Sequential changes in the bone marrow trephine biopsy in B-cell chronic lymphocytic leukaemia

Trephine biopsy of the bone marrow is integral to both diagnosis and prognosis in B-cell lymphocytic leukaemia (B-CLL), but its usefulness would be enhanced by more information on the type, degree and rate of change that occur over time in histologic pattern and lymphocytic infiltration.

To investigate these changes by serial trephine biopsy in totally untreated patients, in treatment-free intervals in treated patients and during intervals of treatment.

In 82 patients with predominantly early B-CLL observed for a median of 65 months (13-331), 309 trephine biopsies were carried out, a median of three (two to eight) per patient. The biopsies were classified into nodular, interstitial, mixed and diffuse patterns. Lymphocytic infiltration was subjectively graded into minimal (< 20%), intermediate (20-50%) and majority (> 50%) categories and all changes were compared.

Intensity of infiltration increased through this histologic range, as did the relative risk of death. Survival of patients with > 50% involvement was significantly poorer than those with < 50%. Changes in both lymphocyte numbers and pattern occurred slowly in early disease but quickened as the leukaemia advanced. Under treatment, lymphocytes decreased but the histology did not alter significantly. Examining the marrow for disease progression should be part of regular follow-up. It may help identify the minority of patients with early disease which will run a more active course and in whom early therapy may yet be indicated. We recommend biopsy at two-yearly intervals in early disease, more frequently as the leukaemia advances. The minimal, intermediate and majority classification in addition to the histologic pattern is a useful grading.