Hairy cell leukemia: a retrospective study of 235 cases by the Italian Cooperative Group (ICGHCL) according to Jansen's clinical staging system.

This is a report from a cooperative study on hairy cell leukemia (HCL) involving 20 Hematology Departments in Italy. Data for the patients was collected between January 1967 and December 1981 and included 235 cases of which 203 could be evaluated; 160 were males (78.8%) and 43 females (21.2%) with an M:F ratio of about 3:1; mean age was 54 years (range 26-82 yrs). The diagnostic criteria of admission were: typical aspect of hairy cells, in peripheral blood and bone marrow smears, tartrate resistant acid phosphatase (TRAP) positivity, typical bone marrow, spleen, liver and/or lymph node histology, and/or electronmicroscopy. On the basis of hemoglobin level and spleen size at the time of diagnosis, three stages could be distinguished according to Jansen: 51 patients, 27 of which splenectomized, were in stage I; 67 patients, of which 44 splenectomized, were in stage II; 85 patients of which 60 splenectomized, were in stage III. The actuarial survival curves of these patients showed clear distinction between the three stages. In the first stage the difference in survival, between splenectomized and nonsplenectomized groups, was not statistically significant (p less than 0.5): on the contrary, in stages II and III the difference in survival was statistically significant (stages II and III; p less than 0.01).