Multidisciplinary approach for cT1bN0 esophageal cancer.

133 Background: The standard treatment for cT1bN0 esophageal squamous cell carcinoma (ESCC) was once surgery, but endoscopic submucosal dissection (ESD) following by additional treatment (ESD+α) are now being applied. Accordingly, we examined treatment outcomes for cT1bN0 ESCC to assess the validity of these treatments in terms of diagnostic accuracy and post-treatment prognosis. Methods: A total of 174 patients with ESCC were diagnosed as cT1b by endoscopic ultrasound (EUS) and white-light imaging between January 2008 and December 2014. Twenty-six patients diagnosed as cN+ by EUS or CT/PET were excluded. The diagnostic accuracy of invasion depth and lymph node metastasis was analyzed along with the post-treatment prognosis. Results: Initial treatment was ESD for 102 patients (ESD group) and surgery for 46 patients (surgery group). The histological diagnosis was T1a in 63 patients and T1b in 85 patients, meaning that 57.4% of the patients were accurately diagnosed. In the surgery group, 30 patients (65.2%) were accurately diagnosed as cN0. In the ESD group, 80 patients had an invasion depth of T1a-MM or deeper, which has a potential risk of metastasis. Additional surgery was performed for 15 patients, additional chemotherapy or chemoradiotherapy was performed for 43 patients, and follow-up without additional treatment was for 22 patients. Recurrence during follow-up was observed in 8 patients (lymph nodes in5 patients; other organs in 3 patients). Of the 16 patients with histological lymph node metastasis in the surgery group, 10 underwent adjuvant chemotherapy. Recurrence was noted in 3 patients (lymph nodes in 1 patient; other organs in2 patients). The mean follow-up period was 39 months for the ESD group and 45.8 months for the surgery group. Three- and five-year survival rates were respectively 93.1% and 79.3% in the ESD group and 89.8% and 85.1% in the surgery group, with no significant differences between the groups. Conclusions: Accuracy of preoperative diagnosis of invasion depth is still not high, which makes the ESD+α strategy an acceptable. As mid- to long-term outcomes were favorable in both groups, it appears that favorable outcomes can be obtained by performing multidisciplinary therapy based on the histological diagnosis.