A basis for updating our approach to resistant acute leukemia

No studies exist documenting that chemotherapy alone eradicates tumors composed of leukemic cells in a large group of patients with tumors at any one site. Yet, its use has continued over 40 years in the absence of data. Consensus protocols exist only for testis and meningeal tumors, relying on local therapy. To constitute a body of knowledge about tumors at one site, the breast was chosen and all published cases were analyzed, with follow-up obtained, to document the behavior of acute leukemia tumors and survival after presentation. Among 235 cases (52% published since 2000), overall survival was poor, particularly for the 43% with concurrent morphologic marrow relapse, with 66-73% one-year mortality. Only 4 of 106 patients treated with chemotherapy alone survived 4 years. The majority of AML and ALL tumors were only transiently responsive to anti-leukemia treatments, including transplant, and next relapses were as, or more, common in further tumors than in marrow. A pattern of tumors similar to the metastases of invasive lobular breast cancer was revealed. When relapse occurred in marrow, durable remission was only rarely obtained. These data suggest a potential benefit of incorporating extent of disease workup at diagnosis and relapse into prospective trials. This could yield an accurate incidence of extramedullary tumors and a means to identify occult residual disease which could lead to marrow relapse. This approach could potentially result in greater success in curing acute leukemias.