Neoadjuvant endocrine therapy 'a reasonable option' for ER-positive breast cancer

By Shreeya Nanda

Endocrine therapy should be reconsidered as a potential option in the neoadjuvant setting for localised oestrogen receptor (ER)-positive breast cancer, say the authors of a meta-analysis.

The analysis, published in JAMA Oncology, comprised 3490 patients drawn from 20 randomised trials that had at least one arm evaluating neoadjuvant endocrine therapy and reported response rates.

The researchers found that in the neoadjuvant setting, endocrine monotherapy with aromatase inhibitors (AIs) was comparable to combination chemotherapy with respect to the rates of clinical and radiological response, pathological complete response (pCR) and subsequent breast-conserving surgery (BCS). But toxicity was significantly lower with endocrine therapy than with chemotherapy.

Moreover, endocrine therapy with AIs versus tamoxifen resulted in significantly improved rates of clinical and radiological response and BCS, with odds ratios (ORs) of 1.69, 1.49 and 1.62, respectively. The pCRs rates did not differ significantly between women who received AIs and those given tamoxifen, but the investigators point out that "the total number of events was small and only 3 studies reported pCR".

They also highlight that "conclusions regarding improved rates of BCS are limited overall because determining eligibility for BCS is subjective by nature and depends on several variables, including patient preference."

Comparison of neoadjuvant endocrine therapy given either as monotherapy or in combination with another agent, such as everolimus, celecoxib or lapatinib, showed that clinical response rates were similar, but the radiological response rate was significantly better with dual therapy (OR=1.49).

The findings were similar when endocrine monotherapy was compared with dual therapy incorporating a growth factor pathway inhibitor - the clinical response rate was not improved with dual therapy, but the radiological response rate was significantly higher (OR=1.59).

Lead author Aditya Bardia (Massachusetts General Hospital Cancer Center, Boston, USA) and co-researchers, therefore, conclude: "Neoadjuvant endocrine therapy is a reasonable treatment option for localized [ER-positive] breast cancer, and additional studies are needed to develop rational endocrine therapy combinations and predictive biomarkers to optimize [neoadjuvant endocrine therapy] strategies."

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