Metabolic activity to predict clinical response and prognosis in esophageal adenocarcinoma patients treated with bimodality.

Abstract

127 Background: Patients with localized esophageal adenocarcinoma (L-EAC) who are not suitable for surgery receive definitive chemoradiation. However, there are no biomarkers or imaging variables to predict clinical complete response (cCR; negative bx and physiologic PET post chemoradiation) or prognosticate favorable overall survival (OS). We analyzed tumor metabolic activity by standardized uptake value (SUV) or total lesion glycolysis (TLG). Methods: 266 patients with L-EAC, who declined or were unsuitable for surgery, were analyzed. Cox proportional hazards regression model for OS was analyzed using categorized SUV (low; < 6.5, moderate; 6.5-12.9, or high; ≥12.9) or TLG (low; < 24.2, moderate; 24.2-82.6, or high; ≥82.6). Logistic regression model for cCR was analyzed using categorized SUV (low; < 5.4 or high; ≥5.4) or TLG (low; < 27.0 or high; ≥27.0). Results: Mean SUV and TLG were 12.8 ± 10.7 and 209 ± 376.8, respectively. Both SUV and TLG were significantly associated with the length of the tumor (p < 0.0001) and clinical stage (p < 0.0001). Higher SUV and TLG were significantly associated with shorter OS than low SUV and TLG (moderate SUV; HR 1.79, CI 1.19-2.69, high SUV; HR 2.82, 1.90-4.18, moderate TLG; HR 1.82, 1.14-2.90, high TLG; 3.16, 2.11-4.74). 68 patients (28%) achieved cCR and remained free of recurrence. In the multivariate logistic regression model, low SUV and low TLG highly predicted cCR without recurrence (low SUV; OR 3.15, 1.38–7.19, low TLG; OR 4.79, 2.28-10.08). Conclusions: Tumor metabolic activity is highly associated with prognosis and response to chemoradiation in patients with L-EAC not undergoing surgery. Further refinements (addition of biomarkers) could allow personalized care of these patients.