PV QA 4 - Poster Viewing Q&A 4
Purpose/Objective(s): Aim of the current comparative modelling study was to estimate the individual radiation-induced risk for death of ischemic heart disease (IHD) under free breathing (FB) and deep inspiration breath hold (DIBH) in a real-world population.
Materials/Methods: Eighty-nine left-sided breast-cancer patients were enrolled in the prospective SAVE-HEART study (German Clinical Trials Register no.: DRKS00011213). For each patient three-dimensional conformal treatment plans in FB and DIBH were calculated. Patients were between 40 and 75 years old and without major cardiovascular preconditions. All patients received a detailed cardiac assessment of cardiovascular risk factors prior to radiotherapy. Radiation-induced risks of IHD mortality were estimated for each patient based on individual IHD risk factors and the relative radiation-induced risk.
Results: For the entire patient cohort, the mean calculated absolute 10-year IHD mortality risk was 0.14% and the lifetime risk was 1.6% for treatments in FB. With the use of DIBH, mean heart doses and estimated IHD risks were reduced by 35% (interquartile range: 23% - 46%) as compared to FB. Mean expected years of life lost (YLL) due to radiation-induced IHD mortality were 0.11 years in FB, and 0.07 years in DIBH. Expected YLL were remarkably independent of treatment age in patients with favourable tumour prognosis and increased with age otherwise. DIBH lead to more pronounced reductions in YLL in patients with high baseline risk (0.08 years for upper quartile vs. 0.02 years for lower quartile), in patients with favourable tumour prognosis (0.05 years for patients without involvement of lymph nodes vs. 0.02 years with involvement) and in patients with high mean heart doses in FB (0.09 years for doses >3 Gy vs. 0.02 years for doses <1.5 Gy).
Conclusion: In view of the large number of breast cancer survivors, heart radiation exposure is an important risk factor for IHD mortality. The deep-inspiration-breath-hold technique is an effective countermeasure and should best be offered to all left-sided patients. However, highest benefits are expected for patients with favourable tumour prognosis, high mean heart dose or high baseline IHD risk, independently of their age.
The asset you are trying to access is locked. Please enter your access key to unlock.