The relevance of reticulin stain‐measured fibrosis at diagnosis in chronic myelogenous leukemia

Although collagen myelofibrosis indicates poor prognosis in late stages of chronic myelogenous leukemia, the significance of reticulin stain‐measured fibrosis in newly diagnosed patients is unknown. One hundred and thirty‐eight patients with untreated or minimally treated chronic phase Philadelphia chromosome‐positive chronic myelogenous leukemia had reticulin stain studies made on their bone marrows at diagnosis. Reticulin fibrosis was graded on a scale of 1 to 4. Significant (Grade 3 or 4) fibrosis was noted in 65 patients (47%). Compared with patients with mild (Grade 1 to 2) reticulin fibrosis, those with significant fibrosis had a higher incidence of splenomegaly ≥10 cm (29% versus 49%; P = 0.02), hemoglobin <10 g/dl (19% versus 49%; P <0.01), weight loss ≥6.75 kg (10% versus 30%; P = 0.11), marrow blasts ≥5% (7% versus 28%; P <0.01), peripheral blasts ≥3% (30% versus 46%; P = 0.09), and additional karyotypic abnormalities (1% versus 17%; P < 0.01). The incidence of thrombocytosis was similar in the two groups. Prognostically, median survival was significantly shorter for the 26 patients with Grade 4, compared with the 39 patients with Grade 3, and the 73 patients with Grade 1 or 2 reticulin fibrosis (32 versus 49 versus 57 months; P = 0.03). Reticulin fibrosis is a useful biologic and prognostic index in newly diagnosed patients with chronic phase chronic myelogenous leukemia.