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.
Bibliographical noteFunding Information:
Acknowledgements This research was supported by Yonsei University Future-leading Research Initiative of 2014 (2014-22-0151 by Minkyu Jung). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.
All Science Journal Classification (ASJC) codes
- Cancer Research