Respiratory motion of lymph node stations in pancreatic cancer: Analyses using contrast-enhanced four-dimensional computed tomography.

Abstract

Data regarding respiratory motion of lymph node (LN) stations in pancreatic cancer is limited. Therefore, we assessed their respiratory motion using contrast-enhanced four-dimensional-computed tomography (CE-4DCT). We evaluated respiratory motion in 18 pancreatic cancer patients. We selected LN stations around major arteries which were visible on CE-4DCT images. This included the common hepatic, celiac, splenic, and superior mesenteric stations. Two radiation oncologists individually delineated the gross tumor volume (GTV) and the LN stations as observers 1 and 2. The respiratory motion of the celiac (median, 3.9 mm each for both observers) and superior mesenteric (median, 4.5 and 5.0 mm for observers 1 and 2, respectively) stations in the craniocaudal (CC) directions was significantly smaller than that of the GTV (median, 8.9 and 7.8 mm for observers 1 and 2, respectively). The respiratory motion of the common hepatic station (median, 3.8 and 3.6 mm for observers 1 and 2, respectively) in the anterior-posterior (AP) direction was significantly larger than that of the GTV (median, 2.8 and 2.2 mm for observers 1 and 2, respectively). We observed significant differences in respiratory motion between the GTV and the LN stations in pancreatic cancer.