In a nutshell
This study investigated the clinical factors that influence patient response to trastuzumab (Herceptin) therapy in human epidermal growth factor receptor 2 positive (HER2+) metastatic breast cancer (MBC). Hormone receptor (HR) status was found to be a possible predictor of a strong response to trastuzumab-based therapy.
Trastuzumab is the main treatment option for HER2+ breast cancer. However, patients with HER2+ breast cancer may also have other factors driving cancer growth, such as hormone receptors. In HR positive (HR+) breast cancer, the hormones estrogen or progesterone can increase cancer growth. Patients who are HER2+/HR+ tend to have lower rates of remission (no sign of disease) than patients who are HER2+/HR negative (HR-).
Only 10% of HER2+ MBC patients experience a lasting response of more than 3 years. The role of HR status in HER2+ treatment response is not well known.
Methods & findings
This study included 153 women with HER2+ MBC who were treated with trastuzumab and either paclitaxel (Taxol) or docetaxel (Taxotere) as their primary treatment. The patient’s HR status and metastases were reviewed. Average follow-up time was 28 months with an average age of 52 years. Progression-free survival (PFS; time from treatment until disease progression) and overall survival (OS; time from treatment until death from any cause) were measured.
HR- patients showed a longer average PFS (19 months), compared to HR+ patients (9 months). The OS of HR- patients was 37 months. HR+ patients had an OS of 47 months.
Bone metastases were also associated with a longer PFS (15 months) and OS (75 months) than metastases to internal organs which showed a PFS of 11 months and OS of 34 months.
The bottom line
The study concluded that HR status is a possible predictor of outcome in patients with HER2+ MBC who receive trastuzumab-based therapy. Sites of metastases were found to independently influence treatment response.
The fine print
This study relied on the use of patient records and used a small sample size. This means some selection bias may be present in the results. A larger study is needed to confirm the results.
Discuss with your doctor how HR status may affect your treatment.
Published By :
Breast Cancer Research and Treatment
Feb 27, 2017
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