Deep Inspiration Breath-hold for Left-sided Breast Cancer Patients with Unfavorable Cardiac Anatomy Requiring Internal Mammary Nodal Irradiation

Publication date: Available online 13 April 2017
Source:Practical Radiation Oncology
Author(s): Osama Mohamad, Jean Shiao, Bo Zhao, Karen Roach, Ezequiel Ramirez, Dat Vo, Kimberly Thomas, Xuejun Gu, Ann Spangler, Kevin Albuquerque, Asal Rahimi
PurposeTo evaluate the utility of moderate deep inspiration breath-hold (mDIBH) in reducing heart exposure in left breast cancer patients who have unfavorable cardiac anatomy and need internal mammary nodal (IMLN) irradiation (RT).Material and MethodsWe used maximum heart distance (MHD), defined as maximum distance of heart within the treatment field, >1cm as a surrogate for unfavorable cardiac anatomy. Twenty-two left breast cancer patients with unfavorable cardiac anatomy requiring IMLN-RT underwent free-breathing (FB) and mDIBH CT simulation and planning. 3D–partially wide tangents (3D–PWT) and IMRT plans were generated. Dose-volume histograms were used to compare heart and lung dosimetric parameters. Duration of treatment delivery was recorded for all fractions.ResultsMHD decreased significantly in mDIBH scans. mDIBH significantly reduced mean heart dose (222.7 vs. 578.4cGy; p<0.0001) and left lung V20Gy (31.93 vs. 38.41%; p=0.0006) in both 3D–PWT and IMRT plans. ΔMHD(FB-BH), defined as the change in MHD after breath-hold, reliably predicted mean heart dose reduction after mDIBH. Radiation was effectively delivered in 11.31±3.40min with an average of 10.06±2.74 breath-holds per fraction.ConclusionsmDIBH is efficient and can effectively decrease mean heart dose in patients with unfavorable cardiac anatomy who need IMLN-RT thus simplifying planning and delivery for them. The reduction in mean heart dose is proportional to the reduction in maximum heart distance.



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