Prognostic significance of DNA-analysis by flow cytometry in non-Hodgkin's lymphoma

DNA analysis by flow cytometry was performed on lymph node cells obtained from 65 untreated patients with non-Hodgkin's lymphoma. According to the Kiel classification 41 cases were of low grade malignancy and 24 cases belonged to the high grade malignancy group. 47 out of 61 evaluable cases were diploid/near-diploid, 12 were aneuploid and 2 cases showed polyploidy. No difference in survival was found between diploid/near-diploid and aneuploid cases. The percentage of S-phase cells was found to be a valuable prognostic parameter. Using a cut point at 4 per cent S-phase cells between low and high S-phase lymphomas a highly significant difference in survival was demonstrated (p = 0.0004). The actuarial survival up to 3 years was about 77 per cent for lymphomas with less than 4 per cent S-phase cells to be compared with 20 per cent for patients with high S-phase (greater than or equal to 4 per cent) lymphomas. Subdivision according to the percentage of S-phase cells seemed to be a better prognostic predictor than morphologic subclassification.