Background/aims: The term "micrometastases" has been confused in many aspects. While the influence of lymph node metastases in esophageal and colorectal cancer is well known, the presence and importance of micrometastases is under debate. We investigated micro lymph node invasion in two different kinds of digestive tumors with very high mortality, and identified its possible repercussion on patient survival.
Methodology: Lymph nodes of two groups of patients N0 on routine histopathology after radical resection (R0): 21 with esophageal carcinoma (Group I), and 21 with colorectal carcinoma (Group II), were studied by immunohistochemistry using monoclonal antibodies directed against cytokeratins of wide spectrum. The results were classified as positive or negative and compared with patient survival.
Results: Five of twenty-one (5/21) patients in group I and eight of twenty-one (8/21) in group II were positive for micrometastases. Median survival time in the positive esophageal group was 9.5 months vs. 68 in the negative one (p=0.16). Median survival time in the positive subset colorectal group was 54.5 months vs. 76.8 in the negative subgroup (p=0.5). Our results did not show statistical differences in survival time between patients positive or negative for micrometastases; however it is evident, especially in the esophageal cancer group, that there is a negative tendency of positive micrometastases on survival time.
Conclusions: The presence of micrometastases in lymph nodes of patients N0 after conventional histopathology is frequent. Our preliminary results did not allow definitive conclusions but we may suppose its negative influence on patient survival.