What is this summary about? This summary describes the results from a real-world study called POLARIS and includes effectiveness results (previously published online in The Oncologist in October 2024) and patient-report outcomes (previously published online in Breast Cancer Research and Treatment in November 2024). This study assessed and followed patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2–) advanced breast cancer (ABC) receiving palbociclib with hormone therapy. POLARIS included patients whose breast cancer could not be cured with current treatments, including those who had advanced breast cancer that had spread beyond the breast and lymph nodes or metastatic breast cancer. Data from real-world studies, such as POLARIS, are used to confirm and complement the results of traditional clinical trials. Patients were followed from the start of treatment and up to 3 years after treatment was stopped. The researchers wanted to see how palbociclib was used in routine clinical practice to treat patients. They checked if the treatment worked well by looking at the length of time patients lived without their cancer getting worse, and how long they lived from the start of treatment to the end of the study. They also wanted to know how patients perceived their quality of life while taking palbociclib.
What were the results? This study showed that in routine clinical practice, most patients received palbociclib as a first-line treatment for their ABC. Aromatase inhibitors were the preferred type of hormone therapy given with palbociclib. The length of time that half of the patients lived without their cancer worsening was 18.8 months, and the length of time that half of the patients lived after starting treatment was 42.3 months. Patients who received palbociclib as a first-line treatment lived longer without their cancer worsening compared with patients receiving palbociclib as a second-line (or later) treatment. Patients also reported that their quality of life remained the same from when treatment first started up to 18 months after treatment. The greatest improvements in quality of life were seen in patients’ ability to carry out daily tasks and in their experience of pain. These data collected from the real-world setting were similar to findings reported from clinical trials of palbociclib.
What do the results mean? This real-world study shows that treatment with palbociclib given in routine clinical practice worked well for a broad group of patients. Those receiving palbociclib as a first-line treatment generally had better outcomes than those receiving palbociclib as a second-line (or later) treatment. Patients’ quality of life remained stable over 18 months, with slight improvements in daily activities and pain. Overall, these results support findings from clinical trials and other real-world studies, showing that palbociclib plus hormone therapy is effective for treating people with HR+/HER2– ABC with little noticeable impact to patient’s quality of life. Clinical trial number: NCT03280303.