Women do not die of primary breast cancer. Over 90% of breast cancer deaths are due to the spread of the disease to other parts of the body, such as bone, lungs, liver and brain. Approximately 162,000 women are living with metastatic breast cancer in the United States, according to one expert. However, the exact numbers are neither collected nor maintained, and we do not have information on historical trends.
Close to one-third of the women considered “cured” of breast cancer will suffer recurrences and metastatic spread of the disease, often many years after their initial diagnosis. While researchers have identified treatments that sometimes shrink or slow metastatic tumors, such as estrogen blockers, radiation and chemotherapy, they are most often temporary. Treatments to eradicate metastasis do not exist. There is no cure.
During 2011, NBCC held two strategic summits around the priority areas of primary breast cancer prevention and prevention of breast cancer metastasis. The Summit on Prevention of Metastatic Breast Cancer, held August 26-28, 2011, in Aspen, CO, represented the first step in focusing efforts on understanding how to prevent breast cancer metastasis. Though it is the spread of breast cancer that ultimately takes the lives of women who die from the disease, only a fraction of the research into breast cancer is aimed at a greater understanding of this process, and ultimately, in understanding how to intervene and prevent metastasis. NBCC gathered a diverse group of breast cancer advocates, scientists, and clinicians from across the United States, Canada and Europe to begin to outline a research plan of action for the prevention of metastasis.
Investigators currently looking at the biology of breast cancer metastasis—the genetics, the cellular mechanisms, and the role of the immune system—were brought together with investigators who have different perspectives, such as those who have created mathematical models of metastasis, or who have been applying evolutionary theory to cancer progression, along with those who work outside of the field, such as physicists.
During the meeting, participants divided into three breakout groups to discuss the breast cancer metastatic process—what we know, what we need to know, creative approaches for prevention, how different approaches can complement one another, and finally, what we need to do to move forward to achieve progress for women.
Each breakout group took a slightly different approach. Breakout Group One proposed a consortium of institutes aimed at developing a multi-faceted approach to prevention of metastasis for those at highest risk, based on the idea that multiple interventions will work better and prevent resistance.
The consortium would focus on three areas: multidisciplinary research projects to develop interventions reflecting a variety of approaches, such as targeting dormancy, the immune system, lifestyle interventions, or the tumor environment; biomarker development focused on identifying which patients are likely to benefit most; and multiple, small, “secondary prevention” clinical trials with adaptive designs to look for large effects and to collect tissue at regular intervals for information to be fed back into intervention and biomarker development.
Breakout Group Two focused on understanding what occurs between primary diagnosis and breast cancer spread or metastasis. The group identified several key research questions about the role of breast cancer cells and the host in tumor dormancy and metastasis, and important areas for clinical translation, including developing the technologies to detect the first signs of metastasis.
Breakout Group Three focused on looking for early stages of metastasis through improved imaging, exploration of biomarkers, tissue collection, and whole-genome sampling to identify host factors; a large, prospective, longitudinal cohort study, to follow women from the time of diagnosis, comparing those who develop distant metastases with those who do not; and exploring the repurposing of approved drugs, investigational drugs, and other interventions to develop less toxic treatments