Anti-HER2 Th1 Response Superior to MRI in Assessing Chemo Response in HER2-Positive Breast Cancer: Presented at SSO

By Nancy Melville

BOSTON -- March 7, 2016 -- The presence of high anti-human epidermal growth factor receptor 2 (anti-HER2) T-helper type 1 (Th1) immune response is a stronger predictor than magnetic resonance imaging (MRI) of pathologic response to neoadjuvant chemotherapy in HER2-positive breast cancer, according to a study presented here on March 3 at the 69th Annual Cancer Symposium of the Society of Surgical Oncology (SSO).

“We found that immune response demonstrated strikingly accurate diagnostic metrics compared with post-treatment MRI,” said Lucy M. De La Cruz, MD, University of Pennsylvania, Philadelphia, Pennsylvania. “This assay has considerable promise and validation in a large-scale study is warranted.”

In determining response to neoadjuvant chemotherapy in HER2-positive breast cancer, MRI is considered the gold standard, with a specificity of 90.7% but a low sensitivity of 63.1%.

With previous research from Dr. De La Cruz’s team linking ant-HER Th1 response with pathological response following the chemotherapy, the authors expanded the research, identifying 30 patients with HER2-positive breast cancer and anti-HER2 Th1 data who had received neoadjuvant chemotherapy had post-treatment MRI.

Among them, 13 (43.3%) achieved complete pathologic response. Of those, the mean anti-HER2 Th1 response was remarkably higher (154.5), compared with those with less than complete pathologic response (23.4), with distributions that had little to no over-lapping.

Dr. De La Cruz noted that the findings were consistent with previous reports showing that low anti-HER2 Th 1 responders, with levels <50, are more likely to be a non-pathologic complete responders on final evaluation, while anti-HER2 Th 1 response of ≥50 is associated with a greater likelihood of having a complete pathologic response.

In a blinded review of a further subset of 28 patients, diagnostic outcomes with MRI remained inferior to anti-HER2 Th 1 response, with a false negative rate of 38.8% with MRI compared with 0% with anti-HER2 Th 1, and a false positive rate of 50% compared with 0.7% with anti-HER2 Th 1, for a sensitivity of 41.7% versus 100.0% and specificity of 2.5% versus 94.1%, respectively.

The results remained similar among patients stratified by oestrogen receptor status.

“Identifying complete pathologic response can help tailor subsequent medical and surgical interventions and potentially in the future even avoid surgery, but this can only be done if it can be determined preoperatively with a high level of sensitivity and specificity,” Dr. De La Cruz said.

“The presence of ‘high’ anti-HER2 Th 1 response is superior to the use of post-treatment MRI in the assessment of pathologic complete response in HER2-positive breast cancer in this pilot study,” she said.

[Presentation title: Anti-HER2 Th1 Response Is Superior to Breast MRI in Assessing
Response to Neoadjuvant Chemotherapy in Patients With HER2-Positive Breast Cancer Abstract 22]

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