RESUMO
PURPOSE: In advanced breast cancer, endocrine therapy is preferred in the absence of visceral crisis. Cyclin-dependent kinase inhibitors (CDKi) are the gold standards. The selection of subsequent treatments after CDKi treatment is still controversial, and the efficacy of everolimus (EVE) combinations is unknown. In this study, we aimed to investigate the efficacy of EVE after CDKi administration in real-life experiences. METHOD: The study received data from 208 patients from 26 cancer centers. Demographic and histologic features, diagnosis, progression, last visit dates, and toxicities were recorded. This study was a retrospective case series. RESULTS: One hundred and seven patients received palbociclib, while 101 patients received ribociclib as a CDKi. The overall response and disease control rates of EVE combinations were 60% and 88%, respectively. In univariate analysis, the absence of liver metastasis, age > 40 years, better type of response, and immediate treatment after CDKi were related to increased progression-free survival. Liver metastasis and response type were significantly associated with overall survival. In the multivariate analysis, response remained significant in terms of progression-free survival, while response type, liver metastatic disease, and hematologic toxicity were prognostic in terms of overall survival. CONCLUSION: This study provides evidence of the benefits of EVE combinations after CDKi treatment. EVE combinations may be more appropriate for patients with non-liver metastasis, and the first treatment response shows the benefit of treatment. In addition, immediate treatment after CDKi treatment is more beneficial than later lines of treatment.
RESUMO
The only phase 3 study on the effectiveness of CDK 4-6 inhibitors in first-line treatment in premenopausal patients with hormone receptor (HR) positive, HER2 negative metastatic breast cancer is the MONALEESA-7 study, and data on the effectiveness of palbociclib is limited. Data are also limited regarding the effectiveness of CDK 4-6 inhibitors in patients whose dose was reduced due to neutropenia, the most common side effect of CDK 4-6 inhibitors. In our study, we aimed to evaluate the effectiveness of palbociclib and ribociclib in first-line treatment in patients with premenopausal metastatic breast cancer and the effect of dose reduction due to neutropenia on progression-free survival. Our study is a multicenter, retrospective study, and factors affecting progression-free survival (PFS) were examined in patients diagnosed with metastatic premenopausal breast cancer from 29 different centers and receiving combination therapy containing palbociclib or ribociclib in the metastatic stage. 319 patients were included in the study. The mPFS for patients treated with palbociclib was 26.83 months, and for those receiving ribociclib, the mPFS was 29.86 months (p = 0.924). mPFS was 32.00 months in patients who received a reduced dose, and mPFS was 25.96 months in patients who could take the initial dose, and there was no statistical difference (p = 0.238). Liver metastasis, using a fulvestrant together with a CDK 4-6 inhibitor, ECOG PS 1 was found to be a negative prognostic factor. No new adverse events were observed. In our study, we found PFS over 27 months in patients diagnosed with premenopausal breast cancer with CDK 4-6 inhibitors used in first-line treatment, similar to post-menopausal patients. We did not detect any difference between the effectiveness of the two CDK 4-6 inhibitors, and we showed that there was no decrease in the effectiveness of the CDK 4-6 inhibitor in patients whose dose was reduced due to neutropenia.