Proliferation and Cancer Metastasis from the Clinical Point of View

Abstract

Lymph node metastases result from specifically lymphotrophic metastatic cells that may have no capacity to grow in vital organs, i.e., brain, liver, lung. Thus, lymph node metastases are predictors, not governors, of overall survival since they do not control survival. This is demonstrated by randomized trials, literature reviews, and meta-analyses of epithelial cancers which show no survival advantage comparing various types of nodal resection, or even observation only. Metastatic lymph nodes demonstrate the primary cancer’s capacity to shed and disperse cells, but these shed cells display organ-specific spread. Thus, liver and lung resections for oligo-metastases cure patients because their metastatic cells may not involve other organs. Even extensive nodal metastases, by themselves, do not cause death, whereas extensive liver, lung, or brain metastases kill their host. Lymph node specificity is displayed in low-risk differentiated thyroid cancer, where 75% of patients have node metastases, yet have a 99% 20-year survival. Adjacent nodal metastases are removed in cancer surgery and become a prognostic marker, whereas other distant organs are not sampled as carefully, but also may harbor metastatic cells which could be prognostic markers if discovered. Genetic analysis of cancers predicts detailed biologic behavior that is more accurate than node metastases or size or grade, and will soon displace nodes as the most important prognostic marker, thus removing the necessity of removing lymph nodes.