CT evaluation after neoadjuvant FOLFIRINOX chemotherapy for borderline and locally advanced pancreatic adenocarcinoma.

Aim: To assess anatomic changes on computed tomography (CT) after neoadjuvant FOLFIRINOX (5-fluorouracil/leucovorin/irinotecan/oxaliplatin) chemotherapy for secondary resected borderline resectable (BR) and locally advanced (LA) pancreatic adenocarcinoma and their accuracy to predict resectability and pathological response.
Methods: Thirty-six patients with secondary resected BR/LA pancreatic adenocarcinoma after neoadjuvant FOLFIRINOX chemotherapy (± chemoradiotherapy) were retrospectively included. Two radiologists reviewed baseline and pre-surgical CTs in consensus. NCCN (National Comprehensive Cancer Network) classification, largest axis, product of the three axes (P3A), and arterial/venous involvement were studied and compared to pathological response and resection status and to disease-free survival (DFS).
Results: Thirty-one patients had R0 resection, including only six exhibiting a downstaging according to the NCCN classification. After treatment, the largest axis and P3A decreased (P < 0.0001). The pre-surgical largest axis and P3A were smaller in case of R0 resection (P = 0.019/P = 0.021). The largest axis/P3A variations were higher in case of complete pathological response (P = 0.011/P = 0.016). A decrease of the arterial/venous involvement was not able to predict R0 or ypT0N0 (P > 0.05). Progression of the vascular involvement was seen in two (5 %) patients and led to a shorter DFS.
Conclusion: In BR/LA pancreatic adenocarcinoma after the neoadjuvant FOLFIRINOX regimen (± chemoradiotherapy), significant tumour size decreases were observed on CT. However, CT staging was not predictive of resectability and pathological response.
Key Points: • Significant tumour size decreases were observed on CT after FOLFIRINOX (± chemoradiotherapy). • CT is not able to predict R0 resection accurately after FOLFIRINOX (± chemoradiotherapy). • CT is not able to predict complete response accurately after FOLFIRINOX (± chemoradiotherapy). • Even with a stable NCCN classification, BR/LA pancreatic adenocarcinoma could have R0 resection.