Metastatic breast cancer is advanced-stage breast cancer that has spread to parts of the body away from the breast, such as the bones or the liver. Metastatic breast cancer usually is considered treatable but not curable.
Still, a small study found that 9% of women diagnosed with HER2-positive, metastatic breast cancer that was treated with chemotherapy and the targeted therapy Herceptin (chemical name: trastuzumab) were in remission for at least 3 years. Remission means there was no detectable cancer. Doctors call remission this long a durable remission. The study was presented at the September 2011 European Multidisciplinary Cancer Conference (ECCO-ESMO).
Herceptin is used to treat advanced-stage, HER2-positive breast cancer and to lower the recurrence risk of early-stage, HER2-positive breast cancer with a high risk of recurrence (the cancer coming back). HER2-positive cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive. Herceptin works by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin often is used in combination with chemotherapy to treat advanced-stage breast cancer. Herceptin is given intravenously.
The researchers looked at the outcomes of 120 women diagnosed with metastatic, HER2-positive breast cancer. All the women were treated with a combination of Herceptin and chemotherapy between May 2000 and April 2011. Many of the women were receiving Herceptin continuously for a number of years -- half for more than 5 years. Half the women had 6.5 years of follow-up information; fewer years of follow-up information was available for the other women.
Eleven women (9%) had a durable response to treatment: remission for 3 years or longer. A durable response was more likely if the cancer had spread only to the liver and not to other parts of the body. It seems that receiving Herceptin for an extended period of time made long-term remission possible. Many advanced-stage cancers become resistant to treatment, such as chemotherapy, over time. This study suggests that some metastatic, HER2-positive breast cancers will respond to Herceptin for a long time, making long-term remission possible.
If you've been diagnosed with advanced-stage, HER2-positive breast cancer, you might want to talk to your doctor about this study and what the results might mean for your treatment plan. You can learn more about Herceptin and Tykerb (another targeted therapy for advanced-stage. HER2-positive breast cancer) by visiting the Breastcancer.org Targeted Therapies pages.