Abstract
PURPOSES: Preoperative chemoradiation is a potential treatment option for localized gastric adenocarcinoma (GAC). Currently, the response to chemoradiation cannot be predicted. We analyzed the pretreatment maximum standardized uptake value (SUV(max)) and total lesion glycolysis (TLG) on positron emission tomography/computed tomography as potential predictors of the response to chemoradiation. METHODS: We analyzed the SUV(max) and TLG data from 59 GAC patients who received preoperative chemoradiation. We used logistic regression models to predict a pathologic complete response (pCR) and Kaplan-Meier curves to determine overall survival among patients with high and low SUV(max) or TLG. RESULTS: Twenty-nine patients (49%) had Siewert type III adenocarcinoma and 30 (51%) had tumors located in the lower stomach. Forty-one patients had poorly differentiated GAC, and 26 had signet ring cells. The median SUV(max) was 7.3 (0-28.2) and the median TLG was 56.6 (0-1881.5). Patients with signet ring cells had a low pCR rate, as well as a low SUV(max) and TLG. In the multivariable logistic regression model, high SUV(max) was a predictor of pCR (odds ratio = 11.1, 95% confidence interval = 2.12-50.0, p = 0.004). Overall survival was not associated with the SUV(max) (log-rank p = 0.69) or TLG (log-rank p = 0.85) CONCLUSION: A high SUV(max) was associated with sensitivity to chemoradiation and pCR in GAC, and signet ring cells seemed to confer resistance.