An Institutional Audit of Maximum Heart Dose in Patients Treated With Palliative Radiotherapy for Non-small Cell Lung Cancer

Background/Aim: Recent studies suggested that high unintended radiation doses to the heart may reduce survival of patients with non-small-cell lung cancer (NSCLC) irradiated with curative intent. In the palliative setting, limited information is available. Therefore, we analyzed a single institution cohort of 165 patients. Patients and Methods: Patients in this retrospective study received palliative (chemo)radiotherapy (at least 30 Gy). Typical radiation doses were 10-13 fractions of 3 Gy and 15 fractions of 2.8 Gy. Heart dose constraints were not employed during treatment planning. The maximum dose to 1 cc of the heart was registered and converted into the equivalent dose in 2-Gy fractions (EQD2). Results: The median heart dose (maximum to 1 cc) was 26 Gy (range=11-42 Gy). This dose corresponded to 28-108% of the prescription dose. After conversion into EQD2, the median maximum heart dose to 1 cc was 26 Gy, range=10-58 Gy). Neither higher T-stage nor higher N-stage predicted for higher maximum heart EQD2. The maximum heart EQD2 was not associated with overall survival. Conclusion: The current practice of focusing on sparing of lungs and esophagus appears acceptable in the context of palliative regimes. To further strengthen this strategy, additional studies looking at cardiac substructures and other dosimetric variables such as mean dose are warranted.