Arora, Brijesh

Abstract Background: Previously established adverse prognostic factors in myelofibrosis with myeloid metaplasia (MMM) include anemia (hemoglobin < 10 g/dL), leukocytosis or leukopenia, presence of circulating blasts, and hypercatabolic symptoms (Dupriez et al. 1996;88:1013, Cervantes et al. BJH1998;102:684). Measurement of peripheral blood (PB) CD34 count has been shown to have diagnostic as well as possible prognostic value in MMM (Barosi et al. Blood2001;98:3249). Methods: A concurrent evaluation of PB CD34 count, bone marrow histology, and other clinical and laboratory parameters was conducted in a consecutive cohort of both newly and previously diagnosed patients with MMM. The study patients were prospectively followed for a minimum of 3 years in order to determine the prognostic value of PB CD34 count on survival, leukemic transformation, and disease progression from the time of PB CD34 analysis. Results: i. Patient cohort: A total of 94 patients (median age 61 years, range 26–81; 61 males) were accrued between January 2000 and August 2001 and subsequently followed through July 2004. MMM subtypes included agnogenic myeloid metaplasia (AMM; 58 patients), post-polycythemic myeloid metaplasia (PPMM; 12 patients), post-thrombocythemic myeloid metaplasia (PTMM; 12 patients), cellular phase MMM (8 patients) and hypocellular variant MMM (4 patients). At the time of study entry, 19 patients (20%) were newly diagnosed and 75 were established cases (median of 36 months from initial diagnosis, range 4–221). The Dupriez prognostic scores were 0 in 37 (39%), 1 in 37 (39%), and 2 in 20 patients (21%). ii) Clinical correlates of PB CD34 count: The median PB CD34 count for the entire study cohort was 54.7 x 106/L (range 0–5345) with 85% patients having increased values (> 5 x 106/L). Cellular phase MMM and PPMM had significantly lower PB CD34 counts compared to the other MMM subtypes. On univariate analysis, PB CD34 count significantly correlated with Dupriez prognostic score, leukocyte count, circulating blast or immature myeloid cell percentage, and presence of hypercatabolic symptoms but not with age, gender, anemia (hemoglobin < 10 g/dL), abnormal cytogenetics, disease duration, treatment history, splenectomy status, nucleated RBC count (NRBC), platelet count, or bone marrow histology including fibrosis, osteosclerosis, and angiogenesis. On multivariate analysis, only leukocyte count and PB blast or immature myeloid cell percentage retained their significance. iii) Prognostic evaluation of PB CD34 count : As of July 16, 2004, 43 patients (46%) have died and median duration of follow up in the surviving patients was 41 months (range 36–54). The projected overall survival at 5 years was 50%. On Cox proportional regression analysis, individual variables that correlated with inferior survival included anemia (hemoglobin < 10 g/dL), advanced age, presence of hypercatabolic symptoms, abnormal cytogenetics, and increased leukocyte count, circulating blast percentage, Dupriez prognostic score, and NRBC. PB CD34 count displayed borderline significance (p=0.06). However, on multivariate analysis, only anemia, leukocytosis, and age retained prognostic significance. Similarly, PB CD34 count did not predict either subsequent leukemic transformation or disease progression. Conclusion: PB CD34 count is often but not always increased in MMM and correlates significantly with leukocytosis and degree of PB myeloid immaturity. The current prospective study does not support an independent prognostic value for PB CD34 count in MMM.

Abstract Background : Thirty to 50% of patients with myelofibrosis with myeloid metaplasia display detectable bone marrow cytogenetic abnormalities at diagnosis with some(Demory et al. Blood1988;72:855, Dupriez et al. Blood1996;88:1013, Reilly et al. BJH1997;98:96) but not other studies (Cervantes et al. BJH1998;102:684, Okamura et al. Int J Hematol2001;73:194) suggesting a detrimental effect on survival. Methods : The current prospective study was conducted as a follow-up of the observations from an antecedent retrospective study that identified sole abnormalities of either 13q- or 20q- as ‘favorable’ to survival (Tefferi et al. BJH2001;113:763). All clinical and laboratory measurements, including bone marrow examination and karyotype analysis, were performed concurrently in consecutive cases of histologically confirmed MMM regardless of either duration of disease or presence of active therapy. Survival, leukemic transformation rate, and clinical progression were determined from the time of cytogenetic analysis. Results : Karyotypic analysis was successfully performed in a total of 88 patients (median age 61 years; 31 females) and the results were normal in 49 (56%) and abnormal in the remaining 39 patients with 9 (10%) displaying ‘favorable’, and 30 (34%) ‘other’ clonal abnormalities. At the time of study entry, 57 patients were not recieving any form of therapy, 18 were newly diagnosed, and the Dupriez prognostic score distributions were ‘0’ in 33 patients, ‘1’ in 35 and ‘2’ in 20 (Dupriez et al. Blood1996;88:1013). All patients were followed for a minimum of 3 years and a median of 42 months. The 3 cytogenetic categories were similar in age and gender distribution. Survival in the favorable cytogenetic group was similar to that of the normal group and significantly better than the group with other cytogenetic abnormalities (p=0.02). Figure Figure Similarly, no patient (0%) in the ‘favorable’ group transformed into acute leukemia while 6 of 30 (20%) in the ‘other’ and 5 of 49 (10%) in the normal groups did (p=0.21). In a Cox regression analysis, cytogenetic lesions other than the ‘favorable’ kind, hemoglobin below 10 g/dL, leukocytosis, hypercatabolic symptoms, increased blood blast %, blood CD 34 count above 100 x 106/L were individually associated with shortened survival. In a multivariate analysis, only hemoglobin level and leukocyte count retained their significance. Conclusion : Single chromosomal abnormalities of either 13q- or 20q- should be considered as ‘favorable’ cytogenetic lesions in MMM while other abnormalities are associated with an adverse prognosis. The current observation explains the discrepancy in the literature regarding the prognostic relevance of cytogenetic findings in MMM and warrants additional studies to determine the value of incorporating the specific information in prognostic scoring systems.