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DECISION MAKING IN THE CONTEXT OF BREAST CANCER CHEMOPREVENTION
Decision Making in the Context of Breast Cancer
Chemoprevention: Patient Perceptions and the Meaning of Risk
Christine Holmberg, PhD, MPH
OVERVIEW
Chemoprevention with selective estrogen receptor modulators (SERMs) is considered one of the most promising risk reduction options to date
in the United States. Tamoxifen and raloxifene are both approved by the U.S. Food and Drug Administration (FDA) for breast cancer risk
reduction. However, despite endorsement from the American Society for Clinical Oncology and the National Comprehensive Cancer Network,
uptake remains low. Decision aids have been successful in improving women’s understanding and knowledge about the risk–benefit trade-offs
in decision making regarding SERMs. However, increased knowledge does not lead to increased uptake of chemoprevention for the purpose
of reducing breast cancer risk; instead, women become more reluctant to take medication that is itself associated with risks. Reasons for this
include a lack of awareness that SERMs are effective in reducing breast cancer risk, an unwillingness to increase the risk of other disease,
reluctance to take a daily medication, and the perception of tamoxifen as a “cancer drug.” In studies on hypothetical decision making in the
context of chemoprevention women indicate greater willingness to take a SERM when they are determined to be at risk. These findings suggest
a differential understanding of what risk means among the general public, health professionals, and researchers. Feeling at risk is related to
bodily signs and symptoms and not to population-derived probabilities. Such differential understanding may in part explain women’s perception
of the low efficacy of SERMs and their decision making regarding SERM use.
Breast cancer is the leading cancer in females and is responsible
for the greatest number of cancer deaths among
women worldwide, 1 including the United States. 2 According to
data for 2008 to 2010 collected in the Surveillance, Epidemiology,
and End Results (SEER) program, 12.3% of women in the
United States will be diagnosed with breast cancer during their
lifetime. There is conflicting evidence as to whether changing
behavioral factors such as a sedentary lifestyle, smoking, or regular
alcohol consumption can reduce the risk of breast cancer. 3-6
Risk reduction efforts for breast cancer therefore pose a challenge,
especially as the most effective options (young age at fırst
live birth and having multiple children) conflict with other public
health messages and efforts. 7 In this context, chemoprevention
with selective estrogen receptor modulators (SERMs) is
considered one of the most promising risk reduction options to
date in the United States. At the present time two SERMs—tamoxifen
and raloxifene—are approved by the U.S. FDA for
breast cancer risk reduction, although other medications are under
investigation. 8 Leading oncologic organizations such as the
American Society for Clinical Oncology and the National Comprehensive
Cancer Network recommend the use of these medications
for prevention of breast cancer. Uptake, however, has
lagged behind expectations. 9
Tamoxifen was the fırst medication to be approved for breast
cancer risk reduction. The Breast Cancer Prevention Trial
(BCPT) conducted between 1992 and 1998 in the United States
showed that among women with an increased risk of developing
breast cancer, those who had taken tamoxifen saw a risk reduction
of 50% compared to those in the control group. 10 The risk
reduction among women with a diagnosed atypia such as lobular
carcinoma in situ (LCIS) or atypical hyperplasia (AH) was
even greater: 56% and 86% respectively. Since these fındings, a
range of other drugs to reduce breast cancer risk have been under
investigation. 8 Thus far, only raloxifene has been approved,
after the Study of Tamoxifen and Raloxifene (STAR) conducted
in the early 2000s in the United States established the effıcacy of
raloxifene in reducing breast cancer risk. 11 Risk reduction
among women with LCIS or AH was lower in the STAR than in
the BCPT, although these women still showed a higher level of
risk reduction than women whose increased risk assessment
was based on the Gail score alone. As follow-up of both of these
studies continues, the risks and benefıts associated with both
drugs and their effects on breast cancer risk reduction are expected
to change over time. 12
PREVALENCE OF SERM USE FOR BREAST CANCER
RISK REDUCTION
In a series of studies conducted using data from the National
Health Interview Study, Waters et al 13,14 estimated the prev-
From the Charité Universitätsmedizin Berlin, Berlin, Germany.
Disclosures of potential conflicts of interest are found at the end of this article.
Corresponding author: Christine Holmberg, PhD, MPH, Charité Universitätsmedizin Berlin, Seestr. 73, D-13347 Berlin, Germany; email: christine.holmberg@charite.de.
© 2015 by American Society of Clinical Oncology.
asco.org/edbook | 2015 ASCO EDUCATIONAL BOOK
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