The Radiation Dose to the Left Supraclavicular Fossa is Critical for Anastomotic Leak Following Esophagectomy - A Dosimetric Outcome Analysis

Purpose: For locally advanced esophageal cancer, definitive concurrent chemoradiotherapy (CCRT) with a radiation dose of 50-50.4 Gy/25-28 Fx is prescribed, followed by adjuvant esophagectomy for better local control or salvage treatment if locoregional recurrence occurs. However, radiation injury before surgery may delay wound healing. We performed cervical anastomosis directly inside the left supraclavicular fossa (SCF), the irradiation target for esophageal cancer. The significance of radiation injury in patients with cervical anastomotic leak (AL) remains unclear. Thus, we assessed the influence of radiation on cervical AL in patients undergoing preoperative CCRT followed by esophagectomy. Patients and Methods: We defined the SYC zone, a portion of the region overlapping the left SCF. The radiation dose to the SYC zone was analyzed and correlated with AL in patients with locally advanced esophageal squamous cell carcinoma (ESCC) who were administered preoperative CCRT (radiation dose with 50-50.4 Gy/25-28 Fx to the primary esophageal tumor) followed by esophagectomy between October 2009 and January 2018. Receiver operating characteristic curve analysis and logistic regression were used to identify the optimal radiation factor to predict AL and the cutoff value. Results: The optimal radiation factor to predict AL was the mean dose to the SYC zone (area under the curve (AUC)=0.642), and the cutoff point of the mean dose was 48.55 Gray (Gy). For a mean SYC zone dose >= 48.55 Gy, the AL risk was sevenfold greater than that for <48.55 Gy (OR = 7.805; 95% CI: 1.184 to 51.446; P value = 0.033). Conclusion: Recognizing the SYC zone as an organ at risk and performing radiation evaluation are meaningful. A reduced mean dose of the SYC zone below 48.55 Gy results in a lower cervical AL rate following esophagectomy.