Clinical usefulness of ¹⁸F-fluorodeoxyglucose-positron emission tomography in patients with locally advanced pancreatic cancer planned to undergo concurrent chemoradiation therapy.

PURPOSE: To assess the role of coregistered (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in detecting radiographically occult distant metastasis (DM) at staging in patients with locally advanced pancreatic cancer (LAPC) and to study whether FDG-PET parameters can predict relatively long-term survival in patients who are more likely to benefit from chemoradiation therapy (CRT). METHODS AND MATERIALS: From our institutional database, we identified 388 LAPC patients with M0 on conventional computed tomography (CT) who were planned to undergo CRT. Coregistered FDG-PET staging was offered to all patients, and follow-up FDG-PET was used at the clinical discretion of the physician.
RESULTS: FDG-PET detected unsuspected CT-occult DM in 33% of all 388 patients and allowed them to receive systemic therapy immediately. The remaining 260 patients (PET-M0) underwent CRT selectively as an initial treatment. Early DM arose in 13.1% of 260 patients, and the 1-year estimated locoregional recurrence rate was 5.4%. Median overall survival (OS) and progression-free survival (PFS) were 14.6 and 9.3 months, respectively, at a median follow-up time of 32.3 months (range, 10-99.1 months). Patients with a baseline standardized uptake value (SUV) <3.5 and/or SUV decline ≥60% had significantly better OS and PFS than those having none, even after adjustment for all potential confounding variables (all P<.001).
CONCLUSIONS: FDG-PET can detect radiographically occult DM at staging in one-third of patients and spare them from the potentially toxic therapy. Additionally, FDG-PET parameters including baseline SUV and SUV changes may serve as useful clinical markers for predicting the prognosis in LAPC patients.