Risk factors and prognosis for supraclavicular lymph node metastasis in patients with thoracic esophageal cancer. Distant or regional metastasis?

We aimed to determine the frequency and prognosis of supraclavicular (#104) lymph node (LN) metastasis compared with other LN stations in patients with advanced thoracic esophageal cancer and to identify risk factors for metastasis to delineate the indications for three-field lymphadenectomy (3FL). The study cohort of 567 eligible patients with esophageal cancer had undergone subtotal esophagectomy from 2003 to 2020. LN metastasis was defined as pathologically proven metastasis or positron emission tomography-positive LNs. The efficacy index (EI), calculated from the frequency of LN metastases and survival rates, was used as prognostic value of each LN station dissection for patient survival. Risk factors for #104 LN metastasis were determined by multivariable logistic regression. The frequency of #104 LN metastasis was 11.6% overall, 31.7% in upper and 8.3% in middle/lower third lesion. Neoadjuvant chemotherapy was administered to 71% of patients and chemo-radiation to 11%. The 5-year overall survival was 45.8%. The EI for #104 LNs (5.3) was similar to that for #101 LNs. Risk factors were age < 65 years, upper third lesion, clinical N2-3, #101/106rec LN metastasis and poorly differentiated carcinoma. The 5-year overall survival of patients with middle/lower lesions was 38% (EI 3.1), similar to that for #101 and #8/9/11 LNs. The prognosis of patients with #104 LN metastases is similar to that of patients with metastases in other regional LN stations. Therefore, we recommend 3FL exclusively for patients at a high risk of #104 LN metastasis due to the overall metastatic rate not being high.