Morphological and clinical significance of cell kinetics in non-Hodgkin's lymphomas.

The relation between the proliferative activity and morphologic features according to Rappaport and Kiel classifications and the Working Formulation (WF) was analyzed in a series of 123 adult patients with non-Hodgkin lymphomas. Cell kinetics was determined as in vitro 3H-thymidine labelling index (LI). A significant association was observed between low LI and follicular histology or low grade of the WF, as well as between high LI and high-grade of malignancy of the Kiel and WF. The analysis of the clinical relevance of cell kinetics on objective response to treatment showed a higher frequency (91%) of complete remission in the tumors with low proliferative activity versus tumors with high proliferative activity (48%) (p = 0.00003). Moreover, cell kinetics proved to be and important indicator of 6-year survival on the whole population of patients (66% for slowly vs 18% for fast-proliferating tumors; p less than 10(-9)) and a further discriminant within diffuse histology (68% vs 9%; p less than 0.0001), low-grade malignancy according to the Kiel (64% vs 15%; p less than 10(-8)) and low (64% vs 28%; p less than 0.005) and intermediate grades of the WF (68% vs 9%; p less than 0.0001).