Are there any benefits to continuing trastuzumab after disease progression in patients with HER2+ metastatic breast cancer?

This article evaluated the benefits of continuing trastuzumab treatment after disease progression in patients with HER2+ metastatic (spread to distant organs and tissues) breast cancer.

Breast cancer cells have on their surface some proteins called receptors. Hormones bind to these receptors causing changes in the cells, which can lead to breast cancer. There receptors are: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Breast cancers which have HER2 are called HER2-positive (HER2+) breast cancers and usually have a worse prognosis than other types of breast cancer because they are more difficult to treat. Treatment of HER2+ breast cancers involves drugs that specifically target the HER2 protein, such as the drug trastuzumab (Herceptin). Treatment with trastuzumab, with or without conventional chemotherapy, has significantly improved survival in HER2+ breast cancer patients. However, breast cancer can become resistant (no longer responds to treatment) to trastuzumab. If the cancer progresses (continues growing) while on this treatment, there are few recommended therapies then to follow.

This article looks at data from 29 studies which included 2618 patients with HER2+ metastatic breast cancer. All these patients were treated initially with chemotherapy and trastuzumab for their metastatic disease, but the cancer had later progressed. They had undergone further trastuzumab treatment after disease progression.

Results were combined together from all patients in these 29 studies. Overall, patients treated with trastuzumab after progression of metastatic breast cancer had an average time to further disease progression of 7 months and the average overall survival (defined as the time patients survived since treatment) for these patients was 24 months. 

In conclusion, this article shows that continuing trastuzumab treatment with chemotherapy after disease progression improved survival in patients with metastatic HER2+ breast cancer.

However, this article did not compare trastuzumab treatment to different drugs that target HER2. Also, it does not discuss the possible side effects that may arise from the prolonged treatment with trastuzumab.

Talk to your doctor if continuing trastuzumab treatment is a good option for your situation.