Metastatic patterns and target organ arterial blood flow.

The frequency of metastatic involvement of eight 'target' organs from primary adenocarcinomas of the rectum and squamous cell carcinomas of the esophagus correlates significantly with target organ arterial blood flow (ml/min/g) when the primary cancers were in the upper third of the rectum or lower third of the esophagus, where the initial main venous drainage was into the portal system. When the primary cancers were located in other regions of these two organs where the initial main venous drainage was into the systemic venous system, this correlation was not seen. The results confirm that the 'hemodynamic' or 'mechanical' theory holds for two types of primary cancers in specific anatomic locations. In addition, they support the hypothesis that as yet unspecified interactions of cancer cells with the portal system, when this represents the initial main route for venous drainage, produce conformation with the 'hemodynamic' theory.