Reproducibility and prognostic value of different non-Hodgkin's lymphoma classifications: study based on the clinicopathologic relations found in the EORTC trial (20751).

In the EORTC trial 20751, six pathologists belonging to five different centers classified tumoral lymph nodes from 406 untreated patients with non-Hodgkin's lymphoma (NHL) into three different NHL classifications. NHL were most easily and reliably subdivided according to the growth pattern (the rate of consensus being 93%). Classification according to growth pattern proved to be of prognostic significance. The rate of consensus of classifying cases in the different NHL classifications ranged from 74% for the Rappaport, through 70% for the Kiel to 67% for the international working formulation. It is concluded that NHL are reliably classified according to their growth pattern, and that this subdivision is of primary prognostic significance.