Prognostic Implications of Abdominal Computed Tomography at Diagnosis in Patients with Polycythemia Vera or Essential Thrombocythemia

Background: To our knowledge, no reports have examined the clinical significance of splenomegaly measured using computed tomography (CT) in patients with polycythemia vera (PV) or essential thrombocythemia (ET). This study retrospectively analyzed abdominal CT in PV and ET patients to determine the prognostic role of splenomegaly on CT at diagnosis.

Methods: This study enrolled patients who were newly diagnosed with PV or ET between 2005 and 2014 at Chungnam National University Hospital. Spleen volume was estimated by measuring the caudocranial dimension and maximum size and thickness in the axial plane on cross-sectional images (Prassopoulos et al. Eur Radiol 1997;7(2):246-8).

Results: In total, 46 patients were diagnosed with PV and 73 with ET; abdominal CT was performed at diagnosis in 38 (82.6%) PV patients and 45 (61.6%) ET patients. The International Working Group for Myeloproliferative Neorplams Research and Treament (IWG-MRT) risk score and International Prognostic Score for ET (IPSET) were well applied to these patients group. In the PV group, there were no significant differences in clinical features or laboratory findings between patients who did or did not undergo CT. In the ET group, patients who underwent abdominal CT had lower hemoglobin and hematocrit levels, and were less likely to have a history of thrombosis than those who did not. Splenomegaly was observed in 29 (73.7%) patients with PV and 18 (40.0%) patients with ET. Splenomegaly greater than twice the normal value was observed in 11 (28.9%) PV patients and 4 (8.9%) ET patients. In the PV group, patients with splenomegaly on CT had significantly higher leukocyte and lactate dehydrogenase (LDH) levels than patients without splenomegaly. Splenomegaly more than twice the normal value were not observed in PV patients over 67 years old; in younger patients, PV patients with splenomegaly greater than twice the normal value had lower overall survival than those with smaller spleens (p = 0.02). In the ET group, patients with splenomegaly on CT had higher hemoglobin, hematocrit, leukocyte, and LDH levels than did patients without splenomegaly, but there was no difference in their overall survival (p = 0.643).

Conclusion: These results indicate that splenomegaly measured by abdominal CT might be useful for predicting prognosis in patients with PV.