Women diagnosed with early-stage, HER2-positive breast cancer who were treated with adjuvant chemotherapy followed by Herceptin (chemical name: trastuzumab) for 1 year were 24% less likely to have the cancer come back (recur) compared to women who got adjuvant chemotherapy but no Herceptin.
Treatments given after surgery to reduce the risk of recurrence are called adjuvant treatments.
The research was published in the journal Lancet Oncology.
HER2-positive breast 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. HER2-positive breast cancers tend to be more aggressive and harder to treat than breast cancers that are HER2-negative.
Herceptin is a targeted therapy medicine that treats HER2-positive breast cancers by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin, given intravenously, is approved by the U.S. Food and Drug Administration to:
- treat advanced-stage, HER2-positive breast cancers
- lower the risk of recurrence of early-stage, HER2-positive breast cancers with a high risk of recurrence
These results are from the most recent analysis of the Herceptin Adjuvant (HERA) trial. More than 5,000 women diagnosed with early-stage, HER2-positive breast cancer are participating in HERA.
Besides surgery (followed by radiation therapy in many cases), all of the women got chemotherapy, either before surgery (neoadjuvant chemotherapy), after surgery, or both before and after surgery. After chemotherapy was done, the women were randomly chosen to get either Herceptin or placebo (a sugar water infusion). After 1 year of follow-up, an early analysis showed the women who got Herceptin had a 46% lower risk of recurrence compared to those who didn't get Herceptin. Because these early results were so promising, HERA ended early in 2005 and the women who didn't get Herceptin could start Herceptin if they wanted to (called crossing over); many of them chose to start Herceptin.
The latest HERA analysis includes more than 4 years of follow-up, comparing the outcomes of women who got 1 year of adjuvant Herceptin to women who got the placebo.
Nearly 79% of women who got adjuvant Herceptin were alive with no recurrence (disease-free survival) compared to 72.2% of women who didn't get adjuvant Herceptin. This difference in disease-free survival is a 24% lower risk of recurrence among the women who got adjuvant Herceptin.
Recurrence risk in the women who decided to get 1 year of adjuvant Herceptin after they got the placebo (the women who crossed over) was 32% lower than recurrence risk in women who never got adjuvant Herceptin.
More than 89% of the women who got adjuvant Herceptin were alive after 4 years, whether or not they had a recurrence (overall survival) compared to 87.7% of the women who didn't get adjuvant Herceptin.
This difference in overall survival wasn't significant, which means that it could have been due to chance and not because of the difference in treatment.
Women treated with Herceptin sometimes had serious side effects (called grade 3 or 4 adverse events), including:
- heart failure
- high blood pressure
- joint pain (arthralgia)
- back pain
- intravenous catheter infection
- hot flashes
Still, these side effects were seen in only 1% of the women who got Herceptin.
This HERA analysis confirms the benefits of adjuvant Herceptin after chemotherapy to treat early-stage, HER2-positive breast cancer. Other research suggests that giving Herceptin at the same time as adjuvant chemotherapy might reduce the risk of recurrence more than giving Herceptin after chemotherapy. But more research is needed to figure out if giving Herceptin with chemotherapy is a better approach than the current standard of giving Herceptin after chemotherapy.
In the Breastcancer.org Targeted Therapy section, you can learn more about how Herceptin works, when it is used, and what to expect during treatment.