If you or someone you love has HER2+ breast cancer, you’ll have a lot of questions. What will treatment look like? Will doctors be able to cure the cancer? How will it affect your quality of life?
One thing to keep in mind is that the numbers you find online can’t tell you about you or a loved one specifically. These numbers are averages based on many women who’ve found out they had breast cancer in the past. Because each woman is different, they can’t tell you exactly what will happen to you or any particular woman.
The chance of a cure or putting the disease into remission depends a lot on how advanced the cancer is when treatment starts. If it’s only in the breast, that’s much better than if it has already spread to other parts of the body. A cure or remission will depend on treatment and how well the cancer responds to treatment. The chances of survival also depend on your age and general health.
The fact that the cancer is positive for HER2 will affect your treatment and survival. Experts consider the HER2+ breast cancer to be more aggressive than some other breast cancers. That means it may grow faster without treatment. The good news is that treatment for the HER2+ type has improved, so the outlook for you or a loved one is likely better than what some of the numbers show.
Understanding Survival Rates
A survival rate tells you how many people with a given diagnosis survive. Survival rates for cancer often show how many people survived for 5 years. It’s usually a percentage. So a 5-year survival rate of 75% means that 75% of people with that diagnosis lived for at least 5 years after the diagnosis.
Sometimes you may also see something called a relative survival rate. Relative survival rates tell you how likely a person with a certain cancer type is to survive, compared to people who are the same age, race, and sex without that cancer type. For example, the National Cancer Institute’s database shows that a woman with breast cancer has a 5-year relative survival rate of 90%. In other words, the cancer lowers the chance of living for 5 years by 10%.
One thing to keep in mind is that these survival rates don’t tell you if a person still has cancer or not. Someone who lives for 5 years after a diagnosis might still be in treatment. The cancer might seem to go away and then come back.
Relative Survival Rates for Breast Cancer
The National Cancer Institute gives 5-year relative survival rates for breast cancer based on how far the disease had spread before a doctor found it.
- Localized (cancer is confined to one breast): 99%
- Regional (cancer has spread to nearby lymph nodes): 86%
- Distant (cancer has moved to other parts of the body): 28%
- Unknown stage: 55%
- 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. They also come from data that researchers collected from 2010 to 2016, so they don’t reflect more recent treatment advances.
Understanding HER2+ Status and Survival
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 (HR). When a cancer has none of these, doctors call it triple negative. Until recently, there wasn’t much information about how these markers changed survival rates for breast cancer.
A recent study looked at the National Cancer Institute data to see if there were differences in survival for women based on these markers. The study shows there are. Overall, women who have HR+ and HER2- breast cancer do best. But in the later stages, those who have the HER2+ type have better survival rates than those with HER2-. Breast cancers that are triple negative have the lowest survival rates. The 4-year survival rates are as follows:
- HR+/HER2-: 92.5%
- HR+/HER2+: 90.3%
- HR-/HER2+: 82.7%
- HR-/HER2-: 77.0%
HER2+ Status, Cancer Stage, and Survival
The importance of HER2 status for survival will depend on how far the cancer has spread. If it’s only in the breast, then it won’t make much difference. Most women in the early stage of the disease do well because a surgeon can remove the tumor.
It’s when a breast tumor grows and spreads to lymph nodes or farther away in the body that HER2 status becomes more important for treatment and survival. That’s because there are now drugs that target HER2, but these work only for cancers that are HER2+. A common drug for HER2+ breast cancer is trastuzumab (Herceptin), but there are others. Because there are more treatments, women with more advanced HER2+ breast cancers today will on average have better survival rates than those with more advanced HER2- breast cancers.
