**5. Lymph node metastasis along the recurrent laryngeal nerve**

Extensive lymphadenectomy with esophagectomy for esophageal carcinoma improves the prognosis in Japan. In particular, lymph nodes along the RLN are considered as significantly important lymph nodes those are recommended to be completely dissected. However, lymph node along the RLN dissection complicates high morbidity and mortality. Udagawa et al. showed lymph node metastasis along the rt. RLN and cervical paraesophageal at a rate of 31.9, 22.2%, 19, 13.9%, and 14.7, 12.4% of upper, middle, and lower thoracic esophagus, respectively. Lymph node metastasis along the lt. RLN and cervical paraesophageal was found at a rate of 19.1, 20.1%, 14.1, 8.3%, and 8.1, 5% of upper, middle, and lower thoracic esophagus in Japan, respectively [2]. Ye et al. reported that the recurrent laryngeal nerve lymph node metastasis from esophageal carcinoma is detected at the rate of 34.2% in China [21]. Lymph node metastasis along the recurrent laryngeal nerve was detected, and the rate of lymph node metastasis was 23.4%. The rate of rt. RLN lymph node metastasis was 20.8%, which was slightly higher than the rate of lt. RLN lymph node metastasis which had a rate of 15.8%.

#### **5.1. ESCC**

In ESCC, lymph node metastasis is possible to occur in the neck, mediastinum, and abdomen. The location of RLN lymph node is from the upper mediastinum and to the cervical region, where lymph node metastasis is frequently detected in thoracic ESCC. Early, initial and micro metastasis of ESCC often occur and RLN lymph node metastasis has been regarded as an indication for three-field lymphadenectomy in the surgical treatment of ESCC. More importantly, RLN metastasis has been shown to be a strong predictor of poor prognosis in ESCC.

There are many reports about lymph node metastasis along the recurrent laryngeal nerve in Asia. In Japan, Igaki et al. reported that cervical or celiac lymph node metastasis in patients with carcinomas of the lower thoracic esophagus should be distinguished from pathologic M1 status in the UICC-TNM staging system [1].

#### **5.2. EAC**

Giacopuzzi et al. reported that in Siewert type I tumors, when standard mediastinal lymphadenectomy is performed, about half of the node-positive patients show positive nodes in mediastinal stations [22]. Specifically, upper and mid mediastinal lymph node metastases (right paratracheal, subcarinal, aortopulmonary window) were reported in up to 25% of patients. When the few studies in which cervical nodes are also removed are considered, a non-negligible incidence of metastases is detectable, but, due to the scarcity of available data and the higher complication rate of three-field dissection, this is not currently thought to be relevant in clinical practice. Mediastinal nodes are involved in about 30% of Siewert type II cases. Although most of the positive nodes occur at lower stations, the rate of metastasis detected in the upper-mid mediastinum after transthoracic esophagectomy ranges between 8 and 22% [22].
