Good afternoon, Senator Specter and members of the subcommittee. I am Richard Klausner,
Director of the National Cancer Institute (NCI), I am pleased to testify before you today on a
remarkable advance in cancer prevention.
The goal of preventing cancer has long been a hope and a central focus of the National Cancer
Program. Prevention can take many forms, from smoking cessation and other behavioral
changes to vaccines or antimicrobial agents against cancer-causing infections to a new field in
which medicines specifically interfere with the biologic processes of cancer development. For
the past several years, the National Surgical Adjuvant Breast and Bowel Project (NSABP), an
NCI-funded national clinical trials organization, has been carrying out a historic trial -- called the
Breast Cancer Prevention Trial, or BCPT -- to determine whether women at increased risk of
developing breast cancer can prevent the development of that cancer by taking a well-known
medicine, tamoxifen. More than 13,000 women who participated in this study have been our
partners in this work.
As with all of our clinical trials, an independent Endpoint Review, Safety Monitoring, and
Advisory Committee regularly examines the data generated by the study to monitor whether
either unacceptable or unexpected toxicities have arisen or whether the trial has succeeded in
answering the questions it has been designed to answer. This committee met most recently on
March 24. The committee concluded that the question of whether tamoxifen significantly
reduce the incidence of breast cancer in women at increased risk had been answered, and the
answer is an unequivocal yes. Nevertheless, there were, as you have heard, adverse effects of
tamoxifen which may make the very personal decision about taking tamoxifen complex. For all
of these reasons, the committee recommended that the participants of the study be notified of
these important results. It has been our commitment to the participants from the very start to
notify them as soon as clear results had been achieved,
On March 26, the NSABP leadership presented these recommendations and the data behind
them to the NCI and we -- NCI and NSABP -- agreed to accept the recommendations of the
independent advisory committee. This afternoon, NCI and NSABP will share this information
with you, describing the study, its results, and its implications, and very importantly, place this
study in the context of the larger march of science and research towards the control of this dread
disease.
The results are remarkable. They tell us that breast cancer can be prevented. A forty-five
percent disease represents one of the more dramatic finding we have seen. They represent the
power of the Nation's investment in research and conducted clinical trials. The insight that
tamoxifen might prevent breast cancer came from another NSABP clinical trial for the treatment
of breast cancer. That this drug does prevent breast cancer fits with our deep understanding of
the role of estrogen and in breast cancer and an enormous amount of science about this drug,
which has been under study for over 25 years.
While it is tempting to generalize, our conclusions must adhere to the data available. For
women whose predicted risks of breast cancer match those of the participants of this study, they
have the option to take tamoxifen with confidence that it can lower the risk of developing breast
cancer, This study provides the evidence for the magnitude of this reduction, as well as the extent
of a variety of risks that women who take this drug could face. Women need to discuss with
their physicians their own risks for breast cancer and the benefits and risks of taking tamoxifen.
The NCI will provide information about this study to the public and health care providers
through the Cancer Information Service (CIS) and through PDQ and the new NCT clinical trials
web site. The data from this study will continue to be analyzed and the information will be made
available through peer reviewed publications and via the different communication outlets of the
NCI.
The NCI is committed to communicating the importance of research findings to women and their
physicians in a clear and understandable manner. NCI has solicited feedback about the impact
the Breast Cancer Prevention Trial announcement has had on those who counsel women
regarding their decision to take tamoxifen for the prevention of breast cancer. The feedback
concerning the handling of the announcement and the materials provided to date has been very
positive. This feedback is being used to assist NCI and the NSABP to develop tools to help each
woman, and her health care provider, when making a decision about whether use of tamoxifen is
appropriate for her.
The preliminary findings from a survey of Cancer Center Directors, NCI's Cancer Information
Service, Principal Investigators of the NSABP, and the advocacy community indicate that it has
been possible for them to respond to most inquiries and counseling requests using information
already provided by NCI and NSABP. This information was disseminated through existing NCI
and NSABP communication mechanisms before or at the time of the public announcement of the
trial's early results. A new mechanism was also used. NCI launched on the day of the
announcement a new clinical trials web site, which included information about the benefits and
risks of tamoxifen.
For women whose risks of developing breast cancer fall within the range of this study, tamoxifen
can provide, for the first time, an option to reduce that risk, much as new cholesterol-lowering
medication can reduce the risk of heart attacks. But that option must be weighed carefully and
on an individual basis.
This emphasis on individual risk is important. Our ability to identify individuals at risk for
disease and to begin to rationally intervene, based upon our knowledge of the disease process, is
what medicine will become.
Great interest has been generated about genetic Predisposition to breast cancer, and we know that
some breast cancer is linked to certain mutations. It is likely that some of the women in this
study, especially those with very strong family histories of breast cancer, carry such a genetic
predisposition. While it is reasonable that such women would also experience a decreased risk
of breast cancer with tamoxifen, no specific gene testing has been done. As further analyses of
the data from this clinical trial are done, we hope to be able to provide more information over the
next 6-12 months as to whether women with alterations in BRCAI & 2, the two known genes
whose alterations predispose to breast cancer, were protected from cancer in this trial. I would
like to emphasize, however, that there are many important considerations as to how new
knowledge about genetics can and should be made a part of medical decision-making that further
complicate this process.
This study is not an end. It is rather a very propitious beginning. But it tells us that it is possible
to prevent breast cancer. Tamoxifen is far from ideal. Its efficacy is only partial and it has
significant risks. To move forward will require new agents and new clinical trials. Newer
selective estrogen receptor modifiers are being developed and will be tested, The NCI hopes to
be able to follow this study soon with additional clinical trials to find answers to the many
questions that remain.
Thank you, Mr. Chairman, for your continued support for career research. I would be pleased to
answer any questions the Subcommittee may have.
