Prospective Assessment of Deep Inspiration Breath Hold to Prevent Radiation-Induced Cardiac Perfusion Defects in Left-Sided Breast Cancer
- 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
- 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
- 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