2012 EDUCATIONAL BOOK - American Society of Clinical Oncology

Previous studies have shown that women tend to overestimate
their risk of developing breast cancer and women
with a higher perceived risk of breast cancer are more likely
to be accepting of chemoprevention. 16,27 Many women, however,
have the perception that chemoprevention will not
substantially lower their risk of developing breast cancer
even after receiving information about the 50% risk reduction
associated with tamoxifen treatment. 28,29 Acceptance
of chemoprevention treatment has been shown to be significantly
higher among women with a history of atypical
hyperplasia or LCIS compared with patients at risk on the
basis of other factors (56% vs. 28%, p ��0.0001). 19
Additional barriers that contribute to the reluctance of
women to use chemoprevention are related to physician
difficulty in accurately selecting individuals most likely to
develop breast cancer and the lack of a biomarker that can
be used to monitor the effect of the drug on risk. Unlike the
monitoring of cardiovascular risk factors (e.g., cholesterol
and blood pressure), which provide a measurable target for
assessing the efficacy of cholesterol or hypertension lowering
agents, there is no available reliable biomarker to measure
the preventive effect of chemoprevention that may serve to
motivate patients to accept treatment. 15 Salant et al interviewed
women seen at a high-risk clinic, of which the
majority were black, and found that the women understood
risk not as a numerical probability or chronic disease state
but as an immediate physical sign or symptom warranting
medical intervention. Therefore, despite meeting criteria for
being high-risk using the Gail model, many women did not
“feel” at high risk and therefore were not interested in
taking breast cancer chemoprevention treatment. 30 This
finding has implications for the support of research efforts
aimed at identifying biomarkers and clinical features that
identify high-risk states and individualize the risk prediction
of invasive breast cancer as a means of improving the
uptake of chemoprevention treatment. 31
Among low-income women, acceptance of chemoprevention
is dependent also on how much it costs and whether the
cost is covered by health insurance. 28,30 At least three
studies have found that education and lower income are
inversely associated with breast cancer chemoprevention.
27,32,33 These studies did not report on the accuracy of
the women’s understanding of the risks and benefits of the
chemoprevention treatments, which is an important consideration
since a greater understanding of the risk–benefit
profile of chemoprevention has been demonstrated to result
in decreased patient acceptance of chemoprevention treatment.
24 To overcome the significant patient-related barriers
to the uptake of chemoprevention, a comprehensive strategy
is needed that educates women about breast cancer and
their competing health risks and incorporates easily accessible
decision aids that accurately convey the risks and
benefits of chemoprevention treatment.
Strategies to Improve the Uptake of Breast Cancer
Chemoprevention
Several investigators have explored the use of educational
or decision-making aids to increase the uptake of breast
cancer chemoprevention. 34,35 The goal of the decision aids is
to facilitate a discussion between the patient and provider
about breast cancer chemoprevention and help guide informed
decisions. 36 Key components of the decision aids
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have included education about breast cancer, an assessment
of the patient’s risk of breast cancer using the Gail or Claus
risk assessment models, integration of the patient’s risk of
breast cancer within the context of population risk, and an
assessment of the change in risks and benefits that would be
expected with tamoxifen or raloxifene treatment. 34-36 In two
studies that have evaluated patient willingness to take
chemoprevention after receiving a decision aid, the uptake
rates have been disappointingly low (range, 4% to 6%). 34,35
In a randomized trial designed to test whether a decision aid
intervention increased a woman’s interest in chemoprevention,
among the 6% of high-risk women who received the
decision aid and said that they were likely to take the drug,
less than 1% had initiated therapy after the intervention. 35
The challenges for PCPs considering prescribing breast
cancer chemoprevention are identifying women eligible for
treatment based on an acceptable risk–benefit profile and
communicating the net benefit estimate using a balanced
approach that allows the patient to consider her personal
preferences. Increased PCP awareness of the online Gail
risk model and access to the risk–benefit tools for tamoxifen
that were published in 1999 and updated in 2011 to include
raloxifene are needed to facilitate this process. It has been
advocated that the risk–benefit models for breast cancer
chemoprevention should be more interactive and available
online, accessible to both physicians and patients. 37 In
addition, the risk–benefit models should incorporate additional
variables, such as 5-year and lifetime mortality,
comorbidities including menopausal symptoms, and competing
health risks that are essential to an informed decisionmaking
discussion about whether to use chemoprevention
treatment. 37,38 To increase awareness and education about
cancer preventive and control strategies, the ASCO Cancer
Prevention Committee is in the process of developing curricular
material to disseminate to the educational programs
of a spectrum of disciplines, including family practice and
internal medicine. A recent breast cancer consensus statement
recommended that to advance efforts for breast cancer
prevention, the term “chemoprevention” should be replaced
with the term “preventive therapy” to remove its inappropriate
association with chemotherapy. 39
A major hurdle in promoting breast cancer chemoprevention
to the general population is the recognition that many
women who receive chemoprevention treatment will never
have developed breast cancer anyway. Because of the poor
discriminatory accuracy of the Gail risk model in determining
individual level risk of breast cancer, many women and
their physicians remain uncertain about the benefits of
treatment and concerned about the potential serious toxicities
and side effects that may affect quality of life. In
addition, advocacy groups including the Breast Cancer National
Coalition are skeptical of chemoprevention and express
concern about the lack of data on the long term
side-effects of the chemoprevention drugs. 40 Strategies to
refine risk and predict responsiveness to chemoprevention
treatment are being explored and include random periareolar
fine-needle aspiration to evaluate for cellular atypia in
otherwise normal breast tissue, breast density as a surrogate
marker for monitoring response to treatment, and
single nucleotide polymorphisms associated with increased
susceptibility. 36,39