SABCS: Focus on Prevention and Risk Assessment

The annual San Antonio Breast Cancer Symposium (SABCS) is being held December 6–10 in San Antonio, Texas. The symposium brings together basic science researchers and clinicians for the latest breast cancer research–related progress. The symposium has evolved from a 1-day local conference to a 5-day international meeting focusing on clinical, preventive, diagnostic, translational, and basic research.

Part of the focus this year is on new preventive measures.

One of the highlights of this year’s meeting is the presentation, “Breast Cancer and the Environment: A Life Course Approach,” a report issued by the Institute of Medicine (IOM). While breast cancer susceptibility gene testing is routine, and women have no control over this risk type, environmental risks are something that women may be able to influence. The IOM will report highlights of their assessment of the risk of breast cancer posed by different environmental factors, which may be targeted for future research.

One such environmental factor is diet, the focus of a randomized study from the Genesis Prevention Center at University Hospital in South Manchester, England, that compares energy-restricted diets, as a potential strategy for breast cancer prevention, to standard diets. Lower carbohydrate consumption and energy restrictions in general have implications for insulin metabolism and oxidative stress generation, which may affect breast cancer onset.

Also highlighted are new data on risk factors for first onset and recurrence of breast cancer.

Obesity is generally associated with worse breast cancer prognosis, but the effects of body fat on type of adjuvant therapy administered have not been looked into in detail. A study conducted at the Baylor College of Medicine, Houston, Texas will be presented that examines the association of obesity with treatment type and outcome.

Another study will show how a prior history of diabetes and obesity are related to incidence of breast cancer using health care data from over one million people in Sweden. The study also examines any effects from diabetes medications on cancer risk.

To look at the risk of recurrence in survivors, researchers assessed dietary intake on breast cancer recurrence rates as a subanalysis of over 2000 women who were part of the Women’s Healthy Eating and Living (WHEL) Study that tracks breast cancer survivors for an average of seven years. The study involves looking at how various carbohydrate intake levels may influence breast cancer recurrence. The results may have important implications for survivors as dietary factors such as carbohydrates may stimulate activation of insulin-like-growth-factor receptors (IGF-IR) that are often expressed in breast tumors.

Three studies will present data on potentially new subclassifications of breast cancers, allowing for tailoring of treatment and more accurate recurrence and new onset risk assessment.

To facilitate more personalized treatment of hormone receptor-positive invasive breast cancer and help predict whether these patients may experience early, late, or no recurrence, researchers at the Georgetown Lombardi Comprehensive Cancer Center have addressed the biological differences of ER-positive disease that relapses either early or late, in women initially treated with tamoxifen. ER-positive breast cancers may recur more than 10 years after the initial diagnosis and successful adjuvant endocrine therapy but the reason for this is not understood. The study to be presented at SABCS may allow ER-positive tumors to be further classified into distinct subtypes that are associated with early or late recurrence.

The second study assessed women with a germline mutation in BRCA1 or BRCA2 for risk of developing new primary tumors of the breast. Although the risk of developing a synchronous or metachronous bilateral breast cancer is known, the current study attempts to narrow down a more precise risk estimate of these events as well as additional risk factors at play.

Lastly, a study assesses a new test that may parse ductal carcinoma in situ (DCIS) patients into high-risk patients that should receive radiation as a preventive measure and those for whom radiation therapy is unnecessary.

Currently, doctors advise DCIS patients on their risk of recurrence and the potential need for radiation on top of surgery, which is associated with reduced local recurrence but more adverse events. This new study assesses the ability of a multigene test to predict a high-risk patient that will likely relapse, and therefore should receive radiation treatment on top of surgery. This is the first time a multigene test has been used to differentiate low-risk and more aggressive forms of DCIS, potentially allowing patients to be spared of unnecessary radiation treatment while at the same time, treating higher-risk patients earlier to prevent recurrence.

Preventive and Risk Study Highlights:

Preventive studies

• Breast Cancer and the Environment: A Life Course Approach. Report Release from an IOM Committee. Wednesday, December 7, 2011; 1:45 p.m.

• Intermittent Dietary Carbohydrate Restriction Enables Weight Loss and Reduces Breast Cancer Risk Biomarkers. Abstract P3-09-02. Presented by Michelle Harvie, PhD, SRD

Risk studies

• Obesity, Adjuvant Therapy, and Survival Outcomes in Early-Stage Breast Cancer. Abstract P1-08-0. Presented by Sao Jiralerspong, MD, PhD

• Breast Cancer among Patients with Diabetes, Obesity and Abnormal Blood Lipids-A Population-Based Register Study in Sweden. Abstract P1-08-06. Presented by Hkan Olsson, M.D.

• Change in Carbohydrate Intake and Breast Cancer Prognosis. Abstract P3-09-01. Presented by Jennifer A. Emond, MS

• Molecular Signaling Distinguishes Early ER Positive Breast Cancer Recurrences Despite. Abstract S1-8. Presented by Minetta C. Liu, MD. Thursday December 8, 2011, 11:15 a.m.

• The Risk of Contralateral Breast Cancer in BRCA1/2 Carriers Compared to Non-BRCA1/2 Carriers in an Unselected Cohort. Abstracct S4-2. Presented by Alexandra J. van den Broek, MSc. on Thursday, December 8, 2011; 3:30 p.m.

• A Quantitative Multigene RT-PCR Assay for Predicting Recurrence Risk after Surgical Excision Alone without Irradiation for Ductal Carcinoma In Situ (DCIS): A Prospective. Abstract S4-6. Presented by Lawrence J. Solin, MD, FACR, FASTRO will be presented at on Thursday December, 8, 2011; 4:30 p.m.