Diagnostic performance of FDG PET/CT for surveillance in asymptomatic gastric cancer patients after curative surgical resection

Purpose The present study evaluated the diagnostic performance of 2-[F-18] fluoro-2-deoxy-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) for surveillance in asymptomatic gastric cancer patients after curative surgical resection. Methods We retrospectively recruited 190 gastric cancer patients (115 early gastric cancer patients and 75 advanced gastric cancer patients) who underwent 1-year (91 patients) or 2-year (99 patients) postoperative FDG PET/CT surveillance, along with a routine follow-up program, after curative surgical resection. All enrolled patients were asymptomatic and showed no recurrence on follow-up examinations performed before PET/CT surveillance. All PET/CT images were visually assessed and all abnormal findings on follow-up examinations including FDG PET/CT were confirmed with histopathological diagnosis or clinical follow-up. Results During follow-up, 19 patients (10.0 %) developed recurrence. FDG PET/CT showed abnormal findings in 37 patients (19.5 %). Among them, 16 patients (8.4 %) were diagnosed as cancer recurrence. Of 153 patients without abnormal findings on PET/CT, three patients were false-negative and diagnosed as recurrence on other follow-up examinations. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET/CT were 84.2 %, 87.7 %, 43.2 %, and 98.0 %, respectively. Among 115 early gastric cancer patients, PET/CT detected recurrence in four patients (3.5 %) and one patient with local recurrence. Among 75 advanced gastric cancer patients, PET/CT detected recurrence in 12 patients (16.0 %), excluding two patients experiencing peritoneal recurrence. In addition, FDG PET/CT detected secondary primary cancer in six (3.2 %) out of all the patients. Conclusions Post-operative FDG PET/CT surveillance showed good diagnostic ability for detecting recurrence in gastric cancer patients. FDG PET/CT could be a useful follow-up modality for gastric cancer patients, especially those with advanced gastric cancer. However, further careful evaluation is needed because of false-positive findings on PET/CT.