What is the optimal approach for breast cancer risk assessment?

OVERVIEW: As more options become available for women at high breast cancer risk, the quantitative determination of risk has become increasingly important. Breast cancer risk assessment is important in making medical decisions about time of screening and surveillance, postmenopausal hormone-replacement therapy, genetic counseling and testing, ductal lavage, chemoprevention and prophylactic mastectomy. In addition to the increasing number of medical decisions affected by a patient’s breast cancer risk, there are an now a number of methods available to assess a patient’s risk. The Risk Assessment Working Group* — comprised of research leaders from a variety of disciplines — was formed to address these issues and create a management strategy to assist clinicians in sorting through these issues. As an initial project, in December, 2001, nearly 600 surgeons who had previously attended the Miami Breast Cancer Conference responded to a survey examining how women at high risk for developing breast cancer are identified and managed. The results are considered a baseline to look at education strategies to optimize the use of quantitative risk assessment.

* Risk Assessment Working Group: Terry Bevers, Laura Esserman, Linda Frame, Darius Francescatti, Anne-Renee Hartman, Alan Hollingsworth, Suzanne Klimberg, Monica Morrow, Wendy Mikkelson, David Nathanson, Lisa Newman, Joyce O’Shaughnessy, Freya Schnabel, Eva Singletary, and Victor Vogel, Chair.

When assessing a patient (personal and family history), which breast cancer risk factors do you routinely include?

	Family history	99.3%
	Previous biopsies (even benign)	95.2%
	Reproductive history (age at menarche, 1st childbirth)	89.7%
	Use of hormone replacement therapy	87.1%
	Lifestyle factors (diet, alcohol, smoking, etc.)	60.1%
	Race	53.0%

What method(s) do you use to assess a patient’s risk for breast cancer?

	Patient profile (personal & family history)	93.1%
	Quantitative risk assessment	79.8%
	Formal genetic counseling and/or testing	36.6%
	Ductal lavage	7.3%

Are you familiar with these quantitative risk assessment tools?

In your practice, what factors determine a patient’s need for the following breast cancer risk assessment tools?

Which of the following management options do you use for your high-risk patients (determined by history and/or quantitative risk assessment)?

	More frequent screening (physical exam & mammography)	81.4%
	Closer surveillance (ultrasound, MRI, ductography)	51.0%
	Referral to a genetic counselor	40.5%
	Perform ductal lavage	10.2%
	Referral to an oncologist or other specialist	32.6%
	Referral to STAR trial	48.3%
	Discuss/prescribe tamoxifen	75.9%
	Discuss/prescribe raloxifene	18.9%

What are the biggest impediment(s) to performing risk assessment and risk reduction?

	Woman’s reluctance to take tamoxifen	51.8%
	Lack of patient interest and compliance	32.3%
	Lack of acceptable reimbursement for risk assessment and counseling	28.1%
	Lack of training in risk assessment and counseling	27.9%
	Lack of adequate benefit to patient	13.8%

RATIONALE FOR RISK ASSESSMENT

In the past there was very little reason for clinicians to spend a lot of time understanding breast cancer risk, but in recent years things have changed. First, the clinical availability of tamoxifen on the market as a drug which has shown to reduce breast cancer incidence in high-risk women mandates a better understanding of who should consider taking that drug and who should not.

In addition, the public is more aware of the idea of breast cancer risk, and women frequently seek counseling from their physicians about their level of risk. Although prophylactic mastectomy has been around as a breast cancer risk reduction strategy for a long time, in an era of breast conserving therapy for most established invasive cancer, its role may be changing. It may be limited to the very highest risk women, such as those with genetic mutations that carry a very high level of risk. All this mandates that clinicians understand and be conversant with the concept of risk.

—Monica Morrow, MD

ROLE OF THE GAIL MODEL IN RISK ASSESSMENT

The main risk assessment tool currently available is the Gail Model. Based on a woman’s history, it provides us a mathematical estimate of that woman’s breast cancer risk. This is vital information for the patient and physician. Obviously, the higher her risk, the more motivated both will be to initiate risk reduction strategies, such as chemoprevention. Conversely, if the patient has an average to low risk, she can be reassured, and that’s an important role for the physician as well. We now have some assessment tools to separate low- to average-risk women from those who may need aggressive interventions and treatments.

—Joyce O’Shaughnessy, MD

WOMEN’S OVERESTIMATION OF THEIR BREAST CANCER RISK

I’ve been studying women with increased risk for over a decade. What we know from our studies and studies of others is that women overestimate their risk. They have a heightened anxiety about their risk. Anytime we can give them a more realistic, objective understanding of their risk, we help them — even if they’re high-risk because the greatest anxiety comes from not knowing. So we perform risk assessments in order to calculate a patient’s breast cancer risk over a 5- or 10-year period and present this information to the patient. Risk assessment accomplishes two objectives. First of all, most patients are low- or average-risk and it provides us the opportunity to educate them about routine screening and reassure them. Secondly, we can identify the high-risk women and offer them risk reduction strategies, such as tamoxifen.

—Victor Vogel, MD

QUANTITATIVE RISK ASSESSMENT

The recent success of the National Surgical Adjuvant Breast and Bowel Project (NSABP) tamoxifen chemoprevention trial and the increasing availability of novel agents targeting the early stages of carcinogenesis have resulted in a renewed interest in chemoprevention, in general, and in the need to more accurately assess cancer risk to identify appropriate candidates for participation in cancer prevention trials and to monitor early preclinical events. In the case of breast cancer, the epidemiologic literature is replete with studies describing various demographic, reproductive, and medical factors associated with risk. These risk factors have been quantified in a mathematical model developed by Gail et al, which predicts the risk for breast cancer on the basis of age, race, age at menarche, parity, family history of breast cancer, and history of breast biopsies.

This model served as the basis for determining eligibility for the NSABP tamoxifen chemoprevention trial and is now being used clinically to identify women who would benefit from tamoxifen for risk reduction. Although extremely useful in clinical decision-making, the Gail model does little to elucidate the molecular events that culminate in cancer, and it is not useful in the evaluation of novel agents for their chemopreventive properties, for which we need biologic end points.

—Daly MB, Ross EA. J Natl Cancer Inst 2000;
92(15):1196-7.

INTERVENTION TO REDUCE BREAST CANCER RISK

Individual breast cancer risk measurement has recently become more than an intellectual exercise, as there are now several interventions documented to lower breast cancer incidence in increased-risk women. In April 1998 investigators with the National Surgical Adjuvant Breast and Bowel Project (NSABP) reported that tamoxifen can reduce the incidence of breast cancer by nearly 50%. Prophylactic mastectomy was recently shown to lower breast cancer incidence by more than 90% in women with a strong family history of the disease, and most recently, prophylactic oophorectomy was associated with a 47% reduction in breast cancer incidence among women with BRCA1 gene mutations. Each of these interventions has its own risk:benefit ratio, so now more than ever, there is a need to accurately measure personal breast cancer risk.

—Euhus DM. Breast J 2001;7(4):224-32.
Abstract

RISK MANAGEMENT STRATEGY

Breast health history and quantitative risk assessment are used to stratify patients into Very High, Elevated/High or Average risk categories. The figure below provides a management strategy for women in each of these risk categories. Click here to View Graphic

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