Date post: | 17-Jan-2017 |
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Timothy M. Zagar, M.D.October 19, 2015
Prospective Assessment of Deep Inspiration Breath Hold to Prevent
Radiation-Associated Cardiac Perfusion Defects in Patients with
Left-Sided Breast Cancer
Disclosures• VisionRT
Background• RT-associated cardiac disease is real
• Patients die from this
• Clinically relevant cardiac damage takes years to manifest– Not necessarily decades as previously
thought
Darby SC, et al. N Eng J Med 368:987-998, 2013 Cuzick J, et al. Cancer Treat Rep 71:15-29, 1987
The Oxford Review• 42,000 patients from 78 randomized
trials– 23,500 RT versus no RT
• The use of RT improved LC, BCSM and OS
• However, there was an increased risk of non-cancer mortality in RT patients, primarily from:– Heart disease: RR 1.27
EBCTCG Lancet 366:2087-2106, 2005
Bentel, Marks, Hardenbergh, Prosnitz, IJROBP 44:1017, 1999
Harvard JCRT. J Cardiovasc Magn Reson 2002;4:265-71
Exhalation Deep Inspiration
Deep Inspiration
Moves the heart inferiorly & posteriorly
DIBH allows:
•Decrease Heart Dose
•Reduces Tumor Bed Motion
•Decreases Lung Dose
Tangent Fields
How do we image cardiac defects?
• Nearly 50% of patients had a perfusion defect at 6 months
• Though significance of perfusion defects is unclear Marks LB et al IJROBP 63:214-223, 2005
How to limit cardiac dose?
• Heart Block
• DIBH– VisionRT®, RPM (Varian®), ABC
(Beaumont)
• IMRT– Resultant increase in low dose bath
Heart Block Examples
Heart Block
Midline
Marks IJROBP 1994
May miss breast tissue under heart block
Methods• Left-sided breast cancer pts were
enrolled on an IRB-approved, single-arm prospective clinical study to assess DIBH
• Each patient received a pre-RT SPECT-CT rest-cardiac gated perfusion scan
• All patients received tangential radiation to the breast/chest wall. Typical doses: 2 Gy x 25 fractions or 2.67 Gy x 16 fractions
Methods• To design the RT plan, DIBH and
conformal blocking was used to assure that the heart was excluded from the primary RT beam
• At six months port-RT, the SPECT-CT was repeated
• The perfusion and motion images were assessed qualitatively by a nuclear medicine physician
Results• Twenty-five patients enrolled; four
were not evaluable due to abnormal pre-RT SPECT scan, one was lost to follow-up
• Of the 20 evaluable patients, all completed the tangential radiation course; five also received regional nodal RT as well; and 18/19 received a tumor bed boost
Results• The mean heart dose ranged from
42-160cGy for the 20 patients. Mean of the mean heart dose over all patients was 78 cGy
• Six month follow-up SPECT scans have been obtained for 14 patients, to date
• All 14 have a normal post-RT SPECT scan; and/or no change from pre-RT cardiac perfusion status
Discussion: Must be mindful
57 womenStage I-III L breast cancer
SPECT
DIBH RT
Standard breast RT SPECT
SPECT
Zellars RC et al. Int J Radiat Oncol Biol Phys. 2014 Mar 15;88(4):778-85
Hopkins Randomized• Despite randomization, DIBH pts more
likely– To be younger (median age 51 vs. 62)– To have received chemotherapy (52% vs. 18%)
• Pts treated with DIBH had MORE cardiac apical perfusion defects– Perhaps not as reproducible– Dr’s may have been too tight on their heart
block• Though significance of perfusion defects is
unclear (repeat)Zellars RC et al. Int J Radiat Oncol Biol Phys. 2014 Mar 15;88(4):778-85
Conclusions• DIBH treatment techniques are well-
tolerated by most breast cancer patients
• Mean dose to the heart can be reduced using DIBH techniques
• Cardiac avoidance with DIBH appears to be able to prevent the development of RT-associated cardiac perfusion abnormalities