Background: Postchemoradiation percentage decrease in standardized uptake value (SUV) of positron emission tomography (PET) from baseline correlates with overall survival (OS) and pathologic response. Analyses of dichotomized data are commonly reported. The authors analyzed percentage SUV decrease as both dichotomized and continuous variables.
Methods: The authors assessed 151 consecutive patients with gastroesophageal adenocarcinoma who had chemoradiation and surgery. Baseline and postchemoradiation PET/computed tomography imaging was performed. The log-rank test and Cox proportional hazards models were used to associate percentage SUV changes and OS, and logistic regression models were used to detect the association between percentage SUV changes and pathologic response.
Results: A >52% SUV decrease (dichotomized analysis) was associated with a longer OS (log-rank test, P = .023). The univariate Cox proportional hazards model indicated that greater percentage SUV decrease (as a continuous variable) was associated with a lower risk of death (hazard ratio [HR], 0.99; P = .01). Pathologic response (< or =50% residual cancer) was associated with longer OS (P = .003). Patients with chemoradiation resistance (>50% residual cancer) tended to have a higher risk of death than those with chemoradiation sensitivity (0-50% residual cancer; HR, 2.12; P = .099). In the multivariate model, the percentage SUV decrease (as a continuous variable) was the only prognosticator of OS (P = .01). The percentage SUV decrease was nonsignificantly associated with pathologic complete response (univariate odds ratio [OR], 1.01; P = .06 and multivariate OR, 1.03; P = .07).
Conclusions: The greater the decline in SUV after chemoradiation, the longer is the OS of gastroesophageal adenocarcinoma patients. The percentage SUV decrease as a continuous variable is a better prognosticator of OS than its dichotomized assessments.