PROGNOSTIC VALUE OF CELLULAR PROLIFERATION AND HISTOLOGIC GRADE IN FOLLICULAR LYMPHOMA

The clinical usefulness of histologic grading in follicular lymphoma ( FL) is controversial and is further compromised by the subjective natu re and poor reproducibility of most systems in current use. Therefore, we decided to objectively evaluate the importance of cellular prolife ration in FL, along with the current grading systems. We studied 106 p atients with FL who were uniformly staged and aggressively treated. A proliferative index (PI) was determined quantitatively using an automa ted image analyzer and a new Ki-67 antibody that stains archival paraf fin tissues. The cases were also subclassified according to the Berard , Rappaport, Luke-Collins, and Jaffe methods, and survival analysis wa s performed. Patients with a low PI (<40%) had a significantly longer overall survival (OS) than those with a high PI (greater than or equal to 40%). but the PI did not predict failure-free survival (FFS). The mean PI correlated well with the subgroups in each of the various clas sifications. All four of the classification methods were predictive of OS, but only the Berard method appeared to predict FFS and suggest th at a proportion of patients with FL may be curable. In multivariate an alysis. histologic classification was the only independent predictor o f OS (Berard method: relative risk, 3.1) and the International Prognos tic Index was the only independent predictor of FFS (relative risk, 2. 3). We conclude that the Berard method for grading of FL is clinically useful and, along with the International Prognostic Index, should be included in future clinical studies of FL. The measurement of cellular proliferation does not appear to add additional useful information in FL. (C) 1995 by The American Society of Hematology.