126 Background: It is known that esophageal cancer frequently causes lymph node metastasis. Even if relatively early stage of esophageal cancer, reaching muscularis mucosae (T1a-MM: Japanese Classification of Esophageal Cancer) causes subclinical node metastasis to about 10%. So when radiation therapy (RT) is administered to these patients, field of irradiation should include the areas where subclinical node metastasis may exist. But the wider field of irradiation is, the more likely adeverse event is to occur. In this study, we examined utility of RT based on sentinel lymph node (SLN) theory. Methods: Before irradiation, Tc-99m tin colloid solution was endoscopically injected to the submucosal layer around the primary tumor and lymphoscintigraphy was examined to detect SLNs. And the irradiation field was planned as SLN regions were included. Patients with esophageal squamous cell carcinomas (ESCC) that reach cT1a-MM or cT1b and patients with ESCC who had underwent endoscopic resection and pathologically diagnosed pT1a-MM or pT1b were eligible if they had clinically no lymph node metastasis, no distant metastasis and no advanced cancer in other site. Between April 2001 and December 2009, 17 of these patients were received RT based on SLN theory. We retrospectively examined them. Results: Characteristics of the 17 pts were: median age; 67 (58-82), male/female; 15/2, T1a-MM/T1b-SM1/T1b-SM2; 4/2/11, definitive RT/adjuvant RT; 10/7, RT alone/concurrent chemoradiotherapy; 1/16. Average dose of irradiation was 57.0 ± 6.4Gy. Median follow-up is 81.4 months (7.9-127.2). Ten pts with definitive RT gained complete remission. Two minor local relapses of the primary tumors were observed. They underwent salvage endoscopic resection and survive without other relapse. There was no treatment related death. Grade 3 or 4 late toxicity was not observed. No significant financial relationships to disclose.
Endoscopic Resection for Early-Stage Esophageal Cancer, Are We There for Squamous As Well?