Efficacy of six month neoadjuvant endocrine therapy in postmenopausal, hormone receptor-positive breast cancer patients – A phase II trial

BackgroundNeoadjuvant hormonal therapy (NHT) is playing an increasing role in the clinical management of breast cancer (BC) and may improve surgical outcomes for postmenopausal, oestrogen receptor (ER)-positive BC patients. However, there is currently no consensus on the optimal duration of NHT before surgery. Here, we present the outcomes of the TEAM IIA trial, a multicentre, phase II trial investigating the efficacy of six months of neoadjuvant exemestane in postmenopausal, strong ER-positive (ER+, ⩾50%) BC patients.Methods102 patients (stage T2-T4ac) were included in the study after exclusion of ineligible patients. Primary end-point was clinical response at 3 and 6 months as measured by palpation. Secondary end-point was radiological response as measured by magnetic resonance imaging (MRI), mammography and/or ultrasound. Linear mixed models (95% confidence interval (CI)) were used to compare changes in mean tumour size (in mm) between baseline, 3 and 6 months after the start of endocrine therapy. Conversion rates from mastectomy to breast conserving surgery (BCS) were evaluated.ResultsMedian age of all patients was 72 years (range 53–88). Overall response rate by clinical palpation was 64.5% in all patients with a final palpation measurement. Four patients had clinically progressive disease. 63 patients had both 3-month and >3-month palpation measurements. Overall response was 58.7% at 3 months and 68.3% at final palpation (>3 months). Mean tumour size by clinical palpation at T = 0 was 39.1 mm (95% CI 34.8–43.4 mm), and decreased to 23.0 mm (95% CI 18.7–27.2 mm) and 16.7 mm (95% CI 12.6–20.8) at T = 3 and T > 3 months, respectively (p = 0.001). Final radiological response rates at the end of treatment for MRI (n = 37), ultrasound (n = 77) and mammography (n = 56) were 70.3%, 41.6% and 48.2%, respectively. Feasibility of BCS improved from 61.8% to 70.6% (McNemar p = 0.012).Conclusion6 months of neoadjuvant exemestane therapy helps reduce mean tumour size further in strongly ER-positive BC patients without significant side-effects compared to 3 months. Nevertheless, some patients still experience disease progression under exemestane. Feasibility of breast conservation rates improved by almost 10%.