Stem Cells, Vol 11, 252-262, Copyright © 1993 by AlphaMed Press
An appraisal of strategies to reduce the incidence of breast cancer
VG Jordan and M Morrow
Department of Human Oncology, University of Wisconsin Comprehensive Cancer Center, Madison 53792.
The current focus of breast cancer research is to develop a novel strategy
to prevent the disease. In this review a potential model of breast cancer
development is proposed based upon the results of laboratory models of the
induction of mammary carcinogenesis. It is clear that susceptibility to
initiation occurs in young female animals, and a preventive strategy is
more effective the sooner it is started after initiation occurs. In humans
we do not know the timing or the nature of the carcinogenic insult, but
epidemiologic studies suggest that the process is long and initiation is
most likely to occur in young adults. Hormones are the key to promotion of
the carcinogenic process and it would appear that strategically the earlier
an intervention is applied after initiation the better will be the general
effect on the population. Hormonal contraception could prevent breast
cancer if the appropriate formulation was chosen and used by all young
women. This inhibitory strategy might protect women without the need to
preselect based on risk factors. Breast cancer prevention would be a side
effect of the contraceptive method. Alternatively, tamoxifen, an
antiestrogen, is known to prevent mammary carcinogenesis in animals and
prevent the appearance of second primary breast cancers in women. This well
tested therapeutic agent is currently being evaluated in clinical trials of
selected high-risk women aged 35 and above. Finally, retinoids have shown
promise as agents in the laboratory to prevent cell replication and inhibit
mammary tumorigenesis. A trial of retinoids to prevent second primary
tumors in node negative breast cancer patients is currently underway in
Italy. The review discusses the relative merits and concerns about these
prevention strategies and proposes additional studies to be undertaken.
