LONG-TERM SURVIVAL AFTER HISTOLOGIC TRANSFORMATION OF LOW-GRADE FOLLICULAR LYMPHOMA

Purpose: To describe the course of patients following histologic trans formation (HT) from low-grade follicular lymphoma to intermediate- or high-grade non-Hodgkin's lymphoma. Patients and Methods: Patients were identified from data bases in the Division of Oncology and the Deport ment of Surgical Pathology. HT was defined as the conversion of a foll icular small cleaved-cell or follicular mixed small cleaved-cell and l arge-cell lymphoma to a diffuse large-cell, diffuse mixed small cleave d-cell and large-cell or any high-grade lymphoma. Results: We analyzed the clinical course of 74 low-grade lymphoma patients with histologic ally proven transformation occurring from 1965 to 1988. The median tim e from diagnosis to HT was 66 months, acid the median age at HT was 58 years. The median duration of survival after transformation was 22 mo nths. Anatomic extent of disease at HT (limited v extensive, P = .01), prior chemotherapy (none v any, P = .01), and response to therapy (co mplete v partial or none, P = .005) at time of HT were identified as s ignificant predictors of survival after HT in backward-selection Cox r egression analysis. Thirty patients attained a complete response to th erapy at HT. They had a median survival duration of 81 months after HT . Conclusion: A subset of patients with HT from low-grade follicular l ymphoma to intermediate- or high-grade lymphoma enjoys relatively long -term survival, Patients with limited disease and no previous exposure to chemotherapy have the most favorable prognosis,