Neoadjuvant endocrine therapy may be just as effective as neoadjuvant chemotherapy for patients with localized, estrogen-receptor (ER)-positive breast cancer with considerably fewer adverse events, according to a study published in JAMA Oncology.
ER-positive tumors of the breast have been shown to be highly responsive to targeted endocrine therapies; however, the role of these treatments in the neoadjuvant setting is still unclear.
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In a study led by Laura Spring, MD, Massachusetts General Hospital Cancer Center (Boston, MA), researchers compared the effect of neoadjuvant endocrine therapy with neoadjuvant chemotherapy on the response rate and rate of breast conservation surgery for patients with ER-positive breast cancer.
The analysis included 20 studies of 3490 unique patients reporting response rates with at least 1 arm incorporating neoadjuvant endocrine therapy. Overall, researchers found that neoadjuvant monotherapy with aromatase inhibitors had a similar clinical response rate, breast conservation surgery rate, and radiological response rate compared with combination chemotherapy, but with lower toxicity.
Further, the use of aromatase inhibitors significantly improved clinical response and radiological response compared with tamoxifen, another type of endocrine therapy, while dual combination therapy with growth factor pathway inhibitors was only associated with improved radiological response, not a higher response rate, compared with endocrine monotherapy.
Researchers concluded that neoadjuvant endocrine therapy was associated with similar response compared with neoadjuvant combination chemotherapy, but with significantly lower toxicity. Treatment with endocrine therapies should be considered in this setting when treating patients with ER-positive breast cancer, though more research is needed to develop predictive biomarkers and make it easier for clinicians to personalize optimal neoadjuvant strategies for these patients.
"Endocrine therapy is an approved option for neoadjuvant treatment of localized estrogen-receptor-positive breast cancer,” Dr Spring said in a press statement released along side the study. “So there's no reason our findings cannot be applied to treatment right now."
