Approximately 3.5 million women in the U.S. are living with breast cancer, including more than 154,000 with disease that has spread beyond the breast to other parts of the body, known as metastatic breast cancer (stage IV). The outlook for non-metastatic breast cancer patients has overall improved, with an average five-year survival rate reaching close to 100 percent for people with stage 0 or I breast cancer, and 93 percent for people with stage II breast cancer.
The prognosis for those women diagnosed with metastatic breast cancer is not as promising. But, as research continues, progress is emerging. The percentage of women surviving five years with metastatic breast cancer (aged 15-49) doubled from 18 to 36 percent between 1994 and 2012.
“Sometimes metastatic breast cancer can be considered much more of a chronic disease,” said Denise A. Yardley, M.D., a senior investigator at the Sarah Cannon Research Institute in Nashville, TN. “I’ve seen a positive impact on patients who continue relatively normal lives despite their disease and treatment.”
Treatment Advances Are Constantly Occuring
There are many forms of metastatic breast cancer. Patients’ tumors can be either positive or negative for growth receptors, signaling the presence or absence of the known drivers of the disease. And they may or may not have disease driven by HER2 (human epidermal growth factor receptor 2) receptors. That complexity and the cross signaling from the HER2 receptor to other growth factor receptors, as well as the multitude of treatments available to treat metastatic breast cancer are part of the reason it has been a particularly difficult disease to treat. But translational researchers are making significant strides to further understand tumor biology and the genomics behind breast cancer subtypes.
The end result is a more tailored treatment approach based on a patient’s specific tumor biology and other clinical factors. With an expansion in targeted therapies, there is greater value in having patients’ tumors thoroughly examined so treatments are better selected. “We’re continuing to try to improve our precision medicine and really tailor treatments to what’s going on in that specific patient’s tumor,” Yardley said.
Doctors also have a better understanding of how to use the growing array of treatments. While combination therapy is used in early stages of breast cancer, recent studies have provided additional evidence on how to sequence treatment options for their patients. We now also focus on balancing symptom control with quality of life and partnering with our patients to make appropriate treatment selections at any given time.”
There’s every reason to be optimistic for patients facing the diagnosis and challenges of metastatic breast cancer today.
Preventing Metastasis from the Start
About 30 percent of women with early stage breast cancer eventually develop metastatic disease. So in addition to improving the treatment of metastatic breast cancer, researchers are trying to continue to improve the cure rate and thus prevent breast cancer from becoming metastatic in the first place.
Most women with early stage breast cancer will have surgery during the course of their treatment. Now, many are also candidates for a variety of systemic therapies, either before or after surgery, to reduce the number of potentially microscopic cancer cells left behind and prevent the disease from coming back. Chemotherapy is usually reserved for patients at higher risk for a recurrence or metastasis.
“We want to make sure we’re appropriately recommending specific therapies but sparing patients who have a lower risk of disease recurring and becoming metastatic,” Yardley said.
By administering these medications earlier, when the disease is still operable, researchers aim to increase the cure rate and prevent—or at least delay—recurrence and metastasis in breast cancer patients.
More Work to Be Done
Admittedly, much work remains to be done, according to Yardley. Over the last 60 years, breast cancer survival rates have tripled, but metastatic survival rates have a long way to go before they reach that level.
Clinical trials play an essential role in exploring new treatments and approaches in metastatic breast cancer, and these trials continue to become more targeted as researchers learn more about the disease subtypes. For instance, while immunotherapies have not proven effective in studies for metastatic breast cancer in general, trials investigating immunotherapy in specific breast cancer subtypes such as triple negative breast cancer have shown promising activity. Thus, targeted treatments in combination with chemotherapy continue to demonstrate great promise.
“The science has become astounding, allowing us to manipulate the biology of metastatic breast cancer through very tailored approaches,” Yardley added. “There’s every reason to be optimistic for patients facing the challenges of metastatic breast cancer today.”
To learn more about a patient’s experience with metastatic breast cancer, read “How This Metastatic Breast Cancer Survivor Told Her Family About Her Diagnosis.”