You are here: Home / Areas of Care / The Marvelle Koffler Breast Centre / FAQs / Herceptin


What is Herceptin ® (Trastuzumab) ?

Herceptin ® (Trastuzumab) is a monoclonal antibody. Monoclonal antibodies are made in laboratories and are substances that can find and bind to cancer cells wherever they are in the body. Herceptin targets cancer cells that "overexpress" (makes too much of) a protein called HER-2/neu, which is found on the surface of the cancer cells. These cancers that overexpress HER-2/neu often grow more quickly and are more likely to recur (come back). Herceptin stops or slows the growth of these cells. HER-2/neu is overexpressed in 25-30% of all human breast cancers.

How did the researchers find out if Herceptin was effective ?

The use of Herceptin has been well establised in patients with metastatic breast cancer overexpressing HER-2/neu. More recently, the early results of three multicentre randomized trials have been presented at the American Society of Clinical Oncology assessing the use of Herceptin in the adjuvant setting for breast cancer (i.e. for the prevention of a recurrence). In these trials, women with HER-2/neu positive early stage breast cancer treated with chemotherapy were either randomized to receive or not receive Herceptin.Women who received Herceptin had a significantly lower rate of breast cancer recurrences when compared to those who did not receive it.

How do they know if my breast cancer was Her-2/neu positive ?

Testing is performed on cancer cells that have been removed during breast cancer surgery. It may also be performed on cells from a breast tissue sample that has been stored from a previous biopsy. Your cancer specialists will receive a report from the lab,if the test was carried out, indicating if your tumor is positive for Her-2/neu protein overexpression. This helps the doctor decide if you would benefit from treatment with Herceptin.

Can a woman with Her-2/neu positive breast cancer get Herceptin in Ontario ?

Based on the results from recent trials, Herceptin is now funded in the province of Ontario for Her2/neu positive breast cancer patients with node positive or node negative (tumour greater than 1 cm in size) primary breast cancer who are or have received adjuvant or neoadjuvant chemotherapy, effective August 1st 2005. If you have been diagnosed with HER2/neu positive breast cancer and treated with chemotherapy on or after November 1st 2004, you may be eligible to receive Herceptin and should discuss this further with your treating oncologist (cancer specialist).

Written by Dr. Louise Bordeleau MD, FRCP (C) , Medical Oncologist and an Assistant Professor of Medicine at the University of Toronto