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