Effect and Toxicity of Bilateral Supraclavicular Lymph Node Irradiation on Stage III Lower Thoracic Esophageal Cancer After Radical Surgery

Abstract

Surgery is the most important treatment for patients with lower thoracic esophageal squamous cell carcinoma (LTEC). Treatment failures, especially loco-regional recurrence involving mediastinal, abdominal, and supraclavicular lymph nodes area, are common after radical esophagectomy. Post-operative radiotherapy (PORT) has been demonstrated to benefit patients with stage III disease. However, whether bilateral supraclavicular lymph node radiotherapy should be included in the clinical target volume (CTV) remains unclear for those patients with lower thoracic esophageal cancer. So, we aim to explore whether PORT including the bilateral supraclavicular region can reduce the recurrence of supraclavicular lymph node, prolong overall survival and control distant metastasis in patients with stage III LTEC. We retrospectively analyzed 79 patients with stage III LTEC who had undergone radical surgery and PORT between 2010 and 2014. Among these patients, 51 patients received PORT which CTV excluding the bilateral supraclavicular lymph node region (Group A), and the remaining 28 patients received PORT which CTV including the supraclavicular region (Group B). Clinical outcomes (including local control, survival time, side-effects and prognostic factors) were analyzed with SPSS 25.0. Follow-up to August 2016, the 1-, 2-, and 3-year supraclavicular lymph nodes metastasis rates were 15.7%, 41.2%, 45.1% in Group A, 10.7%, 10.7%, 10.7% in Group B. The median overall survival (OS) of Group A and Group B were 25 and 24.5 months respectively. Univariate and multivariate analysis indicated that radiotherapy to the supraclavicular region decreased supraclavicular lymph node recurrence (p = 0.007/0.016, respectively) but did not prolong OS (p = 0.273/0.324) or control distant metastasis (p = 0.760/0.804). Our data also indicated that PORT including the supraclavicular region was not associated with the increase of radiotherapy-related complications (all p > 0.05). PORT including the bilateral supraclavicular region can reduce the recurrence of supraclavicular lymph node in patients with stage III LTEC without increase of treatment-related toxicities. However, PORT including bilateral supraclavicular region failed to prolong OS or control distant metastasis. Further prospective studies are warranted.