Marrow chromosome studies in “preleukemia”: Further correlation with clinical course

New data are provided in a long-term investigation of the prognostic value of marrow chromosome studies in “preleukemic” states. Fifty-one patients have now been studied and followed for at least a year or until death: 26 with the myeloproliferative syndrome, including polycythemia vera; 16 with idiopathic pancytopenia; and 9 “miscellaneous” patients with unexplained anemia, neutropenia, leukocytosis, or thrombocytopenia. No chromosome changes were found in this last group, and no leukemia developed. Sixteen of the 42 patients in the myeloproliferative and pancytopenia groups had a marrow chromosome abnormality when studied, and 9 of these developed rapidly fatal clinical leukemia within 3 months thereafter. The other 7 patients (including 3 in whom the marrow chromosome change may have been induced by 32P therapy) remained free of leukemia when followed up to several years. Neither the type of chromosome change nor the size of the abnormal cell clone in the marrow was of prognostic value. Four of the 26 patients without chromosome changes in the myeloproliferative and pancytopenia groups developed leukemia, one within a few weeks and the others, 7 to 26 months after study. It is concluded that if a marrow chromosome abnormality is detected in a non-irradiated “preleukemic” patient, the risk of developing clinical leukemia within the next few months is great, and patients who show such progression probably had subclinical leukemia already present in the marrow at the time of study. If, however, frank leukemia does not appear within 3 months, “preleukemic” patients with marrow chromosome abnormalities are perhaps thereafter at no greater risk than comparable patients without such changes.