Background: We aimed to find the clinical value of metastatic tumor burden evaluated with F18-FDG PET/CT in gastric cancer patients, considering the human epidermal growth factor receptor 2 (HER2) status. Methods: We retrospectively reviewed 124 patients with locally advanced or metastatic gastric cancer at Yonsei Cancer Center between January 2006 and December 2014 who had undergone baseline FDG PET/CT before first-line chemotherapy. We measured the maximum standardized uptake value from the primary tumor (SUVmax) and whole-body (WB) PET/CT parameters, including WB SUVmax, WB SUVmean, WB metabolic tumor volume (WB MTV), and WB total lesion glycolysis (WB TLG), in all metabolically active metastatic lesions (SUV threshold ≥2.5 or 40% isocontour for ≤2.5), and we determined their association with patient survival outcomes. Results: SUVmax was higher in HER2-positive gastric cancers (median 12.1, range 3.4–34.6) compared to HER-2 negative (7.4, 1.6–39.1, P OpenSPiltSPi 0.001). Among all patients, WB TLG CloseSPigtSPi 600, which is indicative of a high metastatic tumor burden, showed worse progression-free survival (PFS) [hazard ratio (HR), 2.003; 95% CI, 1.300–3.086; P = 0.002] and overall survival (OS) (HR, 3.001; 95% CI, 1.950–4.618; P OpenSPiltSPi 0.001) than did WB TLG ≤ 600. Among HER2-positive gastric cancer patients treated with trastuzumab, higher metabolic tumor burden predicted worse OS, but not PFS. Conclusions: HER2-positive gastric cancers had higher SUVmax compared to HER2-negative gastric cancers. In both HER2-negative patients and -positive patients receiving trastuzumab, FDG PET/CT volume-based parameters may have a role in further stratifying the prognosis of stage IV gastric cancer.
All Science Journal Classification (ASJC) codes
- Cancer Research