Strong Impact of Micrometastatic Tumor Cell Load in Patients with Esophageal Carcinoma

To assess the role of immunohistochemically detectable nodal microinvolvement of patients with "curatively" resected esophageal carcinoma. In 73 patients with resectable esophageal carcinoma [squamous cell carcinoma (SCC), n = 45 (61.6%); adenocarcinoma (AC), n = 28 (38.4%)] a total of 2174 lymph nodes (LN) were removed. In each of the 1958 LN classified as negative on conventional histopathology, immunohistochemistry was performed using the anticytokeratin antibody AE1/AE3. To determine the role of the amount of residual tumor load, the patients were grouped according to the percentage of LN affected with micrometastasis (0%, < 11%, and a parts per thousand yen11%). Tumor cells were immunohistochemically detected in 47 LN (2.4%) from 25 (34.2%) patients. Five-year overall survival probability (5-YSP) of 30% in pN(0) patients with detected occult tumor cells in LN was significantly worse than that in those without nodal microinvolvement (76%, P = 0.021), hereby resembling that of pN1-patients (24%, P = 0.84). Median overall survival in patients with no (0%), low (< 11%), and high (> 11%) micrometastatic tumor load was 43, 27, and 11 months, respectively. Substratification according to histological type showed that, in patients with AC, the presence of nodal microinvolvement had a significant impact on 5-YSP (0% versus 65%; P = 0.03), whereas in patients with SCC, differences of 5-YSP were only of borderline significance (24% versus 53%; P = 0.081). Minimal tumor cell load as assessed by the ratio of micrometastatically affected LN is a complementary tool for better risk stratification of patients with esophageal carcinoma.