Reduced incidence of nodal micrometastasis after major response to neoadjuvant chemoradiation in locally advanced esophageal cancer

Background: Neoadjuvant treatment modalities for esophageal cancer were developed to improve local tumor control as well as to reduce lymph node metastases and distant metastases in patients with locally advanced esophageal cancer. The influence on nodal micrometastasis has not yet been evaluated. Methods: This study includes 52 patients with localized (cT2-4, Nx, M0) esophageal cancers (21 adenocarcinomas, 31 squamous cell cancers) who received neoadjuvant chemoradiation (36Gy, 5-FU, cisplatin) followed by transthoracic en bloc esophagectomy with two field lymphadenectomy. The extent of histomorphologic regression was categorized into major (< 10%) and minor response (>10% vital residual tumor cells) as recently reported. A total of 1186 lymph nodes were diagnosed as negative for metastases by routine histopathological analysis and were further examined for the presence of isolated tumor cells with the monoclonal anti-epithelial antibody AE1/AE3. Results: Twenty-two tumors (42.3%) showed a major histopathologic response whereas in 30 tumors (57.7%) only a minor response was present. Of 32 patients with a pN0 category, major response was present in 19 (59.4%) tumors, whereas 13 (40.6%) tumors showed minor response. Nine (69%) out of 13 patients with minor response had AE1/AE3-positive cells in their lymph nodes, whereas only four (21%) out of 19 pN0-patients with major response showed nodal micrometastasis (P = 0.013, chi(2)-test). Conclusions: If tumors show a major histomorphologic response following neoadjuvant chemoradiation, the presence of nodal micrometastasis is significantly reduced compared to those with minor response.