New findings released Sunday at the 50th annual meeting of the American Society of Clinical Oncology focused on methods to treat hormone-sensitive breast cancers in premenopausal women and to manage HER2-positive early-stage disease.
Aromatase Inhibitors for Young Women
Pooled findings from two large phase III clinical trials suggest young women with estrogen-receptor positive early-stage breast cancer who stop the activity of their ovaries may have an option beyond tamoxifen.
An analysis of the trials, called SOFT and TEXT, looked at the role of different types of hormonal therapy in preventing cancer from coming back for women in this age group.
The trials showed that an aromatase inhibitor, a type of medicine that is FDA approved for postmenopausal women, is also effective for premenopausal women when combined with ovarian suppression, treatment that keeps estrogen from flowing throughout the body in women who still get their periods.
At a late-breaking abstract session, Olivia Pagani, MD, clinical director of the breast unit at the Oncology Institute of Southern Switzerland, revealed part of this major multinational study. Results were published online in the New England Journal of Medicine.
Women in the study were put into menopause with a shut-down of their ovaries, using either surgery, medicine or radiation. The women were then randomly assigned to receive 5 years of daily treatment with either the standard tamoxifen or an aromatase inhibitor called exemestane (Aromasin). A third group received tamoxifen for 5 years but did not have ovarian suppression; this group’s results were not reported at the meeting.
Treatment with exemestane plus ovarian suppression over 5.7 years reduced the risk of any invasive cancer by 28 percent and reduced the risk of breast cancer coming back by 34 percent. There was no significant difference between the two groups in survival rates over 5 years. Women who took the AI had a greater risk for bone health problems, vaginal dryness, and lack of interest or pain during sex.
Nancy Davidson, MD, of the University of Pittsburgh Cancer Institute, said though these results are promising, she does not plan to recommend that young women take aromatase inhibitors until she sees results of the tamoxifen-only portion of the SOFT trial, which should come by the end of this year. She also noted she wants to review long-term follow-up results and better understand the role obesity may play.
If you are a premenopausal woman with early-stage breast cancer, talk with your doctor about how to weigh the advantage of taking an AI against possible side effects. Dr. Pagani noted that 14 percent of women dropped out of the trial because of side effects.
Treatment for HER2-Positive Breast Cancer Fails Test
Results for another major trial surprised and disappointed the breast cancer scientific community. A late-breaking abstract reported on combinations of two anti-HER2 therapies – lapatinib (Tykerb) and trastuzumab (Herceptin) – in early-stage disease.
Lapatinib, a treatment approved for metastatic breast cancer, is used when the standard trastuzumab has stopped working effectively. A previously reported trial, NeoALTTO, showed that adding lapatinib to trastuzumab before chemotherapy increased the chances of the cancer shrinking in early-stage disease.
The phase III trial reported today, called ALTTO (Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization trial), asked whether adding lapatinib to trastuzumab could delay or prevent cancer from coming back after surgery more effectively than trastuzumab alone. Martine J. Piccart-Gebhart, MD, PhD, director of medicine at the Jules Bordet Institute, in Brussels, Belgium, reported it did not.
After surgery and along with chemotherapy, women received either lapatinib only; trastuzumab only; trastuzumab followed by lapatinib; or both medicines at the same time. The lapatinib-only group was stopped early when it failed to show positive results. Researchers found that neither the combination nor the sequence was more effective than trastuzumab alone. Including lapatinib also added side effects such as rash and diarrhea.
Although disappointing, the negative trial results help keep researchers from spending resources on treatments that don’t work, speakers said.
Look on lbbc.org for more updates throughout the meeting and in the coming weeks, and learn more about our free webinar covering findings from ASCO, to be held noon to 1 p.m. ET on Tuesday, June 24.