1. Real-World Experience among Elderly Metastatic Breast Cancer Patients Treated with CDK4/6 Inhibitor-Based Therapy.
- Author
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O'Connor, Thomas N., Schultz, Emily, Wang, Jianxin, O'Connor, Tracey, Levine, Ellis, Knudsen, Erik S., and Witkiewicz, Agnieszka K.
- Subjects
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BREAST cancer prognosis , *THERAPEUTIC use of antineoplastic agents , *AROMATASE inhibitors , *RESEARCH funding , *BREAST tumors , *ANTINEOPLASTIC agents , *SCIENTIFIC observation , *TREATMENT effectiveness , *RETROSPECTIVE studies , *METASTASIS , *EXPERIENCE , *CANCER patient psychology , *PROGRESSION-free survival , *COMPARATIVE studies , *CYCLIN-dependent kinases , *SIGNAL peptides , *OVERALL survival , *EVALUATION , *CHEMICAL inhibitors , *OLD age - Abstract
Simple Summary: Although women 70 years of age and older represent a large percentage of newly diagnosed breast cancer cases, older individuals are drastically underrepresented in clinical trials. Most women diagnosed with breast cancer at 70 years of age and older present with hormone receptor-positive (HR+) breast cancer. Cyclin-dependent kinase (CDK) 4/6 inhibitor-based therapy has become the standard of care for metastatic HR+ breast cancer. This study reports that metastatic breast cancer patients ≥70 years of age receiving CDK4/6 inhibitor-based treatment, particularly when combined with an aromatase inhibitor, experience prolonged progression-free survival but display no such prolongation in overall survival and report more frequent adverse effects to treatment. The reported findings can aid in the development of optimized treatments based on age and help older patients weigh treatment options. The largest portion of breast cancer patients diagnosed after 70 years of age present with hormone receptor-positive (HR+) breast cancer subtypes. Cyclin-dependent kinase (CDK) 4/6 inhibitor treatment, in conjunction with endocrine therapy, has become standard-of-care for metastatic HR+ breast cancer. In total, 320 patients with metastatic breast cancer receiving CDK4/6 inhibitor combined with fulvestrant or an aromatase inhibitor were enrolled in an ongoing observational study or were included in an IRB-approved retrospective study. All patients receiving CDK4/6 inhibitor-based therapy that were ≥70 years of age (n = 111) displayed prolonged progression-free survival (27.6 months) as compared to patients <70 years of age (n = 209, 21.1 months, HR = 1.38, p < 0.05). Specifically, patients receiving a CDK4/6 inhibitor with an aromatase inhibitor who were ≥70 years of age (n = 79) displayed exceptionally prolonged progression-free survival (46.0 months) as compared to patients receiving the same treatment who were <70 years of age (n = 161, 21.8 months, HR = 1.71, p < 0.01). However, patients ≥70 years of age also experienced more frequent adverse responses to CDK4/6 inhibitor-based treatment leading to dose reduction, hold, or discontinuation than the younger cohort (69% and 53%, respectively). Treatment strategies that may decrease toxicity without affecting efficacy (such as dose titration) are worth further exploration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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