Molecular imaging offers glimpse into treatment response for HER2-positive breast cancer
Molecular imaging may offer a more targeted approach to treatment in patients with HER2-positive breast cancer who are undergoing chemotherapy.
HER2-positive tumors account for around 20% to 25% of breast cancer cases and are known to often be more aggressive. Neoadjuvant therapy is commonly used before surgery to shrink tumors, but determining early on whether treatment is working remains challenging. Although MRI is the standard modality for monitoring treatment response in these patients, distinguishing residual tumor from treatment-related fibrosis can be difficult.
A new study published in the Journal of Nuclear Medicine suggests that the use of a PET/CT molecular imaging agent—68Ga-HER2—may address this gap by accurately predicting the response after just two treatment cycles. Experts involved in the research suggest these findings may give providers a better idea of how patients will respond to treatment in the long-term and enable them to adjust treatments much earlier if necessary.
“These findings provide preliminary prospective evidence that changes in HER2-targeted tracer uptake can predict treatment response at a very early stage,” Xinming Zhao, MD, PhD, director of the Department of Nuclear Medicine at the Fourth Hospital of Hebei Medical University and Hebei Provincial Tumor Hospital in China, said of the new data. “For patients, the potential importance is that treatment response may be assessed much earlier.”
The prospective study evaluated gallium-68–labeled HER2 PET/CT in 44 patients with biopsy-confirmed, HER2-positive breast cancer. Researchers assessed whether changes in tracer uptake could predict pathologic complete response following neoadjuvant treatment. Patients underwent 68Ga-HER2 PET/CT at baseline, after the second treatment cycle and before surgery. All patients received at least four cycles of neoadjuvant therapy, although treatment regimens varied.
Baseline imaging did not distinguish patients who ultimately achieved pathologic complete response from those who did not. However, changes in tracer uptake after two treatment cycles were associated with outcomes at surgery; patients whose primary tumor tracer uptake decreased by at least 61% after the second cycle had an 85% rate of pathologic complete response, compared with 38% among patients whose uptake declined by less than 61%.
The findings suggest that HER2-targeted molecular imaging may offer an early measure of treatment response by directly assessing changes in HER2 expression within tumors. If validated in larger studies, the approach could provide additional information to help clinicians discuss treatment options and surgical planning earlier in the care pathway.
“If future studies confirm our findings, imaging could provide earlier information to support discussions about alternative treatment strategies or surgical timing,” Zhao added.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.