18F-fluorodeoxyglucose positron emission tomography to indicate conversion surgery in patients with initially unresectable locally advanced pancreatic cancer.

Abstract

Advances in chemotherapy and chemoradiotherapy have enabled conversion of initially unresectable locally advanced (UR-LA) pancreatic adenocarcinoma (PDAC) to a resectable disease. However, definitive criteria for conversion surgery have not been established. We evaluated the potential of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to indicate conversion surgery in patients with primary UR-LA PDAC. Twenty consecutive patients with UR-LA PDAC underwent chemoradiation or chemotherapy followed by assessment with FDG-PET. We defined PET responders (standardized uptake value <3.0) with marked reduction (>80%) of carbohydrate antigen 19-9 as potential candidates for conversion surgery. Outcomes were compared with those of the patients with resectable (R; n = 94) and borderline resectable (BR; n = 37) PDAC. Eight of the 20 patients (40%) were considered PET responders with marked reduction of CA19-9 and received conversion surgery (UR-LAR) 3-9 months (median, 5 months) after the initiation of therapy. Complete resection (R0) was achieved in 7 of 8 patients (87.5%) with UR-LAR. There was no significant difference in R0 rates, morbidity, or mortality among the UR-LAR, R and BR groups. The overall survival (OS) curve was better in the UR-LAR group than in the group that did not receive surgery. There was no significant difference in OS between the UR-LAR and the R or BR groups. FDG-PET could be a potential indicator for conversion surgery in patients with primary UR-LA PDAC and may help in selecting patients who qualify for complete surgical resection and have a promising prognosis.