Abstract
In 18 untreated adult patients (median age 62.5 yr) with advanced non‐Hodgkin's lymphoma of unfavourable histology, thymidine labelling indices (LIs) of the lymphoma cells were assessed. The patients were treated with combination chemotherapy and have been followed for 29–60 (median 52) months or until death. The survival curve had a steep fall during the first 2 yr. Between 2–5 yr after treatment there was a flattening of the curve and survival seemed to be similar to the survival expected for a Swedish population matched for age and sex. 11 patients died with 2 yr and 7 patients have survived for a longer period. Age, histopathologic classification and clinical stages were comparable in short‐term and long‐term survivors and treatment was not more aggressive for the long‐term survivors. The LIs were significantly higher (median 8.2) in short‐term survivors than in the long‐term survivors (median 1.4). Long‐term survival following combination chemotherapy of advanced NHL of unfavourable histology seems to be achieved mainly in patients with a low proliferative activity of the lymphoma cells. It is suggested that in NHL a high proliferative activity may facilitate the generation of new mutants and that some of these are spontaneously resistant to various chemotherapeutic drugs.