How to Think About Survival Rates

If you or someone you love has HER2-positive (HER2+) breast cancer, you'll have a lot of questions. What will treatment look like? Will doctors be able to cure the cancer? Remember, the numbers you'll find online are averages based on many women who have had breast cancer. Because everyone is different, they can't tell you what will happen to you or any woman.

The chance of a cure or putting the disease into remission depends a lot on how advanced the cancer is when treatment starts, as well as your age and overall health. Experts consider HER2+ breast cancer to be more aggressive than some other breast cancers. That means it may grow faster without treatment. But treatment for HER2+ breast cancer has improved, so the outlook is likely better than what some of the numbers show.

The National Cancer Institute gives five-year relative survival rates for breast cancer based on how far the disease has spread. 

• Localized (cancer is confined to one breast): 99%
• Regional (cancer has spread to nearby lymph nodes): 86.7%
• Distant (cancer has moved to other parts of the body): 32%
• Unknown stage: 69.7%
• All stages: 90%

While these numbers can give you a general idea, they are an average for women with any type of breast cancer. They aren't specific to the HER2+ type.

Doctors use three markers to help define breast cancers and guide treatment. One of those is the HER2 protein. The other two are hormone receptors (HRs). A recent study looked at the National Cancer Institute data to see if there were differences in survival rates for women based on these markers. The study found that five-year survival rates are as follows:

• HR+/HER2−: 95.1%
• HR+/HER2+: 91.5%
• HR−/HER2+: 85.7%
• HR−/HER2−: 78.0%

Drugs such as trastuzumab, pertuzumab, and T-DM1 specifically target HER2 proteins to slow or stop cancer growth. These treatments have significantly improved survival rates across all stages of HER2+ breast cancer. For instance, trastuzumab has been shown to reduce the risk of recurrence by 40% in early-stage HER2+ breast cancer.

Research on HER2+ breast cancer treatment is ongoing, with new therapies continually being developed. Clinical trials are exploring combinations of existing drugs and testing new targeted therapies. These advancements offer hope for even better outcomes in the future.