The Alphabet Soup That is Breast Cancer

BRCA. PBM. TNBC.  HER+.  PR+.  ER-. DIEP.  So much lingo, so many acronyms.  Breast cancer has its own language.  I’ve spent the past several months learning to speak it, and it’s still overwhelming.  But I need to understand the lingo to make informed decisions.

Recently I decided to do some research on the different types of breast cancer.  I’ve seen commercials on TV for drugs that treat metastatic breast cancer, HER2+ cancer, triple negative breast cancer (TNBC)—what does all this mean?

I’m going to try to break it down, and then figure out what it means to me.

Breast cancer tumors are often “fed” by hormones, specifically estrogen and progesterone.  A breast cancer tumor has receptors that “catch” these hormones, feeding the tumor and causing it to grow.  A tumor that feeds off these hormones is known as hormone receptor positive.  A tumor that feeds off estrogen is known as estrogen-receptor positive (ER+); a tumor that feeds off progesterone is known as progesterone-receptor positive (PR+).  A tumor that does not feed off these hormones is referred to as hormone-receptor negative (HR-).

Why is this relevant?  If your cancer is ER+ or PR+, drug treatments are available to eliminate the hormone from your body, effectively cutting off the food supply.  These treatments have been found to be very effective in treating hormone-fed breast cancers.

In addition to hormone-fed tumors, doctors will look for something called a HER2 gene in the tumor.  Cancers that have too many copies of the HER2 gene produce too much of the growth-producing protein also called HER2.  These cancers are known has HER2+ cancers.  Like ER+ and PR+ cancers, drug therapies are available to shut down the HER2 protein, cutting off the supply to the tumor and killing the cancer cells.

How wonderful it is that we have effective treatments for cancer!  RIGHT?

That fact that doctors can figure out what causes a tumor to grow allows them to tailor treatment to the type of cancer.  According to the Mayo Clinic, a patient with ER+, PR+, and/or HER+ breast cancer will benefit from drug therapies that target estrogen, progesterone, and HER proteins, respectively, cutting off the “food supply” to the tumor and ultimately killing the cancer cells.  You’ve probably heard of some of these drugs.  For example, Tamoxifen blocks estrogen.  Aromatase inhibitors such as Femara and Arimidex are progesterone blockers.  Herceptin and other drugs are used to treat HER2+ cancers. 

But what about a patient with ER-, PR-, HER- cancer?  This kind of cancer is known as triple negative breast cancer (TNBC).  Cutting off estrogen, progesterone, or HER2 won’t be effective in treating the cancer because they are not feeding the tumor.  These tumors tend to grow and spread faster than hormone-positive cancers, with fewer treatment options.  They are more likely to return after initial treatment, and outcomes are poorer compared to other types of cancer.  Surgery and chemotherapy are the only treatments for TNBC and are generally used in combination.  There are some drug therapies, such as Lynparza and Keytruda, that are used to treat TNBC, but these are used for advanced-stage cancers only.  At that point, the overall prognosis is already poor.

What does this mean for me?

TNBCs account for about 10%-15% of all cancers.  They are most common among African American women, women younger than age 40, and women with BRCA1 mutations.  Even more concerning, women with BRCA1 mutations are more likely to develop TNBC than other types of breast cancer; about 70% of cancers in BRCA1 patients are triple negative.

I have an 87% chance of getting breast cancer.  And about 70% of people like me who get cancer get the most aggressive, hardest to treat kind, which can only be treated with chemo and surgery.  That means that I have a 61% likelihood of developing TNBC at some point in my life. Those are some scary, scary numbers.

And that is why I’m coming to the realization that prophylactic surgery may save my life.