The clinical implications of FDG-PET/CT differ according to histology in advanced gastric cancer

• Published in: Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association Vol. 22; no. 1; pp. 113 - 122
• Main Authors: Chon, Hong Jae, Kim, Chan, Cho, Arthur, Kim, Yoo Min, Jang, Su Jin, Kim, Bo Ok, Park, Chan Hyuk, Hyung, Woo Jin, Ahn, Joong Bae, Noh, Sung Hoon, Yun, Mijin, Rha, Sun Young
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.01.2019; Springer Nature B.V
• Subjects: Abdominal Surgery; Adenocarcinoma; Adenocarcinoma - diagnostic imaging; Adenocarcinoma - mortality; Adenocarcinoma - pathology; Adult; Aged; Aged, 80 and over; Cancer Research; Disease-Free Survival; Female; Fluorodeoxyglucose F18; Gastric cancer; Gastroenterology; Histology; Humans; Intestine; Kaplan-Meier Estimate; Male; Medicine; Medicine & Public Health; Middle Aged; Multivariate analysis; Oncology; Original; Original Article; Positron emission tomography; Positron Emission Tomography Computed Tomography; Prognosis; Proportional Hazards Models; Radiopharmaceuticals; Stomach Neoplasms - diagnostic imaging; Stomach Neoplasms - mortality; Stomach Neoplasms - pathology; Surgical Oncology; Signet ring cell carcinoma; Diffuse type; Advanced gastric cancer; Prognostic impact; PET/CT
• ISSN: 1436-3291; 1436-3305; 1436-3305
• DOI: 10.1007/s10120-018-0847-5

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.