Overview of radiation myelotoxicity secondary to radioimmunotherapy using 131 i‐lym‐1 as a model

Academic Article


  • The radiation dose‐limiting toxicity from radioimmu‐notherapy has been myelotoxicity in the absence of bone marrow reconstitution (transplantation). Myelotoxicity can be assessed directly by biopsy examination of the bone marrow and indirectly by peripheral blood counts. In patients with B‐cell malignancies, thrombocytopenia has been the initial and most severe manifestation of131 I‐Lym‐1 radiation toxicity from treatment. Manifestations of myelotoxicity varied greatly among the patients and from one treatment dose to another in the same patient, suggesting that additional factors were present. There was an increased likelihood of Grade 3‐4 hematopoietic toxicity after 131 I‐Lym‐1 treatment if the patient had peripheral blood cell abnormalities before undergoing 131 I‐Lym‐1 treatment. Fractionation of the total131 I‐Lym‐1 dose was associated with less toxicity. In many patients, myelotoxicity could not be explained by marrow radiation dose (0.36 ± 0.13 rads per administered mCi) from 131 I‐Lym‐1 in the blood and body alone. Bone marrow examination and 131 I‐Lym‐1 imaging usually provided evidence for additional marrow radiation from 131 I‐Lym‐1‐targeting of marrow malignancy and also for residual toxic effects from prior treatment in these patients. Immunohistologic and imaging examination of the bone marrow performed with the intended treatment antibody allowed assessment of extent of marrow malignancy and prediction of degree of myelotoxicity from subsequent treatment. Treatment programs (and protocols) for radioimmunotherapy should incorporate these methods into the decision process. Larger amounts of 131 I‐Lym‐1 can be used in patients selected to have relatively normal peripheral blood cell counts and normocellular bone marrows uninvolved by the malignancy. These observations appear to be relevant to the maximum tolerated dose in radioimmunotherapy for other malignancies as well. Cancer 1994; 73:1038‐48. Copyright © 1994 American Cancer Society
  • Authors

    Published In

  • Cancer  Journal
  • Author List

  • Denardo GL; Denardo SJ; Macey DJ; Shen S; Kroger LA
  • Start Page

  • 1038
  • End Page

  • 1048
  • Volume

  • 73
  • Issue

  • 3 S