Close to 30% of new cancer cases in American women each year are breast cancer, and experts estimate that 1 in 8 women in the United States will develop invasive breast cancer in their lifetime. Yet mortality rates from breast cancer have continued to decline dramatically in recent decades as treatment options expand and increased screening has also led to more early diagnosis.
Although a cancer diagnosis can be scary regardless of the stage, Endeavor Health oncologist and breast cancer specialist Anshu Hemrajani, MD, provides hope and encouragement, highlighting exciting developments in therapeutics for all three of the major types of breast cancer.
Major breast cancer classifications
Understanding the specific type of breast cancer is essential for creating a customized treatment plan:
- Estrogen receptor-positive breast cancer: The most common type that accounts for close to 80% of breast cancers
- HER2-positive breast cancer: Breast tumors that overexpress the HER2 protein
- Triple-negative breast cancer (TNBC): Tumors that don’t contain estrogen receptors, progesterone receptors, or excess HER2 protein
Both HER2-positive and triple-negative breast cancers tend to be more aggressive than estrogen receptor-positive cancers, but new therapies are bringing improved outcomes and greater numbers of cancer survivors across the board, said Dr. Hemrajani.
Advances in targeted therapies
Targeted therapies that attack estrogen receptor- or progesterone receptor-positive cancers are now commonly used after and in addition to traditional treatments, including surgery, chemotherapy and/or radiation.
These drugs were first used in later stage cancers but are now in play for earlier stage cancers, which have been shown to further reduce the risk of cancer coming back.
More recently, there have been developments in SERDs (selective estrogen receptor degraders) which are better tolerated than traditional anti-estrogen medications, while further reducing the risk of cancer recurrence.
“New targeted therapies are being released every year, and we are combining treatment approaches with two or three drugs to work on different pathways, and getting good results,” said Dr. Hemrajani.
The latest in antibody-drug conjugates
Antibody-drug conjugates (ADCs) were once used as later options for stage IV cancers, but are now being used as first line treatment and are often proving more effective than traditional chemotherapy.
“In the last year there have been three different studies in HER2 and triple-negative cancers that show that using an ADC by itself or in combination with other drugs has great benefit for these more aggressive late-stage cancers,” said Dr. Hemrajani.
There are also studies looking at ADCs as a replacement to chemotherapy in early-stage cancers, either before or after surgery, she added.
Immunotherapy and genetic testing
Immunotherapy has been the standard of care for stage II and III TNBC for a few years, and has been shown to significantly improve outcomes.
Parallel advances in genetic analysis have transformed diagnostic accuracy:
- Improved germline genetic testing has led to the recognition of genetic mutations that help clinicians determine how best to treat certain cancers and predict how aggressive certain cancers will be.
- Testing for somatic mutations in tumor cells (not in individual DNA) is now one of the first things physicians do to determine if there are specific mutations that can be targeted with specific therapies.
“It’s overwhelming, in a very good way, to have so many new drugs. It’s an exciting time to be treating breast cancer patients and we’ll continue to learn more and work to determine the best sequence of therapies for each type of cancer. It’s really transforming how we practice,” added Dr. Hemrajani.
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