ERT following IORT improves survival of patients with resectable pancreatic cancer

Background/Aims: The clinical course of patients with pancreatic carcinoma remains dismal despite the recent advances of diagnostic and therapeutic procedures. One of the main causes is residual carcinoma cells, especially at the retroperitoneal aspect after pancreatectomy. Radiation therapy (RT) [intraoperative radiation therapy (IORT) and external radiation therapy (ERT)] is a therapeutic strategy to conquer the remaining cancer cells. Methodology: Effects of RT were retrospectively examined in 81 patients with pancreatectomy for pancreatic cancer together with early and late complications. Results: Preoperative clinical data were not different between the RT(+) and RT(-) groups excluding peripheral lymphocyte counts. Postoperative early complications equally occurred including pancreatic fistula. Regarding late complications (>2 months after operation), stomal ulcer, vertebral fracture, pseudoaneurysm, intraabdominal hemorrhage, and liver abscess were present only in patients with RT. Glucose intolerance tended to be more frequent in the RT (+) group, i.e. 12 (63%) of the 19 with RT examined and 14 (42%) of the 33 without RT examined. Follow-up imaging showed recurrence in 27 (71%) of the 38 patients without RT and 13 (52%) of the 25 patients with RT. The sites of the recurrence were not different by the presence or absence of RT. One-year, 3-year and 5-year cumulative survival rates were similar between the RT (-) group (100%, 39%, 21%, respectively) and IORT (+) alone group (100%, 29% and 17%, respectively). The rates in the IORT (+) and ERT (+) group were 100%, 54% and 28%, respectively, which tended to be better than those in the other two groups, but the differences were not statistically significant. Conclusions: These findings suggest that only the combination of IORT and ERT somewhat improves the short-term clinical course of patients with resectable pancreatic cancer, although there are some RT-related late complications. It is recommended that ERT be added to IORT after pancreatectomy for pancreatic cancer to improve the clinical course, once IORT has been performed.