Flow cytometric DNA analysis: a prognostic tool in non-Hodgkin's lymphoma.

Surgical biopsies from 234 untreated patients with non-Hodgkin's lymphoma (NHL), classified according to the Kiel nomenclature, were analysed with respect to proliferative activity (S-phase) and DNA content by flow cytofluorometric (FCF-DNA) analysis. The percentage of cells in S-phase was significantly higher in lymphomas of high compared to low grade NHL (p less than 0.001). Patients with lymphomas of high grade histology and low S-phase values (less than 5.6%) achieved complete remission (CR) more often (p less than 0.05) and survived significantly longer than those with high S-phase values (p less than 0.05). In the low grade NHL group the S-phase value did not correlate to response. S-phase correlated to survival for patients with the lymphocytic (CLL & IC) (p less than 0.05) and follicle center cell (FCC) derived (p less than 0.01) but not in blastic (LB, IB, Burkitt) NHL. DNA-aneuploidy was associated with poor response to therapy and shorter CR duration in low grade NHL (p less than 0.05 for both). However, the degree of DNA-ploidy (neardiploid or aneuploid) did not correlate to survival in any of the NHL groups analysed (high- or low grade, lymphocytic, FCC derived or blastic). The Cox regression analysis indicated that the S-phase value was a stronger predictor of survival than histopathology, stage or age, especially in low grade NHL. These results suggest that S-phase analysis should be included in the clinical evaluation of NHL patients as a prognostic indicator.