Cell kinetics of solid tumors with time and its clinical implication.

The proliferative rate has been evaluated for several human tumor types as the fraction of cells in S-phase. The methodologies most often used are autoradiographic determination of 3H-thymidine incorporation and flow cytometric evaluation of DNA content. Cell kinetics determined on various solid primary tumors at the time of diagnosis is not related to pathologic stage but it is an indicator of clinical evolution of the disease similar or superior to other biologic and pathologic prognostic factors. In early disease, submitted to loco-regional treatment as a first-line therapy, the rate of cell proliferation provides prognostic information on relapse-free and overall survival. In this clinical situation, a different metastatic potential can be attributed to tumors with different proliferative rates. In more extensive disease, submitted to systemic treatment, proliferation indices generally influence overall survival, eventhough in responsive tumors a fast proliferative activity could be indicative of higher aggressiveness and remarkable chemosensitiveness. Proliferation indices of the metachronous metastatic lesions is increased over those of the primary tumors as a further evidence of the association between proliferative activity and disease progression.