The natural history of low grade non-Hodgkin's lymphoma and the impact of a no initial treatment policy on survival.

The natural history of low grade lymphoma and the influence of a 'no initial treatment' policy on survival were studied retrospectively in a group of 153 patients with stage II-IV low grade non-Hodgkin's lymphoma. The median follow-up was 85 months (range 45-229 months) and median survival of 50 months (range 14-220 months). Favourable outcome was significantly associated with the absence of B symptoms and a centroblastic/centrocytic (cb/cc) diffuse and follicular histological subtype and was inversely associated with increasing age. No significant differences in survival were found according to patient gender, site or stage of disease or whether the patients were participants in a clinical trial. Importantly, there was no survival disadvantage amongst the 56 patients who were initially untreated compared to those receiving other treatment modalities: initially untreated patients had a median survival of 75 months; 56 per cent were alive at 5 years and the median treatment free interval was 33 months. This favourable outcome persisted even after adjustment for other important prognostic variables. Further studies are needed to identify the characteristics of those patients with indolent disease in whom treatment may be deferred without adversely affecting survival.