The prognostic significance of in vitro bone marrow growth pattern in acute non-lymphocytic leukaemia.

The growth pattern of bone marrow cells in agar culture was studied in 56 patients with untreated acute non-lymphocytic leukaemia. 4 different growth patterns were recognized: (A) colony and cluster formation, (B) growth of small clusters (3-20 cells) only but less than 600/10(5) cells, (C) growth of small clusters only but more than 600/10(5) cells, and (D) no growth in vitro. Patients in group A and B had a significantly higher remission rate (23/34) than patients in group C and D (3/22). This was true also when only patients below 60 years of age were considered. The median survival time of patients in group A and B was 7.3 months and 9.4 months, and in group C and D 4.0 months and 3.3 months. Identical growth patterns were found for marrow and blood cells in 21 of 27 patients studied and the number of clusters in blood and marrow showed a significant correlation (r = +0.96, P less than 0.001). The mean 3H-labelling index (LI) of myeloblasts determined in 32 patients was 14.8 +/- 7.8% (SD). Patients with LI below 15% tended to have a higher remission rate than patients with LI above 15%. It is concluded that the in vitro growth pattern at diagnosis of bone marrow cells from patients with ANLL is of value in detecting patients with a poor response to current therapeutic protocols. Such information could possibly lead to alternative cytostatic regimes in these patients.