Accelerated Hypofractionated High Dose Rate (HDR) Brachytherapy for Skin Cancer Emilia Timotin

71st Annual General Conference of the
Canadian Association of Medical Radiation Technologists
Accelerated Hypofractionated
High Dose Rate (HDR)
Brachytherapy for Skin Cancer
Emilia Timotin
BSc, MRT(T)
May 22-25, St. John’s, Newfoundland and Labrador
Hosted by the Newfoundland and Labrador Association of Medical Radiation Technologists
71st Annual General Conference of the
Canadian Association of Medical Radiation Technologists
DISCLOSURE
May 22-25, St. John’s, Newfoundland and Labrador
Hosted by the Newfoundland and Labrador Association of Medical Radiation Technologists
LEARNING OBJECTIVES
Become familiar with:
-What is high dose rate brachytherapy?
-Anatomical location of skin cancer most suitable for
brachytherapy
-Brachytherapy procedure for skin cancer patients
including custom-made mould applicators
-Formulating why brachytherapy is an ideal modality
for some skin cancer patients
RADIATION THERAPISTS
NURSES and NURSES AIDE
MEDICAL PHYSICIST
SKIN CANCERS
EPIDEMIOLOGY
NON MELANOMA SKIN CANCER
Basal cell carcinoma (80%) (BCC)
Squamous cell carcinoma (20%)(SCC)
MELANOMA
PREMALIGNANT SKIN LESIONS
Actinic keratoses (malignant
transformation ~15 %)
Bowen ́s disease (invasive ~20%)
Keratoacanthoma (visible as SCC in 6%)
SKIN CANCERS
TREATMENTS OPTIONS
Surgery
Photodynamic
Therapy
Brachytherapy
Topical agents
External beam
radiotherapy
Cryotherapy
BRACHYTHERAPY
Source used
• Brachytherapy is Greek for:
• Brachy = short distance
• Therapy = treatment
• Remote Afterloading is:
• Cancer treatment with radioactive sources
controlled from a distance
BRACHYTHERAPY
Brachytherapy is a form of
radiotherapy. It involves the
precise placement of
radiation sources near the
site of the cancer cells.
Compared to
conventional external
beam radiotherapy
(EBRT), the technique
minimizes damage to
surrounding tissues.
BRACHYTHERAPY FOR SKIN CANCER
A BIT OF HYSTORY
in the early 1900’s
Discovery of radium
Wax molds with radium or
radon seeds/needles
Ashby et al. in 1989
- 642 patients with skin cancer
- local control - 96.8%
- long-term complication rate less than 1%.
Placed manually in
direct contact with
tumours using
surface applicators
BRACHYTHERAPY FOR SKIN CANCER
PATIENT CANDIDATES treatment areas:
• Head & Neck (nose, lips, cheek)
• Scalp
• Breast & Chest wall
• Extremities
• Regular and Irregular (oblique) surfaces
• Inoperable tumors
• Relapses after surgery
BRACHYTHERAPY FOR SKIN CANCER
WHY brachytherapy?
Cancer
Brachytherapy
Alternative:
Surgery
End Result
BRACHYTHERAPY FOR SKIN CANCER
JCC EXPERIENCE
9 patients treated with
Accelerated
Hypofractionated HDR
Brachytherapy since 2007
The lesions represented
various types of histology.
HISTOLOGY
# OF
PATIENTS
Basal Cell (BCC)
1
Squamous Cell (SCC)
3
Angiosarcoma (ASC)
3
Nodular Melanoma
(NMC)
1
Leiomyosarcoma (LMC)
1
BRACHYTHERAPY FOR SKIN CANCER
LOOKING FOR:
• local control
• cosmesis
• patient comfort (treatment and time)
There are three main stages to the brachytherapy
procedure:
a) Planning
b) Treatment delivery
c) Post-procedure monitoring.
BRACHYTHERAPY FOR SKIN CANCER
PLANNING
Clinical Mark-up
• PTV outlined with radiopaque marker
Mask Construction
• Solid sheet of aquaplast used to create mask
• Placed in hot water bath
• Moulded to patient
• Aquaplast sheets or wax applied on top of
mask to hold catheters
BRACHYTHERAPY FOR SKIN CANCER
CT Simulation
• Patient scanned with
mask and mould on
• 2.5mm slice thickness
• Marker inserted into
catheters
BRACHYTHERAPY FOR SKIN CANCER
• Dose prescribed to a
depth determined by the
ISODOSE DISTRIBUTION
radiation oncologist
• ~1cm catheter spacing
BRACHYTHERAPY FOR SKIN CANCER
Isodose distribution matches the shape and
undulations of the surface that is being
treated, to produce conformal radiotherapy
BRACHYTHERAPY FOR SKIN CANCER
TREATMENT DELIVERY
• Before treatment, a test run
without the patient is done
• Patient positioned
• Shielding and mask
placement
• Channels labeled and checked
• Pre-treatment QA
• Catheter placement check
BRACHYTHERAPY FOR SKIN CANCER
A
C
B
D
E
BRACHYTHERAPY FOR SKIN CANCER
LESION
SIZE
(cm)
14 x 5
12 x 14
8 x 14
3x7
8 x 4.7
5x6
2x2
1 x 1 (3)
1x1
TREATED TYPE OF
# OF
AREA
CANCER CATHETER
(cm)
S
19 x 6
ASC
7
9.5 x 14
SCC
15
9.5 x 14
SCC
9
4.5 x 8
BCC
9
14 x 18
NMC
18
9x9
SCC
10
3x5
LMC
4
4x3
ASC
5
4x4
ASC
4
The lesion sizes
were
anatomically
irregular and
large, with
challenging
curvature of the
surface area.
BRACHYTHERAPY FOR SKIN CANCER
DOSE FRACTIONATION
•
•
•
•
•
Standard dose prescription 30Gy
10 fractions
3 Gy per fraction (hypofractionated regimen)
2 fractions/day 6 hours apart (accelerated regimen)
Out patients
BRACHYTHERAPY FOR SKIN CANCER
Patient monitored every day
for side effects
– erythema
– pruritus
Patient experience:
– desquamation
• Treatment time - 3 to 8 minutes in
– scabbing
each session.
• Moulds - tolerable/very ease to use.
• Patients felt comfortable during
treatment.
• No need for treatment interruption.
BRACHYTHERAPY FOR SKIN CANCER
LESION LOCATION
# OF LESION
RESPONSE
Left Frontal Parietal Skull
1
CR
Left Shin
Vertex Right Scalp
Left Parietal, Left Temporal,
Left Frontal
Scalp
Top of Scalp
Upper Lip
Right Scalp
Right Dorsal Forearm
1
2
1, 1, 2
PR
CR
Patient out of
region
PR
CR
CR
CR
CR
1
1 recurrence
1
1
1
BRACHYTHERAPY FOR SKIN CANCER
ADVANTAGES
Applicable in all types of basal cell and squamous cell
carcinoma, without restriction by site, dimension, clinical
or histological type, or the patient’s clinical situation
• Higher local control, due to higher dose to target volume
• Less dose to surrounding tissue due to sharp fall-off of radiation
dose
• Higher treatment dose delivered to the center of the tumor which is
more radiation resistant
• More conformal treatment due to stepping source technique
•Short course of treatment compared to other types of
radiation treatment (1 week)
•Preservation of organ structure and function – Excellent
cosmesis
•Fewer side effects
•Accuracy and precision of tumor specific radiation dose
delivery
•Minimizes areas of radiation overdose (hot spots) or
underdose (cold spots)
•Organ motion (target movement) is not a problem for
HDR as it is with external beam
•Shorter recovery time compared to surgery
BRACHYTHERAPY FOR SKIN CANCER
DISADVANTAGES
• Only local treatment
• Special skills and training are needed
• Licensing and credentialing needed
• Complete coverage of target volume is essential
• More susceptible to dosimetry errors in delivery of
radiation
BRACHYTHERAPY FOR SKIN CANCER
CONCLUSIONS
Accelerated Hypofractionated HDR Brachytherapy
- safe and simple alternative to surgical or external
radiation treatment for superficial skin carcinomas
for patients with difficult clinical conditions or varying
anatomical curvature of the area.
- non-invasive, painless and very convenient for patients.
- given on an outpatient basis
- the times are typically short, between 10-20 minutes,
- treatment is achieved over 5 days with good tumour
response and cosmesis.
Acknowledgments
The author is grateful to DR. RANJAN SUR, TOM FARRELL,
ROB HUNTER and MARCIA SMOKE for their contribution
to the presentation.
An acknowledgment goes to the radiation therapists IRENE
PAPUGA, FIONA ELLIS, MARIA LEON, TRACY HARRIS,
ROB STICKLES for their collaboration and skill during the
preparation and execution of the treatment; the nursing staff
MICHELLE BURNSIDE, JACKIE WINKS, PATTY
DEMEIS for providing necessary aftercare, and also our
experienced physicists MARTIN SHIM and JOE HAYWARD.
THANK - YOU