Treatment for HER2-positive early breast cancer has changed significantly over the past several decades. Today, HER2-targeted therapies are an important part of treatment for many people, helping improve outcomes for a cancer that was once much more difficult to treat.
Researchers are asking an important next question: Can we make treatment more personalized?
Rather than giving every patient the same treatment, could doctors eventually use characteristics of each tumor to determine who needs more treatment, who might safely need less and who is most likely to respond to a particular approach?
That is one of the areas of research that Dr. Sara Hurvitz, a medical oncologist and breast cancer researcher, is watching closely.
The right treatment for the right patient
For people with HER2-positive early breast cancer, treatment may involve chemotherapy and HER2-targeted therapy before surgery. This approach, known as neoadjuvant therapy, can shrink the tumor and provide an important opportunity to see how the cancer responds.
After treatment, surgery can show whether any invasive cancer remains.
When no invasive cancer is found in the breast or lymph nodes at surgery, doctors call this a pathologic complete response (pCR).
A pCR can be an encouraging sign that the cancer responded well to treatment. But researchers want to know whether they can predict that response before treatment even begins.
What is HER2DX?
HER2DX is a genomic test being studied in people with early-stage HER2-positive breast cancer.
The test combines information about the tumor’s biology with clinical factors. Its 27-gene approach incorporates signals related to areas including immune response, tumor cell growth, luminal differentiation and HER2 biology, along with tumor size and lymph-node status. Research has shown that HER2DX can provide information about both the likelihood of achieving a pCR and the risk of recurrence.
Dr. Hurvitz describes the test as potentially providing information about “how likely a patient is who has HER2-positive breast cancer to have a pathologic complete response with their HER2 targeted therapy.”
In other words, could a test taken before treatment help doctors estimate how likely the cancer is to completely respond to therapy?
Could HER2DX help predict treatment response?
In a recent analysis of more than 2,500 people with early-stage HER2-positive breast cancer, those considered low risk by HER2DX had a 93.6% chance of being free from a breast cancer event six years later, compared with 82.9% for those in the high-risk group.
The results were consistent across different cancer stages, lymph-node involvement, hormone receptor status and treatment responses. This suggests HER2DX may provide information beyond standard factors such as tumor size, stage and pathology results.
The hope, Dr. Hurvitz explains, is to eventually use information like this to “tailor a patient’s therapy” and better match treatment intensity to each person’s risk.
Could this lead to less chemotherapy?
This is one of the biggest questions researchers are trying to answer.
Dr. Hurvitz explains, in the future, “if the score is really good, maybe use less chemo or shorter duration of therapy,” while patients with a higher-risk score might need a more intensive approach.
The goal would not simply be to give people less treatment. Instead, it would be to avoid unnecessary treatment while making sure people at higher risk receive enough therapy to reduce their risk of recurrence.
For some patients, reducing chemotherapy could mean fewer short-term side effects and potentially fewer long-term effects. For others, identifying a higher-risk cancer could help doctors determine when a more intensive treatment approach may be appropriate.
Researchers still need clinical trial evidence to show that using HER2DX to make those treatment decisions is safe and improves outcomes.
What does the research mean for patients today?
Dr. Hurvitz emphasizes that HER2DX remains under investigation. “This is still under heavy investigation,” she says. “I’m not using it in clinical practice since I don’t think it’s endorsed by the guidelines to be used in clinical practice.”
The test has undergone additional analytical validation showing reproducible performance across laboratories and testing conditions, and clinical studies continue to evaluate its ability to predict response and outcomes.
However, research is still needed to determine whether using HER2DX to select less-intensive or more-intensive treatment actually improves patient outcomes.
What should patients know about clinical trials?
For patients who are interested in participating in research, a clinical trial may offer an opportunity to help answer questions about how HER2-positive breast cancer should be treated in the future.
Dr. Hurvitz encourages both investigators and patients considering clinical trials to participate in research that can help validate these approaches.
If you’re interested in a clinical trial, ask your oncology team whether there are studies appropriate for your specific stage, HER2 status, and treatment plan.
Disclaimer: The information provided in this article is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Outcomes4Me is not acting as your caregiver, and any suggestions or guidance offered should not replace the advice of your healthcare provider or qualified medical professional. Always seek the guidance of your physician or other qualified health provider with any questions you may have regarding a medical condition.
