Relationships between postoperative recurrences and standardized uptake value on 18F-fluorodeoxyglucose-positron emission tomography in patients with resectable and borderline resectable pancreatic ductal adenocarcinoma who underwent curative pancreatic resection after neoadjuvant chemoradiotherapy.

Background: This study aimed to examine postoperative recurrence after curative pancreatic resection following neoadjuvant chemoradiotherapy (NACRT) in patients with resectable (R-) and borderline resectable (BR-) pancreatic ductal adenocarcinoma (PDAC), focusing on its relationship with the standardized uptake value (SUV) on ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET).

Method: The postoperative initial recurrence patterns were examined in patients with R- and BR-PDAC who underwent NACRT followed by curative pancreatic resection. Data collected from three prospective clinical trials were retrospectively analysed.

Results: After a median follow-up of 29 months, 91 (60 %) of 151 patients experienced postoperative recurrence. The median recurrence-free survival (RFS) for all patients was 18 months. The sites of first recurrence were lung-only in 24 (26 %) patients, liver-only in 23 (25 %), local-only in 11 (12 %), peritoneum-only in 10 (11 %), other single site in 5 (5 %), and multiple sites in 19 (21 %) patients. Multivariate analysis identified the maximum standardized uptake value (SUVmax) on FDG-PET at diagnoses ≥5.40 (hazard ratio [HR], 1.62; 95 % confidence interval [CI], 1.01-2.61; p = 0.045) and node-positive pathology (HR, 2.01; 95 % CI, 1.32-3.08; p = 0.001) as significant predictors of RFS. Furthermore, the SUVmax at initial diagnosis and after NACRT correlated with liver metastasis.

Conclusion: R- and BR-PDACs with high SUV on FDG-PET at diagnosis are risk factors for postoperative recurrence. Among patients who undergo surgery after NACRT, those with a high SUVmax at diagnosis or post-NACRT require careful attention for postoperative liver recurrence.