Treatment Of Palbociclib In Hormone Receptor Positive Breast Cancer: A Real-world Study And Efficacy Prediction Model

ObjectiveThis research summarized the clinical use of palbociclib and evaluated its efficacy and safety.Methods1.We retrospectively analyzed data from advanced breast cancer patients treated with palbociclib and endocrine therapy in department of oncology in Jiangsu Province Hospital between August 30,2018 and August 30,2020.2.We assessed the factors affected the efficacy of palbociclib with log-rank test for monofactor analysis and cox regressions for multivariate analysis.3.Nomogram model was built for predicting prognosis among patients who received palbociclib,using concordance index(C-index),calibration curve,and area under curve(AUC)of receiver operating characteristic(ROC)for internal validation to assess the predictive ability and conformity of the model.ResultsAmong 66 patients treated with palbociclib,33.3%(22/66)patients were treated in first-line,42.4%(28/66)and 24.2%(16/66)patients in second and third lines.36.4%(24/66)patients had hepatic metastasis.16.7%(11/66)patients were sensitive to previous endocrine therapy;27.3%(18/66)patients had primary resistance to endocrine therapy,while 56.1%(37/66)patients had secondary resistance to endocrine therapy.The overall response rate(ORR)was 14.3%(9/63,95% confidence interval [CI]:6.7%～25.4%)and clinical benefit rate(CBR)was 58.7%(37/63,95%CI:45.6%～71.0%).Log-rank analysis revealed that better clinical outcomes were associated with nonhepatic metastasis(p=0.001),sensitive/secondary resistant to previous endocrine therapy(p=0.004),none or only one line of chemotherapy for metastatic breast cancer(p=0.004),recent pathological confirmation of immunohistochemical analysis(p=0.025),but they were not related to palbociclib setting groups as followed: age,menopausal status,weight,body mass index(BMI),body surface area(BSA),metastatic status at diagnosis,disease-free interval,estrogen/progesterone receptor percentage,Ki67 index,visceral/bone/lung/brain metastasis,surgery for metastatic sites,and drug withdrawal/reduction for adverse effects.Multivariate analysis indicated that hepatic metastasis and primary resistance to endocrine therapy were the independent risk factors of progression free survival and nomogram was built and verified to have good predictive ability for prognosis.ConclusionOur report indicated that the patients treated with palbociclib who had hepatic metastasis and primary resistance to endocrine therapy had worse prognoses,while the patients were well-tolerated.The constructed nomogram could help predict the survival and provide assistance to the use of palbociclib.