AAMD 44th Annual MeetingJune 16 – 20, 2019
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BRACHYTHERAPY BASICS
Mitchell Kamrava, MD
Residency Program Director
Director Brachytherapy Services
Associate Professor
Department of Radiation Oncology
Cedars Sinai Medical Center
Samuel Oschin Comprehensive Cancer InstituteCedars‐Sinai Medical Center
DISCLOSURES
• None
Samuel Oschin Comprehensive Cancer InstituteCedars‐Sinai Medical Center
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OUTLINE
• Intro to brachytherapy basics
• Breast brachy
• Gynecologic brachy
• Prostate brachy
BRACHYTHERAPY:TREATING FROM INSIDE OUT
Brachytherapy provides
• Radiation that is close to or within the tumor
• High dose to target volume
• Sharp dose fall-off
External beam therapy works from the outside → in
Brachytherapy works from the inside → out
Edited image and rekeyed info and lines
Bladder Prostate
Radioactive seeds
Rectum
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THE EVOLUTION OF BRACHYTHERAPY
1. Gupta VK. J Med Phys. 1995;20(2):31-35; 2. Nag S. American Brachytherapy Society; 3. Aronowitz JN, et al. Brachytherapy. 2007;6:293-297; 4. Blasko JC, et al. J Urol. 1995;154:1096-1099; 5. Grimm P, et al. BJU Int. 2012;109(suppl 1):22-29; 6. Thariat J, et al. Nat Rev Clin. Oncol.2013;10:52-60; 7. Viani GA, et al. J Exp Clin Cancer Res. 2009;28:47; 8. Lukens JN, et al. Semin Oncol. 2014;41:831-847.
1901Brachytherapy first used for lupus and malignancies1,2
1903Brachytherapy first used for gynecologic cancers3
1917Techniques developed for prostate cancer4
1920sBrachytherapy widely used to treat accessible tumors with radium6
1950s-1960sNew sources, techniques, and equipment reduced patient and physician exposure to radiation leading to a renaissance for brachytherapy1
OngoingAccepted as an important treatment option with strong supporting data for numerous cancers5,7,8
1970sBrachytherapy established as safe and standard-of-care for gynecologic cancers7
BROAD CLINICAL UTILITY OF BRACHY
Bronchus, LungBreast
Bladder, Rectum
Cervix, Uterus, Endometrium,
Vagina Prostate
Gall bladder, Bile duct
Esophagus
Head & NeckTongue, Nasopharynx
Skin, surface
Female Male
Most common uses
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SPECIALIZED APPLICATORS AND AFTERLOADER
MATCHED TO TREATMENT NEEDSGynecologic Breast
Skin
Lung Prostate
Afterloader
• Applicators are placed adjacent to the tumor
• Additional needles can provide coverage outside of target area
• Useful for following body sites
• Gynecologic – cervical, endometrial, vaginal
• Rectum
• Nasopharynx
• Breast (post procedure)
INTRACAVITARY BRACHYTHERAPY APPLICATIONS
Tandem
Rectum
Bladder
Cervical Cancer
Applicator
Uterus
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INTERSTITIAL BRACHYTHERAPY APPLICATIONS
• Catheters are placed into the lesion and adjacent tissue
• Useful for following body sites
• Prostate
• Breast
• Head and neck
• Bladder
• Brain Template to aid accurate placement of the needles delivering the seeds
Needle, delivering seeds into prostate
Ultrasound probe in
rectum for needle
guidance
Catheter in urethra
INTRALUMINAL BRACHYTHERAPY APPLICATIONS
• Applicators are placed adjacent to the tumor
• Useful for following body sites
• Lung
• Esophagus
• Biliary
Radiation Zone
Cancer
Radiation Wires
Endobronchial Radiation
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SURFACE BRACHYTHERAPY APPLICATIONS
• Applicators are placed on the skin
• Useful for treatment of keloids and some types of skin cancer
BRACHYTHERAPY WORKFLOW
• Applicator placement
• Simulation
• Catheter reconstruction
• Target/OAR contouring
• Planning
• Treatment
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TEMPLATE MAPPING AND APPLICATOR DIGITIZATION
CATHETER RECONSTRUCTION
Multiple ChannelsSingle Channel
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IMAGE TECHNIQUES AND FUSION
• CT or MR based planning?
• Image fusion can be difficult
• Applicator/Catheter digitization can be tricky
• Plan can be created on CT or MR when using TG43 calculations
TARGET/OAR/CATHETER 3D RECONSTRUCTION
Images courtesy of UCSFTarget and OAR reconstruction Inclusion of catheters and possible dwell positions
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INVERSE PLANNING SIMULATED ANNEALING
Images courtesy of UCSF
PLAN OPTIMIZATION AND REVIEW
• Scripting
• Plan Quality Report
• OAR constraints
• External Beam Radiation considerations (EQD2)
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HIGH DOSE RATE (HDR) BRACHYTHERAPY –REMOTE AFTERLOADING
Iridium 192
The radiation strength is proportional to dwell time
BREAST BRACHYTHERAPY
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1-2 weeks
2 d - 1 week 2 d - 1 week
APBI RATIONALE
• Oncologic• Majority of failures are true recurrences (around where tumor started)
• Not clear that treating the whole breast reduces elsewhere failures
• Convenience • Treatment can be completed within 1 week
• Toxicity• Improved breast cosmesis• Decreased organs at risk dose (heart/lung)
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WHO IS A CANDIDATE?
WHOLE BREAST VS APBI (CAVITY + MARGIN)
SAVI Contura T+B IORT EBRT
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APBI TECHNIQUES
• Interstitial tube and button
• treatment 2 times per day for 8-10 treatments
• some early data to support just 3 treatments
• Single entry catheter devices
• treatment 2 times per day for 8-10 treatments
• some early data to support just 3 treatments
• External beam radiation
• treatment 2 times per day for 10 treatments or daily for 10 treatments
• Treatment 1 time per day for 5 treatments
INTERSTITIAL BREAST
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3D Dosimetry Distribution
SINGLE-ENTRY CATHETER DEVICES
Mammosite MammositeML Contura SAVI
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EXAMPLE OF SINGLE ENTRY CATHETER
B39 CONTOURING GUIDELINES
Brachytherapy EBRT
IS – 1.5 cm expansion on cavity
Balloon – 1.0 cm expansion on cavity
EBRT –1.5 cm CTV expansion and 1.0 cm PTV expansion
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SAVI DIAGRAM
PRESCRIPTION
• Brachy
• 3.4 Gy x 10
• 4 Gy x 8
• 7.0-7.5 Gy x 3 (early data)
• EBRT
• 3.85 Gy x 10
• 4 Gy x 10
• 6 Gy x 5
• IORT
• Xoft 20 Gy x 1 to the balloon surface
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DOSE CONSTRAINTS FOR APBI
Shah C et al. Journal Contemporary Brachy. 2016.
BREAST PQRTARGET: D90, V150, V200
OARS: SKIN, CHEST WALL, LUNG
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INTRA-OPERATIVE RADIATION THERAPY
• 1 treatment
• In the operating room
• While you are asleep
• In theory you wake up “done” with radiation
• 3D
• IMRT
• SBRT
• IORT
• Brachy
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EXTERNAL BEAM
Unacceptable Cosmesis in a Protocol Investigating Intensity-Modulated Radiotherapy With Active Breathing Control for Accelerated
Partial-Breast Irradiation
Reshma Jagsi, M.D., D.Phil., Merav A. Ben-David, M.D., Jean M. Moran, Ph.D., Robin B. Marsh, C.M.D., Kent A. Griffith, M.P.H., M.S., James A. Hayman, M.D., M.B.A. and Lori J. Pierce, M.D.
International Journal of Radiation Oncology * Biology * PhysicsVolume 76, Issue 1, Pages 71-78 (January 2010)
DOI: 10.1016/j.ijrobp.2009.01.041
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Visible impairment in cosmesis observed in 3 patients deemed to have unacceptable cosmesis after treatment.
Distribution of the proportion of the breast reference volume in each
case receiving 50% of prescribed dose (V50), by cosmetic outcome
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Whole breast V5 <70%, V50 <40%, V80 <25‐30%, V100 <15‐18%
EBRT APBI
• Can be done safely now with increased attention to spill dose to rest of breast
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GYNECOLOGIC BRACHYTHERAPY
CERVICAL CANCER ~12,000 NEW CASES &
4,000 DEATHS PER YEAR
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TREATMENT OVERVIEW
STANDARD OF CARE (SOC): EBRT + CHEMO + BRACHY
EBRT 5 weeksMon-Fri
20 min daily
Weekly Cisplatin40 mg/m2
5-6 cycles
Brachy4 treatments2 per week
Complete all treatment within 8 weeks
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ARE WOMEN RECEIVING SOC: EBRT + CHEMO + BRACHY?
Robin T et al. Gyn Onc. 2016.
NCDB analysis
15,200 pts
2004-2012
Only 44% received SOC
Improved OS w/ SOC
REDUCTION IN OS WITHOUT THE USE OF BRACHYTHERAPY
Gill B et al. IJROBP. 2014.
INC IN USE OF IMRT/SBRT BOOST DEC IN OVERALL SURVIVAL
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WHY IS BRACHYTHERAPY SO IMPORTANT?LOCATION, LOCATION , LOCATION
• Inside out approach with brachy allows:
• Higher dose to the tumor
• Less dose to the bladder, rectum/sigmoid, and small bowel
BLADDER
RECTUM
TUMOR
MOVING FROM 2D FLUOROSCOPY TO 3D CT/MRI BASED PLANNING
2D
3DCT
3DMRI
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2D PLANNING
Where is the tumor?
Where is the rectum/sigmoid/bladder?
PROBLEM WITH POINT BASED RX
TUMOR UNDER VS OVER COVERAGE
Point A
POINTS CAN UNDERESTIMATE DOSE TO BLADDER AND RECTUM
100% isodose
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NATIONAL TREND TOWARDS VOLUME BASED TREATMENTS
STANDARDIZING VOLUME BASED DEFINITIONS
White – Gross disease (GTV)
Yellow – High Risk Target (HR-CTV)
Orange –Intermediate Risk Target (IR-CTV)
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Slide adapted from Richard Potter
VOLUME VS POINT BASED PRESCRIPTION
HR-CTV
BLADDER
RECTUM
YELLOW LINE –100% of dose
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LIMITATIONS OF STANDARD 3 CHANNEL APPLICATORS
3 channels adequate
Red – tumor Orange – 100% radiation dose
3 channels NOT adequate Coverage adequate with more channels
APPLICATORS THAT ALLOW NEEDLES
Vienna UtrechtSyed/MUPIT
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EXAMPLE OF HOW EXTRA NEEDLES IMPROVE TUMOR COVERAGE
CERVICAL CANCER PLANNING GOALS
• HR-CTV 80-85 Gy (D90 > 85 Gy)
• Most commonly after 45 Gy, 6 Gy x 5 or 7 Gy x 4
• Rectum D2cc < 65 Gy (ideal), < 75 Gy (max)
• Bladder D2cc < 80 Gy (ideal), < 90 Gy (max)
• Sigmoid/Bowel D2cc < 70 Gy (ideal)
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VAGINAL CYLINDERS
Most common indication: Post-op Endometrial
Slide courtesy of Manjeet Chadha
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Slide courtesy of Manjeet Chadha
Brachytherapy. 2015.
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PROSTATE BRACHYTHERAPY
Modern Radiation Therapy
Brachytherapy
Low Dose RatePermanent Seeds
High Dose RateVirtual Seeds
External Beam
9 weeksStandard Fractionation
4-5 weeksHypofractionation
1.5 weeksSBRT
TREATMENT OPTIONS
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HIGHER DOSES OF RADIATION TO THE PROSTATE IMPROVE CHANCES OF PSA
CONTROL
Meier R. Front Oncol. 2015.
?
Samuel Oschin Comprehensive Cancer InstituteCedars‐Sinai Medical Center
HOW HIGH DO WE NEED TO GO?
BED 200?
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HOW CAN YOU GET TO A BED
OF 200?
SBRT
LOCATION, LOCATION, LOCATION
• Brachy provides a solution to safely dose escalate while limiting dose to OARs
• How high can we safely go?
• How high do we need to go?
Samuel Oschin Comprehensive Cancer InstituteCedars‐Sinai Medical Center
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HDR PROSTATE PRESCRIPTION
• Monotherapy (Brachy alone,13.5 Gy x 2)
• Low
• Favorable intermediate risk
• Combination (Brachy+EBRT, 15 Gy x 1 + 45 Gy)
• Unfavorable intermediate risk
• High risk
• Salvage (local failure after prior EBRT)
• 11 Gy x 2
PQR FOR PROSTATE HDR
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LOGISTICS OF BRACHYTHERAPY
• Done in the operating room
• Spinal/Sedation vs General
• ~1 hour
• LDR – all seeds placed in OR
• HDR – treatment given later that day, second treatment next day/week (for monotherapy)
TRUS GUIDED PLACEMENT OF CATHETERS
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HDR BRACHYTHERAPY ULTRASOUND VS CT BASED PLANNING
Ultrasound planning – 2 implants, 1-2 weeks apartTreatment done when you wake up
CT based planning – 2 implants, 1-2 weeks apart vs 1 implant w/ overnight stay and treat next day
Treatment not done when you wake up
HDR Brachytherapy
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CONCLUSIONS
• Brachytherapy is a versatile tool that can be helpful in many disease sites
• It’s most commonly used in breast, gyn, prostate, and skin cancers
• It provides conformal dose to targets while limiting dose to surrounding OARs
• Safe/effective planning requires teamwork between MD, physicist, dosimetrist and therapist
• Brachytherapy is fun “team sport”!!
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