Non-Hodgkin's lymphoma after primary Hodgkin's disease in the German Hodgkin's Lymphoma Study Group: incidence, treatment, and prognosis.

Abstract

The cumulative incidence for non-Hodgkin lymphoma's (NHL) after primary Hodgkin's disease (HD) ranges between 1% and 6%. To investigate the course of disease for secondary NHL, we retrospectively analyzed patients treated within clinical trials of the German Hodgkin's Lymphoma Study Group (GHSG) since 1981. From 1981 to 1998, the GHSG conducted three generations of clinical trials for the treatment of primary HD involving a total of 5,406 patients. Reference histology by an expert panel was obtained for 4,104 of the patients. Data on incidence, treatment, and outcome of secondary NHL were updated in March 1999. At first diagnosis of HD, the pathologists rejected 114 (2.1%) of 5,520 cases initially diagnosed as HD and rediagnosed them as primary NHL. Fifty-two (0.9%) of the remaining 5,406 patients developed a secondary NHL. One patient was excluded from further analyses because of insufficient documentation. Six patients had no further therapy because of patient refusal (n = 1) or rapidly progressive disease (n = 5). For the remaining 45 patients, overall response rate was 43% (36% complete response and 7% partial response). The actuarial 2-year freedom from treatment failure (FFTF) and overall survival (OS) for all patients was 24% and 30%, respectively, and for patients with diffuse large-cell lymphoma, it was 28% and 35%, respectively. Time of occurrence of secondary NHL after first diagnosis of HD and variables employed in the age-adjusted International Prognostic Factor Index (IPFI) significantly influenced treatment outcome. In the GHSG, the incidence of secondary NHL with 0.9% is relatively low compared with previously reported series. The prognosis of secondary NHL seems dismal and is significantly influenced by time of occurrence and the age-adjusted IPFI. In a subset of patients with secondary NHL, long-term disease-free survival could be achieved.