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SE Salmon
Department of Internal Medicine, University of Arizona College of Medicine,
Tucson 85724.
Patients with IgG multiple myeloma underwent serial studies of tumor cell
kinetics including (1) estimation of the total body myeloma cell number
(TBMC), (2) measurement of the myeloma cell tritiated thymidine labeling
index (LI), and (3) calculation of the total number of myeloma cells
undergoing DNA synthesis. Intermittent courses of chemotherapy with
cycle-non-specific agents such as melphalan resulted in a marked increase
in the LI of myeloma cells in patients who had a 75% reduction in TBMC. The
long "plateau" phase of partial remission of myeloma in these patients was
associated with a continued high LI: this suggests that the plateau
resulted from a balance between the cytoreductive effects of chemotherapy
and expansion of the growth fraction (GF) of the tumor. Preliminary
attempts to capitalize therapeutically on this expansion of the GF in
several patients included administration of the cycle-active agents
vincristine and cytosine arabinoside. Vincristine appeared to induce a
further reduction in tumor in several patients, although cytosine
arabinoside appeared to be ineffective despite clear evidence of its
inhibition of DNA synthesis in myeloma cells in vivo. Further clinical
studies of the effects of cycle-active drugs on myeloma appear to be
warranted; however, successful exploitation of the dynamic change in
myeloma cell kinetics with chemotherapy will require the use of
cycle-active agents with marked selective toxicity for myeloma cells.
This article has been cited by other articles:
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| Copyright © 1975 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
