Phosphorous-32 (P-32) is a radioactive isotope of phosphorus that is rarely used to treat MPNs to control blood counts. It is delivered intravenously (IV). As a radiopharmaceutical, P-32 accumulates in cells that are dividing and can be used to deliver radiation to cancerous tissues in the bone marrow, killing these cells by interfering with the cellular DNA.

P-32 can be used at varying doses and can be a highly effective treatment for MPNs, inducing long-term remissions in some patients. However, because it can damage DNA, P-32 treatment is thought to increase the risk of leukemic transformation and for this reason is usually reserved for treating older patients only under special circumstances.

P-32 is most often used in patients with polycythemia vera (PV) who are unresponsive or intolerant of other therapies (e.g., hydroxyurea, interferon, ruxolitinib) and/or phlebotomy.

Side Effects

Common side effects:

  • Decreased blood counts
  • Diarrhea
  • Fever
  • Nausea or vomiting

Additional Information:

Richard T. Silver MD Myeloproliferative Neoplasms Center 525 East 70th St., Starr Pavillion, 3rd Floor New York, NY 10021