Real-world outcomes of fulvestrant as first-line treatment of postmenopausal women with advanced breast cancer.

This study investigated the effectiveness of fulvestrant (Faslodex) as a first-line treatment for postmenopausal women with estrogen receptor-positive (ER+) metastatic breast cancer (BC) in a real-world setting. The data showed that the outcomes of these patients in the real-world setting were similar to clinical trials with manageable side effects.

In advanced BC the cancer has spread to the lymph nodes and other tissue in the breast or to other sites in the body. Many BCs grow in response to the female hormone estrogen through a protein present on cancer cells called an estrogen receptor (ER). This type of cancer accounts for 70% of all BCs. Patients with this subtype of BC commonly receive hormonal treatment (HT). HT blocks the action of the female sex hormone estrogen on the ER. Therefore, the cancer stops growing or spreading.

Fulvestrant is a HT. It reduces the number of ERs on BC cells and changes their shape, therefore, stopping their activity. Several clinical trials have demonstrated the effectiveness and safety of fulvestrant alone and in combination with other drugs, for the treatment of ER+ advanced BC. However, in clinical trials, patients are carefully selected to be fit and without additional medical conditions. Therefore, the effectiveness of fulvestrant as a first-line treatment for postmenopausal women with ER+ metastatic BC in real-world patients is not known.

This study involved 128 postmenopausal women with ER+ advanced BC. All of them received fulvestrant as first-line treatment for an average of 14 months. The average follow-up time was 31.4 months.

The average survival without disease progression) was 14.6 months.

The overall response rate (partial or complete response to the therapy) was 35.2%. Overall, 82.8% of the patients had a clinical benefit (response to treatment or stable disease). The average overall survival was 43.1 months with fulvestrant treatment.

8.6% of the patients reported a serious side effect such as respiratory problems, gastrointestinal or liver-related problems.

This study concluded that fulvestrant showed similar clinical benefits in a real-world setting with manageable side effects as a first-line treatment for postmenopausal women with ER+ advanced BC.

The sample size was small and the study looked back in time at medical records. Information might have been incomplete. Also, there was no comparison group. The study was funded by Astra Zeneca, the manufacturer of fulvestrant.