Report of the 2011 ASCO Breast Cancer Symposium, San Francisco, CA,
September 8-10, 2011
The annual ASCO (American Society of Clinical Oncology) Breast Cancer Symposium brought together more than 1,000 medical professionals from around the world to San Francisco, to present and discuss the latest translational and clinical research on breast cancer. The Symposium featured many lively presentations and discussions on multidisciplinary topics including breast cancer prevention, detection and screening, breast-conserving local therapy, radiotherapy, and healthcare policy. BCRF grantees and BCRF-supported research were featured prominently throughout the Symposium.
New BCRF grantee, Seema A. Khan, MD, MPH (Northwestern University, Chicago), provided a succinct overview of which strategies are appropriate for which women who may be at risk for the development of breast cancer. For premenopausal women at high risk for the development of sporadic (non-inherited) breast cancer, tamoxifen is the preferred preventive agent. In postmenopausal women, exemestane and raloxifene are options in the absence and presence of osteoporosis, respectively; tamoxifen is favored only in women who have undergone a hysterectomy and who are at risk for osteoporosis. Dr. Khan reported that, in addition to ongoing clinical trials of low-dose tamoxifen, there are also investigations of the usefulness of metformin, an inexpensive and widely used drug for diabetes, as a preventive agent for breast cancer. She reported that for BRCA1/2 mutation carriers, both prophylactic mastectomy and removal of the ovaries are effective surgical interventions for reducing breast cancer risk. For women who are not BRCA1/2 carriers, prophylactic mastectomy may be appropriate for select patients at very high risk.
Of note to many healthy women at risk, a non-BCRF funded investigator, Christine Friedenreich, PhD, of the University of Calgary, presented data suggesting that physical activity-particularly longer-duration, lifetime activity of at least moderate intensity (6.5 hours per week)-reduces breast cancer risk by up to 25%. This is consistent with a growing body of evidence linking calorie consumption and obesity to risk.
The meeting also focused on issues faced by women who have been successfully treated for breast cancer. Cognitive impairment symptoms following breast cancer treatment affect approximately 20% to 30% of survivors, according to data presented by Janette L. Vardy, MD, PhD (University of Sydney, Australia, past Conquer Cancer Foundation/ASCO/BCRF Career Development Awardee). Although the etiology is not well understood and there are no proven interventions for ameliorating these symptoms, Dr. Vardy reported that further research is warranted on the effects of exercise, cognitive rehabilitation, and modafinil (generally prescribed for sleep disorders).
Patricia A. Ganz, MD (UCLA) gave an overview of the challenges in delivering survivorship care to the more than 2.5 million breast cancer survivors in the US alone. Opportunities for intervention may be missed because many survivors are unaware of their risk of developing cognitive and other treatment related issues, such as fatigue. The "one size fits all" approach is not ideal for survivorship care because breast cancer is not just one disease. Also, cancer treatment usually occurs in isolation from primary health care delivery, so opportunities for coordinated approaches among physicians can be lost. The key approaches in the care of survivors, according to Dr. Ganz, are palliation of symptoms, health promotion, and prevention of recurrence. Bruce Haffty, MD (University of Medicine and Dentistry of New Jersey) described his own academic medical center's comprehensive survivorship program as an example.
Bryan P. Schneider, MD (Indiana University, Conquer Cancer Foundation/ASCO/BCRF Advanced Clinical Research Awardee) reported on behalf of the cooperative groups on a trial of over 4,500 patients with early stage breast cancer treated with adjuvant chemotherapy including a taxane and followed for eight years. This study examined the relationship between a toxicity - nerve damage called "neuropathy" - and outcomes, and concluded that there is no significant difference in overall survival, disease-free survival, or recurrence-free survival between those who experienced it and those who. did not. Given the lack of association between neuropathy and outcome, Dr. Schneider reported that he and his colleagues will now work to validate several normal gene variations, called "polymorphisms" that can predict for protection against taxane-associated neuropathy.
William J. Gradishar, MD (Northwestern University) discussed Dr. Schneider's presentation and related ones focused on the challenging issue of neuropathy, which is experienced by more than 55% of patients who receive taxanes (chemotherapeutic agents which include paclitaxel (Taxol®), albumin-bound paclitaxel (Abraxane®), and docetaxel (Taxotere®). While several protective agents have been tested, none so far have proven to be effective in preventing neuropathy; therefore, Dr. Schneider's planned research exploring genetic predictors of this toxicity may be critical.
Edith A. Perez, MD (Mayo Clinic) reported on several published and ongoing studies to clarify three sometimes-uncertain issues regarding the use of HER2-targeted therapy in clinical practice: how to select appropriate patients for HER2 therapy, how to optimally apply trastuzumab in the adjuvant setting, and how to use anti-HER2 therapy in advanced (metastatic) disease. Dr. Perez provided interim data from the global clinical trial (ALTTO) which is comparing adjuvant trastuzumab, lapatinib, sequencing of these agents, and their concurrent combination (four different treatment options). The findings show that single-agent lapatinib appears to be inferior in comparison with single-agent trastuzumab with regard to disease-free survival and thus should not be used (as a single therapy) in the adjuvant setting. This trial is still ongoing, and final results will be forthcoming.
In the meeting's final session, Julie R. Gralow, MD (University of Washington) reviewed the potential roles of agents targeted to bone loss during treatment for breast cancer. Denosumab and several bisphosphonates (such as zoledronic acid and pamidronate) have been approved for reducing skeletal-related complications in patients with bone metastases, and on September 21st denosumab was approved to prevent bone loss in patients receiving aromatase inhibitors as adjuvant therapy. In addition to preserving bone mineral density, published results now suggest that adjuvant bone-targeted therapy may also inhibit breast cancer recurrence, although study findings have been mixed. Several studies are ongoing to better understand the potential use of bone-targeted agents.