Looking at the latest breast cancer treatments

The San Antonio Breast Cancer Symposium offers new insights into improved treatments options for breast cancer.

When treating hormone-sensitive early stage breast cancer, a key decision is how long a patient should remain on an estrogen blocker. Five years? Ten? Several studies have addressed this question, but the answer remains unclear.

The NSABP-B42 study looks at women who have completed five years of anti-estrogen therapy – either aromatase inhibitor (AI) or tamoxifen followed by AI. Women were randomized to an additional five years of AI vs. placebo.

There was a 4 percent absolute reduction in breast cancer recurrence with extended AI use but no difference in overall survival seen thus far. There was no increased risk of osteoporotic fractures with longer AI use.

The decision to continue anti-estrogen therapy beyond five years remains individualized based on the patient, risk of the tumor, bone density score and tolerance of the treatment. But we now have another important study showing a potential benefit of longer treatment, and researchers are investigating genomic assays that we hope will help guide treatment decisions.

We have seen several treatment advances for HER2-positive metastatic breast cancer. The symposium featured three important therapies that will soon, if not already, be available to treat patients. The Food and Drug Administration (FDA) granted accelerated approval for trastuzumab deruxtecan (Enhertu) on Dec. 20. The oral HER2-blocker tucatinib received FDA breakthrough designation on Dec. 18, based on improvement in overall survival, including patients with brain metastases. Finally, margetuximab (an anti-HER2 antibody) is awaiting FDA approval based on improvements in outcomes in combination with chemotherapy compared to trastuzumab (Herceptin) and chemotherapy.

Breast cancer is a complex disease, with treatment options varying between the stage and specific biology of an individual’s cancer. Decisions about therapy are becoming increasingly targeted to specific pathways, and molecular testing is continuing to evolve to better tailor treatments. We continue to see improved outcomes with better quality of life.

Please join me at 6:30 p.m. Feb. 19 at the Cancer Support Community, 3276 McNutt Ave., Walnut Creek, to hear more about new treatment strategies in breast cancer. Reservations recommended by emailing sgoldberg@dvohmg.com or calling 925-677-5041.

Dr. Svahn is a medical oncologist and breast cancer specialist with Diablo Valley Oncology and Hematology Medical Group in Pleasant Hill. She is the medical director of the Women’s Cancer Center of the East Bay. For more information, call 925-677-5041 or visit dvohmg.com.