Characterization of Pancreatic Tumor Motion Using Cine MRI: Surrogates for Tumor Position Should Be Used With Caution

Motion of pancreatic tumor borders is highly variable between patients and larger than expected. There is substantial deformation with breathing, and tumor border position does not correlate well with abdominal wall or diaphragmatic position. Current motion management strategies may not account fully for tumor motion and should be used with caution.