Comparison of the treatment results of involved-field and elective nodal irradiation in locally advanced esophageal cancer

In recent years, concurrent chemoradiotherapy (CCRT) has become a standard treatment modality for patients with locally advanced esophageal cancer. On the other hand, there is no international consensus regarding an accurate definition of the clinical target volume (CTV). This study evaluated the clinical outcomes in patients with locally advanced esophageal cancer treated definitively with either (ENI) elective nodal irradiation or (IFI) involved-field irradiation.

Retrospective analysis of the treatment results for patients with locally advanced esophageal cancer between 2001.5 and 2013.5 was carried out. The eligible patients had T2-4N0-2M0 biopsy-proven squamous cell carcinoma (SCC) of the esophagus and were treated with a curative aim. Patients treated with surgery or radiotherapy alone were excluded. The gross tumor volume (GTV) was delineated based on the FDG-PET CT scans. Patients treated with ENI received radiotherapy on the supraclavicular or celiac area as the clinical target volume (CTV). For IFI planning, CTV is defined as a 3-cm superoinferior margin and a 1-cm lateral margin from the GTV. The 3-year progression-free survival, overall survival and patterns of the failures were analyzed.

A total of 99 patients who completed CCRT were eligible for the analysis. Of the patients, 50 patients had ENI and 49 patients had IFI. The age, gender and staging were similar in both groups. The median follow-up was 21 months. Both groups showed a similar overall survival (p = 0.293). On the other hand, although not statistically significant, the IFI group showed a tendency for lower 3-year progression-free survival rates, particularly the non-surgery group (25 vs. 46 %, p = 0.075). The cumulative failure rates were significantly lower in the ENI group than in the IFI group. (35 vs. 56 %, p = 0.04).

Definitive CCRT with ENI did not improve the survival and disease control for patients with esophageal SCC. The omission of ENI was associated with a higher failure rate, but it did not affect the survival time. PET-CT-guided involved-field irradiation is a reasonable option for most locally advanced thoracic esophageal cancer but needs caution for patients who will not undergo surgery.