¹⁸F-FDG PET/CT imaging biomarkers for early and late evaluation of response to first-line chemotherapy in patients with pancreatic ductal adenocarcinoma

Abstract

Purpose: The purpose of this study was to evaluate ¹⁸F-FDG-PET/CT as an early and late interim imaging biomarker in patients with pancreatic ductal adenocarcinoma (PDAC) who undergo first-line systemic therapy. Methods: This was a prospective, single-center, single-arm, open-label study (IRB12-000770). Patient receiving first line chemotherapy were planned to undergo a baseline ¹⁸F-FDG-PET/CT (PET1), early interim ¹⁸F-FDG PET/CT (PET2) and late interim ¹⁸F-FDG-PET/CT (PET3). ROC selected and established (mPERCIST / RECIST1.1) cut-offs for metabolic and radiographic tumor response assessment were applied. Patients were followed to collect data on further treatments and overall survival (OS). Results: The study population consisted of 28 patients who underwent PET1. Twenty-three of these (82%) underwent PET2 and 21 (75%) PET3, respectively. Twenty-three deaths occurred during a median follow up period of 14 months (maximum follow up, 58.3 months). The median OS was 36.2 months (95%CI, 28-NYR) in early metabolic responders (6/23 (26%), P = 0.016) and 25.4 months (95%CI, 19.6-NYR) in early radiographic responders (7/23 (30%), P = 0.16). The median overall survival was 27.4 months (95%CI, 21.4-NYR) in late metabolic responders (10/21 (48%), P = 0.058) and 58.2 months (95%CI, 21.4-NYR) in late radiographic responders (7/21 (33%), P = 0.008). Conclusion: ¹⁸F-FDG PET may serve as early interim imaging biomarker (~ at 4 weeks) for evaluation of response to first-line chemotherapy in patients with PDAC. Radiographic changes might be sufficient for response evaluation after the completion of first line chemotherapy.