Late relapse in early-stage Hodgkin's disease patients enrolled on European Organization for Research and Treatment of Cancer protocols.

Abstract

The great majority of relapses after the treatment for early-stage Hodgkin's disease are observed within 4 to 5 years after treatment completion. This study describes the characteristics and outcome of patients who had late relapses, which was defined as relapses that occurred 5 or more years after initial treatment start. A total of 1,082 adult patients with early clinical stage Hodgkin's disease were enrolled on three consecutive European Organization for Research and Treatment of Cancer (EORTC) protocols (H1, H2, and H5 trials) from 1964 to 1981. Of these, 1,044 patients satisfied the eligibility criteria with a supradiaphragmatic localization, age greater than 15 years, and initial complete remission. Overall, 341 patients (32.6%) relapsed, 304 (29.1%) early and 37 (3.5%) late. For each of these 37 late relapsers, questionnaires were sent to the participating centers and detailed information for 34 relapses was obtained. Cumulative probabilities for developing a late relapse were estimated using the Kaplan and Meier method. Quantification of the relationship between late relapse and several confounding variables was performed using the Cox's proportional hazards model. The 10- and 15-year cumulative probabilities of late relapse in patients who were disease-free at 5 years were 4.8% and 8.3%, respectively. Patients treated on more recent protocols had a higher incidence of late relapse, possibly due to an attempt to tailor therapy to the specific prognostic factors (10-year cumulative probabilities, 4.6%, 2.6%, and 7.5% in trials H1, H2, and H5, respectively). Incidence of late relapses significantly correlated with male sex, B symptoms, mediastinal involvement, and treatment modality. Salvage treatment induced a complete response in 27 patients (79%) and a prolonged complete remission in 24 patients (71%). Twenty years after initial treatment start, similar overall survival rates were observed for late relapsing (72%) and nonrelapsing patients (75%). Late relapses of Hodgkin's disease are uncommon, but may be more frequent with recent protocols tailored to specific prognostic factors. If treated, their outcome is favorable. Late relapse is therefore another factor indicating that careful, long-term follow-up is needed for patients with Hodgkin's disease.