Chronic Myeloproliferative Disorders Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Polycythemia Vera
The Polycythemia Vera Study Group randomly assigned more than 400 patients to phlebotomy (target hematocrit <45), radioisotope phosphorous-32 (2.7 mg/m2 administered intravenously every 12 weeks as needed), or chlorambucil (10 mg administered by mouth daily for 6 weeks, then given daily on alternate months). The median survival for the phlebotomy group (13.9 years) and the radioisotope phosphorous-32 group (11.8 years) was significantly better than that of the chlorambucil group (8.9 years), primarily because of excessive late deaths from leukemia or other hematologic malignancies.[Level of evidence: 1iiA] Because of these concerns, many clinicians use hydroxyurea for patients who require cytoreductive therapy that is caused by massive splenomegaly, a high phlebotomy requirement, or excessive thrombocytosis.
In a pooled analysis of 16 different trials, interferon-alpha therapy resulted in avoidance of phlebotomy in 50% of patients, with 80% of patients experiencing marked reduction of splenomegaly.[Level of evidence: 3iiiDiv] Interferon posed problems of cost, side effects, and parenteral route of administration, but no cases of acute leukemia were seen in this analysis. When patients are poorly compliant with phlebotomy or issues of massive splenomegaly, leukocytosis, or thrombocytosis supervene, treatment with interferon or pegylated interferon is considered for patients younger than 50 years (who are more likely to tolerate the side effects and benefit from a lack of transformation to leukemia), while hydroxyurea is considered for patients older than 50 years.[2,14]
In a Cochrane review of two randomized studies of 630 patients with no clear indication or contraindication for aspirin, those receiving 100 mg of aspirin versus placebo had reduction of fatal thrombotic events, but this benefit was not statistically significant (odds ratio, 0.20; 95% CI, .03–1.14). A retrospective review of 105 patients who underwent surgery documented 8% thromboembolism and 7% major hemorrhage with prior cytoreduction by phlebotomy and postoperative subcutaneous heparin in one half of the patients.
Guidelines based on anecdotal reports have been developed for the management of pregnant patients with p. vera.
- Hydroxyurea (alone or with phlebotomy).[11,12]
- Interferon-alpha [13,17,18] and pegylated interferon-alpha.
- Rarely, chlorambucil or busulfan may be required, especially if interferon or hydroxyurea are not tolerated, as is often seen in patients older than 70 years.
- Low-dose aspirin (≤100 mg) daily, unless contraindicated by major bleeding or gastric intolerance.[8,15]