[Experimental study on intraoperative irradiation for pancreatic cancer: histological and nutritional changes in...

For the treatment of pancreatic head cancer, pancreatoduodenectomy is followed by the intraoperative radiation therapy (IORT). The present dose adopted ranged 20 to 30 Gy, however the dose is believed to be insufficient for local control of adenocarcinoma cells. In this study, high dose IORT was performed using rabbit, so histological and nutritional changes were evaluated. Rabbits were divided in three groups; 30 Gy, 50 Gy, 80 Gy. The radiation was performed with electrons focusing base of cranial mesenteric artery (SMA in human). The rabbits were sacrificed at intervals ranging from immediately after to 4 weeks following irradiation. The earliest evidence of histological changes was the loss of endothel, although it was repaired within 1 week. Fragmentation and reduplication of internal elastic lamina were observed after 1 week, however the degree was not dose dependent. Damages of the media was observed in 50 and 80 Gy groups. That is, focal degeneration of smooth muscle cell was demonstrated in 50 Gy group and medial necrosis in 80 Gy group. Degeneration of ganglion cells was observed and its severity was dose dependent. In 80 Gy group, diarrhea occurred more frequently compared with the other groups and body weight loss couldn't recover within 4 weeks. It is concluded that, since necrosis of aortic media and marked degeneration of ganglion cells are inevitable in 80 Gy group, IORT dose should be increased within 50 Gy.