Background and study aims: The application of endoscopic mucosectomy in early esophageal cancer is limited by the presence of lymph-node metastasis. The aim of this prospective study was to analyze the rate of lymph-node involvement relative to the depth of mucosal or submucosal tumor penetration, comparing squamous-cell carcinomas and adenocarcinomas.
Patients and methods: A total of 60 patients with pT1 esophageal cancer--24 with squamous-cell carcinomas (SCCs) and 36 with adenocarcinomas--were treated with transthoracic en-bloc esophagectomy with two-field lymphadenectomy (n = 50) or transhiatal esophageal resection (n = 10). An average of 30 lymph nodes were examined, and the following characteristics were evaluated: histology, mucosal infiltration, depth of submucosal wall infiltration in three thirds (sm1, sm2, sm3), grading, resection category, ratio of metastatic to resected lymph nodes, and locations of metastatic nodes.
Results: The rates of lymph-node metastasis were 0% for the 16 mucosal carcinomas and 45% for the 44 submucosal carcinomas (P < 0.01). There were no significant differences in the extent of lymph-node involvement between submucosal adenocarcinomas (41%) and submucosal SCCs (50%). Sm1 carcinomas were associated with a lower rate of lymph-node metastasis (SCCs 33%, adenocarcinomas 22%) than sm3 carcinomas (SCCs 69%, adenocarcinomas 78%). Two patients (9%) with submucosal SCCs and five patients (23%) with submucosal adenocarcinomas were classified as having stage pM1 lymph. The average lymph-node ratio in patients with pN1 was 0.13 for adenocarcinomas and 0.1 for SCCs (difference not significant). In the multivariate analysis, the parameters mucosal vs. submucosal (P < 0.01) and G1/G2 vs. G3 (P < 0.05) showed a significant impact in relation to metastatic lymph nodes.
Conclusions: The most important factor for predicting lymph-node metastasis in early esophageal cancer is the presence of submucosal infiltration. Early adenocarcinomas and SCCs do not differ with regard to their rate of lymphatic involvement. The rate of lymph-node metastasis increases with the depth of submucosal infiltration, but metastases can already occur in sm1 lesions. Submucosal infiltration is a contraindication for endoscopic mucosectomy. Limited surgical procedures without adequate lymphadenectomy do not appear to be appropriate in the treatment of patients with submucosal esophageal carcinomas.