Timothy M. Zagar MD, Assistant Professor at the University of North Carolina, presents on Deep Inspiration Breath Hold (DIBH) with AlignRT at ASTRO 2015.

1. 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

2. Disclosures
• VisionRT

3. 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

4. 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

5. Bentel, Marks, Hardenbergh, Prosnitz, IJROBP 44:1017, 1999

6. Harvard JCRT. J Cardiovasc Magn Reson 2002;4:26
Exhalation Deep Inspiration

7. Deep Inspiration
Moves the
heart inferiorly
& posteriorly

8. DIBH allows:
•Decrease Heart
Dose
•Reduces Tumor
Bed Motion
•Decreases Lung
Dose

9. Tangent Fields

10. 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

11. How to limit cardiac dose?
• Heart Block
• DIBH
– VisionRT®, RPM (Varian®), ABC
(Beaumont)
• IMRT
– Resultant increase in low dose bath

12. Heart Block Examples
Heart Block
Midline
Marks IJROBP 1994

13. May miss breast tissue
under heart block

14. 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

15. 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

16. 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

17. 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

18. Discussion: Must be mindful
57
women
Stage 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

19. 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

20. 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