LBA14 Impact of age, recurrence score (RS) and ovarian function suppression (OFS) on endocrine response to short preoperative endocrine therapy (ET): Analysis of ADAPT and ADAPTcycle trials

Update Breast Cancer 2022 Part 5 – Early Stage Breast Cancer

“…Accordingly, these preliminary biomarker data from the ADAPT studies provide a good basis for further research on the concept of dynamic Ki-67. For premenopausal women in particular, these molecular data are consistent with the clinical results showing that the best disease-free survival times were achieved through treatment with aromatase inhibitors + OFS 36 ; this corresponds to the group that had the largest reduction in Ki-67 in the ADAPTCycle study 35 .…”

“…The highest response rates were seen in the postmenopausal patients treated with aromatase inhibitors (81.5 % in the ADAPT study and 77.9 % in the ADAPTCycle study), and in premenopausal patients treated with aromatase inhibitors + OFS (76.9 % in the ADAPTCycle study). Treatment with tamoxifen as monotherapy led to significantly lower response rates in both the postmenopausal patients (42.5-56.3 %) and the premenopausal patients (32.0-40.1 %) [35]. With regard to prognosis, it was shown that the Ki-67 response rate had a greater effect on the prognosis for patients aged 50 or under (HR = 0.63, 95 % CI: 0.24-1.65) than it did for patients aged over 50 (HR = 0.78; 95 % CI: 0.54-1.12).…”

“…4 . Data have been published for over 5900 patients in total (3666 from ADAPT1 and 2272 from ADAPTCycle) 35 . A particular point of interest was the response of hormone receptor-positive tumors depending on the patientʼs age and whether or not they received endocrine therapy.…”

“…▶ Fig. 5 Response rate (Ki-67 ≤ 10 % after endocrine therapy) in the ADAPT studies (data from [35]).…”

Recommendations for the diagnosis and treatment of patients with early breast cancer: update 2023

“…Preoperative short-term ET for 2–4 weeks can be used to predict the efficacy of endocrine therapy by the response of Ki-67. Endocrine therapy response should be considered in addition to gene expression testing for routine decision-making on chemotherapy use in HR+/Her2- N0-1 EBC [29].…”