Response, complications and risk of leukemic transformation of phosphorus-32p treatment in philadelphia-negative chronic myeloproliferative syndromes

Objective

Describe our experience in treatment with Phosphorus-32P for refractory Philadelphia negative chronic myeloproliferative syndromes or with side effects to the usual treatment, its complications and risk of leukemic transformation.

Material and methods

Retrospective descriptive study including 17 patients with a diagnosis of Philadelphia-negative chronic myeloproliferative syndrome treated with Phosphorus-32P in our hospital from January 1985 to March 2017. Indications, response to treatment, as well as early and late complications have been analyzed.

Results

Of the 17 patients treated with 32P (11 men, 6 women; mean age 79,8 years), 6 patients had Polycythemia Vera and 11 Essential Thrombocytosis. A single dose was administered in 9 of the subjects, the rest required two or more doses due to inadequate hematological response and/or relapse. The total dose range of Phosphorus-32P administered was 116−951 MBq (median: 236 MBq). In 14 patients treated with Phosphorus-32P, complete or partial response was achieved in hematimetry. In 11 patients, the response was complete, established as a platelet count <400.000/mm³ in those diagnosed with Essential Thrombocythemia and a hematocrit <45% in cases of Polycythemia Vera. The median follow-up of patients from the date of the first treatment of Phosphorus-32P until study completion or death was 37 months (range: 5–230 months). Regarding early complications, 2 cases of anemia requiring blood transfusion were observed, and 1 case of mild thrombocytopenia. No leukemic transformation was identified.

Conclusions

In our experience, treatment with Phosphorus-32P has been a useful therapeutic option in Philadelphia-negative chronic myeloproliferative syndromes in elderly patients who showed poor tolerance and/or resistance to first-line treatment. No leukemic transformation was identified.