Failure patterns in patients with esophageal cancer treated with definitive chemoradiation

Abstract

Background: Local failure after definitive chemoradiation therapy for unresectable esophageal cancer remains problematic. Little is known about the failure pattern based on modern-day radiation treatment volumes. We hypothesized that most local failures would be within the gross tumor volume (GTV), where the bulk of the tumor burden resides.

Methods: We reviewed treatment volumes for 239 patients who underwent definitive chemoradiation therapy and compared this information with failure patterns on follow-up positron emission tomography (PET). Failures were categorized as within the GTV, the larger clinical target volume (CTV, which encompasses microscopic disease), or the still larger planning target volume (PTV, which encompasses setup variability) or outside the radiation field.

Results: At a median follow-up time of 52.6 months (95% confidence interval, 46.1-56.7 months), 119 patients (50%) had experienced local failure, 114 (48%) had distant failure, and 74 (31%) had no evidence of failure. Of all local failures, 107 (90%) were within the GTV, 27 (23%) were within the CTV, and 14 (12%) were within in the PTV. On multivariate analysis, GTV failure was associated with tumor status (T3/T4 vs T1/T2; odds ratio, 6.35; P = .002), change in standardized uptake value on PET before and after treatment (decrease >52%: odds ratio, 0.368; P = .003), and tumor size (>8 cm, 4.08; P = .009).

Conclusions: Most local failures after definitive chemoradiation for unresectable esophageal cancer occur in the GTV. Future therapeutic strategies should focus on enhancing local control.

Figure 1

Demonstration of various failure patterns based on the original treatment planning coronal CT scans (on the left) illustrating the treated radiation volume, with matched post treatment PET scans (on the right) demonstrating recurrence patterns, which are visible as bright spots on the fusion PET/CT scans. 1A) Failure in the gross tumor volume (GTV) in the center of the treatment field. 1B) Failure in the clinical target volume (CTV), GTV in green, CTV in yellow and PTV in teal. 1C) Failure within the planning target volume (PTV). 1D) Failure outside the PTV.

Figure 2

Patterns of local failures based on the original radiation treatment volumes, 90% within the gross tumor volume (GTV), 23% in the clinical target volume (CTV), and 12% in the planning target volume (PTV).

Figure 2

Patterns of local failures based on the original radiation treatment volumes, 90% within the gross tumor volume (GTV), 23% in the clinical target volume (CTV), and 12% in the planning target volume (PTV).

Figure 3

Kaplan-Meier estimates of overall survival according to failure within the gross tumor volume after definitive chemoradiation therapy for unresectable esophageal cancer compared to all other patients without GTV failure.