Purpose: This study investigated the relationship between tumor volume and outcomes in patients receiving trimodality therapy for locally advanced esophageal cancer.
Methods: Between 2001 and 2012, 67 patients treated for esophageal cancer with chemoradiotherapy followed by esophagectomy who had available gross tumor volume (GTV) information were analyzed (35 node-negative, 32 node-positive patients with primary and nodal GTV contoured as separate regions of interest). All gross tumor volumes (GTVs) were contoured at the time of radiotherapy treatment planning. GTV optimal cutoff values were determined with receiver operating characteristic analysis and deemed significant when χ (2) analysis demonstrated differences in examined prognostic variables. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Cox proportional hazards model.
Results: GTVprimary (P = 0.034) and N stage were significant multivariate predictors for improved local control; GTVprimary was the only multivariate predictor of PFS (P = 0.0299) and OS (P = 0.001228) at 5 years. Univariate predictors of 5-year PFS and OS included GTVprimary, node number, and metastatic lymph node ratio. GTVprimary >85 cc was the best predictor for local failure (33.3 %; 8.7 % if ≤85 cc). GTVprimary >46 cc correlated with an increased risk of 5-year distant failure (37.1 %; 6.7 % if ≤46 cc).
Conclusions: GTVprimary was a significant multivariate predictor for improved local control, PFS, and OS. GTVprimary is a more powerful predictor of patient outcomes than traditional TNM staging and should be part of the decision-making process when determining optimal local and systemic options for patients with locally advanced esophageal cancer.