Residual Setup Errors Towards the Heart After Image Guidance Linked With Poorer Survival in Lung Cancer Patients: Do We Need Stricter IGRT Protocols?

Residual shift metrics derived from IGRT data can categorize patients with non-small cell lung cancer and those with esophageal cancer into populations with significantly different survival times on the basis of the size of the residual shift in the direction of the heart, thus providing evidence of the importance of using strict IGRT protocols to spare organs at risk and highlighting the heart as a dose-sensitive organ.