) external beam treatment
(2) endobronchial brachytherapy
No evidence but some suggest treating tumors >10cm diameter as these have high risk of bleed
List five conditions that can cause hematuria in a cancer patient
a lesion in the bladder (primary)
local infiltration of an advanced rectal or uterine carcinoma, advanced renal cell carcinoma or urethral infiltration by carcinoma of the prostate
infective cystitis
chemical cystitis associated with certain chemotherapy agents such as cyclophosphamide or ifosfamide
bladder telangiectasia (following high-dose radiotherapy to the bladder (or adjacent pelvic organs
thrombocytopenia or a blood coagulation defect
FS:
Trauma
Infection
Neoplasm
Stone
Systemic (thrombocytopenia)
What is the main symptomatic side effect from bladder radiation
diarrhea
Radiotherapy for prevention of fungating wounds is best achieved when skin is in what state
intact - before fungation has occurred
How can radiotherapy help with tx of hypercalcemia and paraneoplastic phenomena?
local irradiation may result in improvement and resolution of the paraneoplastic symptoms as the tumour regresses - locate source of chemical agent and treat with radiotherapy
Splenomegally is associated with hematologic malignancies.
- List two symptoms of a bulky spleen.
- List two symptoms of hypersplenism.
- List 1 major complication if XRT is used to tx splenomegally - prophylactic tx?
local bulk (causing pain and discomfort) hypersplenism (causing consumption of red cells and platelets)
high doses of xrt may precipitate
(1) pancytopenia
(2) Tumor lysis syndrome
the spleen from lymphoma or leukemia often sensitive to XRT - give allopurinol to prevent tumor lysis syndrome (decrease uric acid)
What is the preferred treatment for splenomegally in hematologic disease?
Surgical removal of the spleen is the preferred management
Radiation in advanced disease or in patients with poor performance status
What is a typical dose of XRT given for pain due to bony mets and why
single fraction of 8Gy because no increased dose response above that amount
List three interventions to urinary tract obstruction that might be considered prior to radiotherapy
nephrostomy tube
ureteric stent
transurethral resection of an intrinsic urethral tumour (TURP)
