Each December, medical experts and researchers from around the world meet at the 5-day San Antonio Breast Cancer Symposium to share the latest findings from breast cancer clinical trials.
Read on for updates in triple-negative, HER2-positive, hormone-positive, early-stage and metastatic breast cancer coming from the 2013 symposium, held December 10–14. We also encourage you to listen to our recent webinar, reporting on the findings.
Pre-surgery Treatments Valuable for Triple-Negative Breast Cancer
Findings from two phase II trials show improvement in the ability to eliminate breast cancer at the time of surgery, following treatment with pre-surgery chemotherapy.
No sign of cancer at the time of surgery is called pathologic complete response (pCR). Researchers believe pCR may predict better long-term overall survival outcomes, by reducing the risk of the cancer coming back.
The first trial, I-SPY2, is still recruiting. Investigators are exploring whether treating women before surgery with chemotherapy combined with new medicines thought to target the biology of individual tumors is better than treatment with pre-surgery chemotherapy alone. Chemotherapy given prior to surgery is called neoadjuvant chemotherapy.
I-SPY2 uses an adaptive study design, which means the researchers are able to change the study as they learn more about the treatments being tested. They decide which new medicine each person receives based on the tumor characteristics, allowing for more individualized treatment.
Researchers announced at San Antonio that women with triple-negative breast cancer who were treated with the first new medicine assessed, veliparib, a PARP inhibitor, combined with carboplatin (Paraplatin), were more likely to show no signs of cancer at surgery than women treated with standard chemotherapy alone.
Fifty-six percent of women treated with the veliparib combination were estimated to achieve a pCR, compared with 26 percent of those treated with standard therapy.
The second trial, CALGB/Alliance 40603, found that adding carboplatin or bevacizumab (Avastin), or both, to standard neoadjuvant chemotherapy also increased the number of women who had a pCR, compared with women treated with standard neoadjuvant chemotherapy alone. In this trial:
- 60 percent of women treated with bevacizumab plus carboplatin had a pCR
- 49 percent treated with carboplatin alone had a pCR
- 43 percent treated with bevacizumab had a pCR, and
- 39 percent treated with standard therapy had a pCR
For this study, the researchers defined pCR as having no cancer in the breast and the lymph nodes.
Researchers found that treatment with carboplatin was more effective than bevacizumab at clearing both the breast and lymph nodes of cancer. In the U.S., bevacizumab is not available for use outside of the clinical trial setting.
It is important to note that both trials involved small numbers of participants. Their findings suggest larger, phase III trials are necessary to continue assessing the impact of these treatments.
Read more about I-SPY2.
Read more about CALGB/Alliance 40603.
Taxane Chemotherapy Useful for Stage I, HER2-positive Disease
Results from the APT trial suggest women with early-stage, HER2-positive breast cancer, who have very small tumors, may not need to pair trastuzumab (Herceptin) treatment with an anthracycline-based chemotherapy.
Because HER2-positive breast cancer is generally more likely than other breast cancers to come back, doctors recommend treatment with both trastuzumab and chemotherapy. In past studies, researchers used anthracycline chemotherapy, such as doxorubicin (Adriamycin) or epirubicin (Ellence). This anthracycline-trastuzumab combination lowers the risk of recurrence by as much as 50 percent.
But anthracyclines increase the risk for congestive heart failure, or weakening of the heart muscle, and leukemia. Researchers wanted to find out whether it is possible to use a non-anthracycline-based chemotherapy with trastuzumab to treat smaller, lymph node-negative, HER2-positive breast cancer. APT explored whether using paclitaxel (Taxol) and trastuzumab was as effective at preventing recurrence as today’s standard of care in treating 406 women with HER2-positive cancer.
All participants had cancer that did not travel to the lymph nodes and measured less than 3 cm. Women received paclitaxel plus trastuzumab for 12 weeks, then took trastuzumab alone for 9 additional months.
At 3.6 years of follow-up, about 2.5 percent of the women had a recurrence or died, and 2 women had a distant recurrence or metastasis.
At 3 years, 98.7 percent of the women were alive, without the cancer returning.
These findings suggest that women with small HER2-positive breast cancers can be treated with a taxane chemotherapy and have the same benefits as they would have with an anthracycline medicine.
APT was a phase II trial, and its participants were less likely to have a recurrence because of the early stage of the cancer, so further research will need to confirm these findings.
Read more about APT.
Exercise Lessens Joint Pain Caused by Aromatase Inhibitors
The HOPE study found that postmenopausal women with early-stage, hormone receptor-positive breast cancer who exercised experienced less joint pain from aromatase inhibitors (AIs) than their peers who did not.
Aromatase inhibitors are medicines that block the natural hormones in the body from helping breast cancer to grow or spread. They are given as a standard treatment to women with hormone receptor-positive disease who are postmenopausal, or who no longer have a monthly period for longer than 1 year. Though they are effective at preventing the cancer from coming back, AIs are known to cause joint pain.
The 121 trial participants were broken into two groups. One group went to resistance and strength training classes twice a week with a personal trainer. They performed moderate aerobic exercise, like brisk walking or light jogging, for 150 minutes per week throughout 1 year.
Members of the other group were called once a month to check that each was taking her AIs as prescribed. These women were not directed to exercise, though they received information on its benefits. All participants reported at least mild joint pain before they enrolled in the study.
After 1 year, the researchers found that the women in the exercise group reported a 20 percent decrease in pain, pain severity, and pain interference (the impact of pain on their day-to-day lives) than they experienced before they started the program. Their peers in the second group reported no change in pain, or small increases in pain.
Read more about Hope.
Bone-Strengthening Medicines Improve Survival, Prevent Bone Recurrence in Postmenopausal Women
Bone-building medicines called bisphosphonates are sometimes given to postmenopausal women who are taking aromatase inhibitors for breast cancer.
These medicines help stop bone weakening, which can be a side effect of cancer treatment. They also are commonly given to women with cancer that spread to the bone and who have a greater risk of fractures and breaks.
Researchers have explored whether bisphosphonates like zoledronic acid (Zometa) and clodronate have an impact on breast cancer survival and recurrence, the chance of the cancer coming back. Many past trials reported conflicting results.
To better understand the role of bisphosphonates in breast cancer, the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) collected data from 36 past studies and analyzed it in what is called a meta-analysis. Together, the studies had more than 22,000 participants who were diagnosed with early-stage disease.
Though the data showed no significant impact of bisphosphonates on survival or recurrence rates among premenopausal women, when they assessed data on the 11,306 postmenopausal women, the risk of breast cancer spreading to the bone was reduced by 34 percent. Their risk of breast cancer-related death dropped by 17 percent.
Compared with postmenopausal women who were not given bisphosphonates, the women who took them were 3.5 percent less likely to have a distant recurrence, or breast cancer that spreads to other organs of the body. They were also 2.9 percent less like to have the cancer spread to bone.
Overall, the researchers believe these findings suggest that bisphosphonates may improve survival and lower the risk of cancer coming back in postmenopausal women. The optimal schedule and duration of how to give bisphosphonates in the clinical setting has yet to be defined.
Read more about the EBCTCG trial.
Circulating Tumor Cells Help Predict Survival Outcomes in Metastatic Breast Cancer
Researchers confirmed in the phase III SWOG S0500 trial that knowing a woman’s level of circulating tumor cells (CTCs), breast cancer cells that travel through the bloodstream, can help doctors predict overall survival. In clinical trials, overall survival is measured as the time from joining the study to death from any cause.
SWOG S0500 originally set out to explore whether changes in the level of CTCs in a woman’s blood would help oncologists make treatment decisions. The investigators designed the study to see if switching women whose CTC level remained high after a first round of chemotherapy to a different chemotherapy medicine would increase the amount of time she lived without the disease growing or spreading, or overall.
If this worked, women with metastatic breast cancer would be transitioned to new chemotherapies earlier than dictated by radiographic imaging, shielding them from the toxic side effects of therapies that did not work.
Unfortunately, the trial team found that the women who switched chemotherapies based on high CTC levels did as well as the women who stayed on their original chemotherapy, not better. This means that the current methods of measuring how well a treatment is working — screening and watching for disease progression, along with asking women about the severity of side effects — are still the best way to manage metastatic breast cancer. The CTC test does not help in making treatment decisions.
The finding that the level of CTCs may forecast how well a woman will do with metastatic breast cancer may, however, help doctors identify which women should begin treatment with standard chemotherapy and which may want to consider joining clinical trials testing new, unapproved medicines earlier on.
If you are in treatment for metastatic breast cancer, you and your doctors will work together to make the best treatment decisions for you, based on how the cancer and your body responds to your current treatments.
Talk openly with your healthcare team about how you feel on each treatment. Remember that it’s OK to ask questions about what treatment your doctors recommend.
Read more about SWOG S0500.