Background: The prognostic impact of preoperative 18 F-FDG PET/CT in advanced gastric cancer (AGC) remains a matter of debate. This study aims to evaluate the prognostic impact of SUV max in preoperative 18 F-FDG PET/CT of AGC according to histologic subtype, with a focus on the differences between tubular adenocarcinoma and signet ring cell (SRC) carcinoma. Methods: As a discovery set, a total of 727 AGC patients from prospective database were analyzed according to histologic subtype with Cox proportional hazard model and p-spline curves. In addition, another 173 patients from an independent institution was assessed as an external validation set. Results: In multivariate analysis, high SUV max in preoperative 18 F-FDG PET/CT of AGC was negatively correlated with disease-free survival (DFS) and overall survival (OS) in patients with diffuse type (DFS: HR 2.17, P < 0.001; OS: HR 2.47, P < 0.001) or SRC histology (DFS: HR 2.26, P = 0.005; OS: HR 2.61, P = 0.003). This negative prognostic impact was not observed in patients with intestinal type or well or moderately differentiated histology. These findings have been consistently confirmed in a validation set. The p-spline curves also showed a gradual increase in log HR as SUV max rises only for SRC histology and for diffuse-type AGC. Finally, a novel predictive model for recurrence of AGC with diffuse type or SRC histology was generated and validated based on the preoperative SUV max . Conclusions: Preoperative high SUV max of AGC is a poor prognostic factor in those with diffuse type or SRC histology. This study is the first to demonstrate the differential prognostic impact of preoperative PET/CT SUV max in AGC according to histologic subtype and provide a clue to explain previous discrepancies in the prognostic impact of preoperative PET/CT in AGC. Prospective studies are required to validate the role of preoperative SUV max in AGC.
Bibliographical noteFunding Information:
Acknowledgements This work was supported by the National
Research Foundation of Korea (NRF) Grant funded by the Ministry of Science, ICT and Future Planning (Grant NRF-2016M3A9E8941664 to H.C. NRF-2016R1C1B2014671 to C.K.) and by a Grant from the National R&D Program for Cancer Control, Ministry of Health and Welfare (Grant 1520190 to S.Y.R).
Conflict of interest Research grants from funding agencies: the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science, ICT and Future Planning (Grant NRF-2016M3A9E8941664 to H.C. NRF-2016R1C1B2014671 to C.K.) and the Grant from the National R&D Program for Cancer Control, Ministry of Health and Welfare (Grant 1520190 to S.Y.R). Honoraria for speaking at symposia: no. Financial support for attending symposia: no. Financial support for educational programs: no. Employment or consultation: no. Support from a project sponsor: no. Position on advisory board or board of directors or other type of management relationships: no. Multiple affiliations: no. Financial relationships, for example equity ownership or investment interest: no. Intellectual property rights (e.g. patents, copyrights and royalties from such rights). Holdings of spouse and/or children that may have financial interest in the work: no.
All Science Journal Classification (ASJC) codes
- Cancer Research