Transcript Radiotherapy and More…

Radiotherapy and More…
Linda Bedford, Macmillan Lead AHP, Peninsula Cancer Network
Sally Donaghey, Macmillan AHP Lead, Anglia Cancer Network
Radiotherapy
Radiotherapy is designed to direct a lethal dose
of radiation directly to cancer cells in tumours,
while minimizing exposure to the healthy cells
that surround them
Radiation beam passes through all the cells in
its path
Linacs direct the beam to the tumour in short
bursts from many different angles
– healthy cells actually receive less radiation
– cancerous target at the centre receives a significantly
larger dose.
Physics
Atomic structure
More Physics
X-Ray production:
– When atoms are
struck by high energy
electrons
– Deceleration leads to
“braking energy” –
bremmstrahling xrays
– Interaction with
orbiting electrons
causing movement
within orbit and/or
ejection, leads to
“characteristic xrays”
www.ucl.ac.uk
Radiotherapy – what happens?
Radiotherapy
Indirect damage – Free radicals
Direct damage - Ionisation
DNA damage
(replication, function)
Cell death
(therapeutic and side effects)
Cell modification
(Potentially harmful)
A Linear Accelerator
A Bunker
Patient Immobilisation Devices
Portal Imaging
MLC’s
Multileaf collimators
IMRT
– Intensity Modulated Radiotherapy
IGRT
– Image Guided Radiotherapy
Gating
Patient respiration during radiotherapy can
cause significant motion of the tumour
Simple 2 Field Technique
27 segment Forward planned IMRT
Dose shaped around critical organ at
risk
Sterotactic Radiosurgery
TBI
Total Body Irradiation
Brachytherapy
For the women
And for the men
Cyber Knife
The Future
Proton therapy
Works by aiming energetic particles (in
this case, protons accelerated with a
particle accelerator) onto the target
tumour.
Effects on Tissues
Effects are indiscriminate
– Normal
– Malignant cells
Tissue tolerance – dose
limitation
Therapeutic window
–
–
–
–
–
Radiosensitivity
Sensitive tissue
Bigger window
Lower effective dose
Fewer side effects
www.dkfz.de
Dose and Fractionation
Radiation doses are measured in the unit Gray (Gy), just like flour is
measured in kg
Doses delivered in “fractions”
Safe delivery of higher total dose
Smaller areas can be treated to higher doses
Exploitation of cell cycle
Dose (generally) proportionate to damage
Low dose potential for sub lethal damage
Cell repair
Serial and parallel organs
Biologically effective doses
Examples of dose:
– 70Gy in 35 # - 2 Gy per fraction.
– 8Gy single #
Side Effects
Acute side effects:
Rapid cell division/high
mitotic activity
Sudden, short-term
effects
Commence during/end of
treatment (2-3 weeks)
Repair 4-12 weeks post
tx
Genetics
Chronic side effects:
Develop months/years
after treatment
Longer term or
permanent changes
Expression of damage
not evident immediately
– Eg nervous tissue – v
slow mitotic division so
damage presents with
later effects.
Carcinogenesis
RT causes cancer
Hiroshima and Chernobyl
Generally within organ/site previously
irradiated
Latent period of 5-30 years depending on
studies
Risk factor of younger age at initial tx
HD
leukaemia and breast Ca
Brain tumours
PCI/CNS tx
Leukaemia
Ankylosing spondylitis
Teratogenicity
–
–
–
–
Radiation during pregnancy
To be avoided unless clinically indicated
Highest risk in first trimester
Patient choice regarding tx
Radiosensitive Tissues
Highly Sensitive:
–
–
–
–
–
Skin
Lining of GI tract
Oro-pharynx
Haemopoietic tissues – bone marrow
Reproductive cells
Intermediate Sensitivity:
–
–
–
–
–
Liver
Kidney
Lung
Nervous tissue
Eye
Low Sensitivity
– Bone
– Muscle
– Connective tissue
Skin
Skin
–
–
–
–
Inevitable
Skin folds
Moist areas
Thin skin areas
Effects:
–
–
–
–
–
–
–
Erythema
Dry desquamation
Moist desquamation
Hair loss
Pigmentation
Fibrosis
Telangiectasia
Skin Management
Conflicting evidence (please see October 2011 report
from Scor)
–
–
–
–
–
–
–
–
–
–
–
Advice
Loose cotton clothing
Don’t scrub
Unperfumed soaps
Aqueous cream
No wet shaving
Chlorine
Hydrocortisone
Hydrogel
Hydrocolloid
Silicone dressings
Oro-Pharynx
Oro-pharynx
–
–
–
Epithelial turnover and thinness of skin
in area
Can interrupt tx
Exacerbate surgical/functional
difficulties
Effects:
–
–
–
–
–
–
–
–
–
–
Mucositis
Dysgeusia
Xerostomia
Dysphagia
Pain
Oedema
Mucosal fibrosis and atrophy
Dental caries
Osteradionecrosis – 60 Gy TD5/5
Susceptibility to ulceration
www.caphasol.ca
Oro-Pharynx Management
Advice
Support
Dietetics
–
–
–
–
–
–
Liquidise food
Small portions frequently
Sips of water
Supplements
Dispersible analgesia/anaesthesia before eating
Avoid spicy/sharp/v hot/v cold food
Speech therapy
Physiotherapy
Oral hygiene
Loose clothing
Gastro-intestinal
Gastrointestinal
– Rectum can be OAR for other
pelvic treatments
– Consider whole length of tract
Effects
–
–
–
–
–
Diarrhoea
Proctitis
Rectal bleeding
Nausea
Vomiting
– Enteritis/granulation leading to
stricture and obstruction
– Permanent change in bowel habit
– Faecal incontinence
– Fistulae
medrevise/.co.uk
Gastro-intestinal Management
Conformal RT/IMRT improving side effect profile
Advice
Anti-emetics
Anti-diarrhoeals
Creams
Corticosteroids
Dietary advice
Clothing
Hydration
Breast
Skin
Fibrosis
Shinkage
Hardening of tissue
Lymphoedema
Rib fractures – 1%
Lung fibrosis/pneumonitis
– maximum lung volume
Cardiac toxicity –
particularly 60+. Max
heart volume
www.wales.gov.uk
Fatigue
Common, underestimated in effect and
debilitating
High incidence
Ltd management options
– NICE guidance = info
and exercise advice
Patterns of fatigue
– Cumulative ?increase with dose/tx
– Persistence post tx 412 wks+
Management:
Its normal
Energy conservation
Fluids and diet
Delegate!
Rest when needed
Gentle exercise may help
to increase energy levels
Organise and plan ahead
Thank you
Any Questions?