Breast Surgery May be Unnecessary for Appropriately Selected HER2+ Patients in the Future

Abstract: Patient Selection for Non-Operative Management of HER2+ Invasive Breast Cancer after Neoadjuvant Systemic Therapy

Dallas, May 2, 2019–Tumor hormone status, possible DCIS on initial biopsy and imaging results following neoadjuvant chemotherapy (NCT) may help physicians predict whether surgery may be safely eliminated for traditionally aggressively treated HER2+ breast cancer in the future.
These were the findings of a new study comparing the clinicopathologic characteristics of HER2+ patients who had no evidence of residual cancer on a pathology report following NCT with those who did. NCT is chemotherapy delivered prior to primary traditional surgical treatment to help optimize the intervention. The study was presented here at the annual meeting of the American Society of Breast Surgeons.
“More than 56,000 cases of HER2+ breast cancer, a comparatively aggressive tumor, are diagnosed in the U.S. annually,” says lead researcher Susie Sun, MD, University of Texas MD Anderson Cancer Center. “Evidence is growing that certain patients are exceptional NCT responders, suggesting that when properly identified someday certain of these women may be candidates for non-operative treatment.”
Dr. Sun points out, however, that confirmation of NCT response using traditional medical imaging is often inconclusive, with a high rate of false negatives, making identification of appropriate patients difficult. “Our study shows that hormone receptor positive disease, presence of DCIS at diagnosis and inconclusive imaging results following neoadjuvant chemotherapy correlated with an incomplete response to NCT, suggesting these women must go on to surgical treatment,” she explains.
The study examined 280 patients with HER2+ breast cancer treated with NCT followed by surgical resection. Multivariate analyses were performed to determine predictors of residual disease. Of the 280 patients, 102 (36.4%) had a pathologic complete response (pCR) to NCT in both the breast and lymph node.
Patients with incomplete pathologic response were more likely to have hormone receptor positive compared with negative tumors (73.4% vs. 50.8%; respectively, p<0.0001). Also correlating with residual disease in the breast and nodes was incomplete radiologic response (OR 5.62, p=0.002), meaning that radiologists were unable to rule out residual disease.
DCIS was found in 129 (46.1%) patients on initial biopsy. Of these, 32 (24.8%) had residual DCIS only following NST. The therapy failed to eradicate in situ disease in 64.3% of patients. Women with both invasive disease and DCIS on initial biopsy were less likely than those without DCIS to achieve pCR in the breast (31% vs. 43%, p=0.038). Post-NCT imaging had a sensitivity of 97.1% and negative predictive value of 70.6% for residual cancer.
“This study is particularly important right now because it may help identify optimal patients for ongoing clinical trials omitting surgery for carefully selected HER2+ patients,” comments the study’s principal investigator, Henry Kuerer, MD, PhD, FACS, University of Texas MD Anderson Cancer Center. “Findings are extremely important because of the inability of medical imaging to reliably confirm the absence of cancer following initial NCT. They help delineate the types of HER2+ tumors that should not be included in our trials.”
“No one wants to have surgery unnecessarily,” says Dr. Sun. “This study and the clinical trial may help us delineate in the future which patients may be effectively treated non-operatively, while allowing us to provide more aggressive surgical intervention to the women with HER2+ breast cancer who need it.”