Although there are drugs that specifically target HER2-positive breast cancer, often its treatment is even more personalized, with disease characteristics influencing whether a patient undergoes surgery or takes medications, explained Dr. Arielle J. Medford, a hematology/oncology fellow at the Dana-Farber Cancer Institute in Boston.
She recently discussed the management of HER2-postivie breast cancer at the CURE® Educated Patient® Metastatic Breast Cancer Summit and in an interview with us said that it “is critical to know” HER2 status “because it’s such a driver of breast cancer and…such a targetable piece of the breast cancer puzzle,” adding that “there are therapies that patients can benefit tremendously from, so all patients should be tested for (status).”
Surgery or Therapy: Which First?
The time at which a patient receives therapy — before of after surgery — frequently depends on the size of the tumor.
For those that are very small (2 centimeters or less), patients may undergo surgery first to remove the cancer and for those that are bigger, or when the disease has spread, the best plan is usually to receive targeted drugs upfront.
“There’s so much benefit to be gained from giving the therapies first,” Medford said. “Those tumors tend to be very sensitive to HER2-targeted therapy, so it can be a smaller surgery, which is great.”
She also mentioned that giving drugs first also provides a “real-time” look at how the disease responds to treatment.
Targeting HER2-Positive Disease
Years ago, HER2-positive breast cancer was typically an aggressive disease with poor survival outcomes. Then in 1998, the Food and Drug Administration (FDA) approved Herceptin (trastuzumab), an agent that attaches to the HER2 proteins found on cancer cells and stops their growth.
“In fact, (Herceptin) was one of the very first personalized targeted therapies in all of oncology, not just breast cancer,” Medford noted.
In 2012, the FDA gave the green light to another HER2-targeting drug: Perjeta (pertuzumab), for use in combination with Herceptin and docetaxel in patients with HER2-positive metastatic breast cancer.
Medford also explained the impact that antibody drug conjugates like T-DM1 (ado-trastuzumab emtansine) and T-DXd (trastuzumab deruxtecan) had on patients with HER2-positivie breast cancer.
These types of drugs deliver chemotherapy directly to cancer cells, leaving surrounding healthy cells virtually untouched and thus decrease the severity of side effects typically seen with chemotherapy.
“We want patients to have a high quality of life,” Medford said. “We could not give that to patients before antibody drug conjugates because (the chemotherapy) caused too much toxicity.…Now we can give these really effective chemotherapies to just the cancer cells, which is huge.”
Looking forward, Medford said that she is optimistic about where the treatment of HER2-positive breast cancer is headed: “It’s a very exciting time” because “the field is continuing to rapidly expand.”
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