The prognostic implication of clinical and histological features in Ph1+ chronic myelocytic leukaemia (CML)

A study on clinical and histological features of prognostic significance was performed in 45 patients with Ph1+ -CML who showed median survival of 36 months. The histological features were evaluated by morphometry of iliac crest biopsies. Among the variables correlated with prognosis, we eliminated those without primary importance by mutual univariate retrospective stratification. Thus a clinical and a histological set of important prognostic criteria was established. Their influence on prognosis proved to be independent of each other and therefore could be used for separate classifications. Clinical classification yielded two groups with different prognosis: compared to the rest of the patients, the prognosis was much worse for those with a spleen size greater than 10 cm, a liver size greater than 2 cm (below costal margin) and greater than 5% circulating blasts plus promyelocytes. The histomorphological classification consisted of three subgroups: a better than average prognosis was found for patients with pseudo-Gaucher cells in the bone marrow, while in the remaining cases the prognosis was worse in patients with a high number of megakaryocytes (greater than 70/mm2) and a low volume ratio of granulopoiesis: megakaryocytes (less than 15). Since liver size was correlated with the duration of prediagnostic symptoms, the clinical classification probably reflects different disease stages, i.e. a later CML diagnosis. However, the histological set of prognostic factors is independent of the length of the prediagnostic period. Consequently, this morphological classification seems to discriminate different subgroups. Another important prognostic factor, marrow fibrosis, was independent of other histomorphological features, and correlated with duration of symptoms. It obviously also indicates more advanced disease.