The ART of sparing HEART Dr. Tabassum Wadasadawala Assistant Professor, Radiation Oncology, TMC,...
-
Upload
elijah-stafford -
Category
Documents
-
view
218 -
download
1
Transcript of The ART of sparing HEART Dr. Tabassum Wadasadawala Assistant Professor, Radiation Oncology, TMC,...
The ART of sparing HEART
Dr. Tabassum WadasadawalaAssistant Professor, Radiation
Oncology, TMC, ACTREC
Cardiac sparing techniques
• Use of appropriate technique– 3DCRT– IMRT/IGRT– Protons
• Increasing distance between heart and chest wall– Respiratory gating– Prone position
• Cardiac gating• Reducing Target volume
– Accelerated Partial Breast Irradiation (APBI)– Avoiding boost in select cases
Simple means: 3DCRT on LA/Co
• Benefits majority of patients• 3DCRT plans employing simple heart blocks must be
practiced if PTV coverage not compromised
IMRT/IGRT• Dosimetric advantage
– RNI and in patients with significant heart volume within RT fields
• Various techniques – Selection of appropriate technique depending up on the target volume
• Combining with other techniques– Further reduction in cardiac dose in conjunction with prone or breath
hold
• Image guided radiotherapy– Potential for OAR sparing, dose escalation and adaptive RT
• Extensively investigated – Post BCT and MRM with/without RNI and SIB– Impact on acute and late skin toxicity known – Lack of long term cardiac safety and second cancer data
Randomized trial of Helical Tomo vs Tangents
Van Parijs et al Radiat Oncol 2012 7:80Versmessen et al. BMC Cancer 2012
2 year toxicity grade ≥1 2D RT (N=32) HT (N=37) p value
Skin 60% 30% 0.056
Heart (LVEF) 4.8% 4.6% 0.744
Lung (FEV1) 20.8% 14.8% 0.422
Lung (DLCO) 29.2% 7.4% 0.047
TomoBreast trial (N=123, results reported on 69)
Control Arm: 50Gy/25#+16Gy/8# sequential boost
Experimental Arm: 42Gy/15# with SIB 51Gy/15# with HT
Primary endpoint: reduction of cardiac & pulmonary toxicity
Quality of life also better in HT arm
Breast/Chest wall with Boost (at least on one side)
Tangents FIF-IMRT HT TD-3DCRT TD-IMRT
Total lung
MLD
V40
V30
V20
V10
V5
9.76 (1.26)
7.73 (1.22)
9.53 (1.22)
12.36 (2.06)
24.60 (5.80)
44.15 (7.97)
9.34 (1.34)
8.94 (2.19)
10.98 (2.56)
13.32 (2.89)
22.25 (4.47)
38.48 (6.74)
7.24 (0.91)
1.59 (0.88)
4.37 (1.29)
8.38 (1.70)
18.02 (3.51)
36.00 (5.03)
8.07 (0.56)
6.43 (1.26)
8.07 (1.31)
10.05 (1.30)
15.97 (1.58)
15.97 (1.58)
7.36 (0.96)
5.17 (2.12)
6.80 (2.26)
8.67 (2.29)
14.40 (2.19)
33.91 (4.13)
Heart
Mean
V5
6.07 (1.87)
30.51 (6.35)
4.83 (3.17)
14.25 (8.78)
4.56 (1.07)
20.33 (6.57)
5.06 (2.39)
16.76 (7.17)
4.70 (2.67)
12.82 (6.66)
Tomotherapy for bilateral breast cancer
HT is both pulmonary and cardiac sparing for bilateral irradiation of breast/chest wall
with SIB: need to validate the results in homogenous cohort
T Wadasadawala, Accepted in BJR
Proton therapy
• Definite radiobiological and dosimetric advantage
• Drawbacks:– Limited clinical
experience– High cost– Set up uncertainties– Lack of skin sparing– Respiratory motion
FB DIBH
Koremann et al RO 2005
HEART LAD
Moderately deep breath hold is the key to achieving greatest cardiac sparing
Respiratory gated radiotherapy
Techniques of breath hold monitoring
VARIAN RPM ABC DEVICE
EPID AlignRT CBCT
CINE MODE
Treatment parameter Value
No of BH per field 2.5
Median duration of BH 22 s (10-26)
Median treatment time 18.2 min (13-32)
Improvement in cardiac dose 90%
Unable to do BH 1-14%
Respiratory gated radiotherapy
• Inability to maintain an airtight seal with the mouthpiece (dental problems or dentures)• Inability to maintain BH for adequate time (>20sec)• Psychological reasons• Inability to understand the procedure
• N=23 (19 BCT & 4 MRM)• Randomized cross over study• V-DIBH for fractions 1-7 & ABC for 8-14 with daily EPIDs• CBCT on 1,4,7,8,11,14• Similar OAR sparing & set up errors with both (≤ 5mm)
Error V-DIBH (N=23) ABC (N=23) P value
Set up time 9 min 11 mins 0.04
Planning CT time 24 min 27 min 0.02
Patient comfort score Higher for V-DIBH 0.007
Radiographer satisfaction score Higher for V-DIBH 0.03
Barlett FR RO 2013
Supine 3D-DIBH vs. Supine Free breathing-IMRT
• 3D-DIBH better for LAD & heart sparing• Other advantages compared to IMRT:
– Reduction in MUs– Reduction in integral dose and risk of second cancers– Reduction in dose to C/L lung and breast– Simpler planning– Possibly less impact of positioning errors– Increased clinical and financial efficiency (220%) Reardon KA, Med Dosi 2013
Osman RO 2014
Supine 3D-DIBH vs. Supine IMRT-DIBH
• IMRT results further reduction of dose in the heart and LAD-region in breath-hold
• Dosimetric study in 20 patients
Mast ME RO 2013
Benefit of DIBH proven on Cardiac gating• CT planning in free breathing and DIBH • Treatment delivery using ABC device• Cardiac MRI done after completion of RT• ECG gated axial MRI images acquired in late diastole (LD), mid diastole (MD)
& systole• Image fusion done using chest wall, aorta, intervertebral disc & spinal cord
MRI-LD MRI-MD MRI-S
Heart volumeFBDIBHDifference
628513115
53946178
52944683
LV VolumeFBDIBHRelative reduction
16.43.185%
15.51.992%
15.91.695%
Strong correlation between noted between MRI-defined whole heart and LV V22.5Gy reduction via ABC
Krauss DJ IJROBP 2005
Prone positioning• Breast (pendulous) falls away from the chest wall• Reduction in cardiac dose
• Inconsistent data (63-87% patients benefit from prone technique)
• Benefits only in large pendulous breasts• Target volume:
• Not safe for chest wall treatment or deep seated TB• Reproducibility: major concern
• CBCT is the solution but scanning increases cardiac dose and treatment time
• Regional Nodal Irradiation: dosimetry, feasibility and reproducibility• Several studies have shown reduced coverage with prone technique
Mulliez et al (R+L) Kirby et al (R+L) Whole breast
Kirby et al (R+L) Partial Breast
Supine (50) Prone (50) Supine (65) Prone (65) Supine (65) Prone (65)
Dose 40Gy/15# 50Gy/25#
Technique 6 beam IMRT non opposing
2 beam IMRT
Simple with MLC for cardiac shielding
Breast size Cup size C, mean vol 1000cc
Median cup C, 2/3 >500 cc
Reduction in dose
NR 63% 23%
Increase in dose
NR 27% 63%
No effect in dose
NR 10% 14%
Subgroup benefitted
WB-CTV >1000 cc for LAD mean only
WB-CTV >1000 cc for heart mean and LAD mean & max
WB-CTV >1000 cc for heart mean and LAD mean & max
Randomized studies
Variables affecting prone RT outcome
• Difference in contouring: whole breast CTV delineation, safety margin for LAD
• Technique of RT employed (3DCRT/IMRT)• Median breast size• Tumor bed location and delivery of SIB• Parameters reported heart/LAD/both: volumetric (V25Gy) or
dosimetric (Mean dose)• What is more important: Heart or LAD
– Those who gain through heart protection are not always those who benefit through LAD exposure (19-33% discordance)
– LAD important: Significant consequences, closest to radiation beam, displacement of the heart in prone position is greatest supero-laterally
Propositions for case selection• Mulliez & Kirby et al:
– Right-sided tumors– Left-sided tumors and large breasts – Left-sided tumors and small breasts in whom comparative planning
shows an advantage for prone position
• Chen et al:– Breast depth in prone breast < or > 7cm– Breast depth Δ (prone – supine) < or > 3cm– Breast width Δ (supine – prone) < or > 4cm
• Varga et al: Statistical model comprising of– BMI– Distance between LAD and CW – Area of heart included in the radiation field on a single CT scan at the
middle of the heart in supine position
Causes of greater set up error: shoulder discomfort or pain, underarm
discomfort, suboptimal tattoo placement (skin folds, away from midline), epigastric circumference >40cm and seroma >25cc
Position No started on planned position
No completing all #
No requiring change of plan
Supine 25 (100%) 192 (100%) 2 (8%)
Prone 21 (84%), Out of tolerance set up errors
173 (90%) 8 (24%)
Position Systematic error (mm)
Random error (mm)
Reduction in CW/clip motion (mm)
CTV_PTV expansion (mm)
Supine 1.3-1.9 2.6-3.2 2.7 ± 0.5 10
Prone 3.1-4.3 3.8-5.4 0.5 ± 0.2 12-16
Supine VBH provided superior cardiac sparing and reproducibility than a free-breathing prone position for large breasted women
Bartlett RO 2015
Measure Supine V-DIBH (n=28) Prone (N=28) P value
CBCT Data (clip based match)∑σ
≤3.0 mm ≤ 6.5 mm <0.05
≤ 3.5 mm ≤ 5.4 mm <0.05
OAR dosesHeart meanLAD mean
0.4 Gy2.9 Gy
0.7 Gy7.8 Gy
<0.001<0.001
Treatment set up 5 min 3 mins 0.01
Beam on time 24 min 27 min 0.004
Patient comfort score Higher for V-DIBH <0.01
Radiographer satisfaction score Higher for V-DIBH for the first fraction 0.06
Prone + IMRT
• Prone IMRT superior to any supine treatment only for – Right-sided breast cancer patients for lung sparing– Left-sided breast cancer patients with larger breasts (≥ 600 cc)
• The influence of treatment techniques in prone position is less pronounced for cardiac sparing
• May be beneficial for SIB delivery
HeartI/L Lung
Mulliez et al, Rad Onc 2013Brenner et al JAMA 2013
• Traditional 3DCRT plans provide inadequate nodal coverage• Prone compared to supine, and IMRT compared to 3DCRT, lowered
heart and I/L Lung doses with adequate coverage– Low dose to C/L lung, breast– Significant spinal cord dose – Match line problems– Reproducibility issues
Prone for Regional nodal irradiation
Sethi R RO 2012
SUMMARY• Selection of technique based on the target volume
• Breast Alone
• Breast + SCF ± Ax: Supine DIBH irrespective of breast size
Good compliance to breath hold
Poor complianceto breath hold
All breast sizeSupine DIBH
Large breast sizeProne without DIBH
Small breast sizeSupine/Prone depending up onVarious propositions