In March, I attended a session on hormone receptor positive breast cancer at the Young Survival Coalition Summit. This was my first YSC Summit, and it was awesome! I met amazing women who are living beyond breast cancer, and I learned a lot about various topics. I especially liked the session on hormone receptor positive breast cancer (also known as ER/PR-positive breast cancer) because it covered the recent findings from the SOFT trial. This clinical trial compared three different treatments for early stage ER/PR-positive breast cancer.
What Is Hormone Receptor Positive Breast Cancer?
First, let me provide some background information. Not all breast cancers are the same. As I explain here, your tumor’s pathology lists the traits that characterize your cancer. These traits, called tumor markers, tell us whether the cancer is growing fast or slow and what factors promote its growth.
One of the markers we look at is the hormone receptor status. It tells us what percentage of the cancer cells have receptors for the hormones estrogen and/or progesterone. If at least 1% of the cells test positive for estrogen receptors, then your tumor is ER+. If they test positive for progesterone receptors, then it is PR+. Some cancers, like mine, are both ER+ and PR+. According to my pathology report, 84% of the cells are ER+ and 5% are PR+. The key here is that hormones fuel the growth of hormone receptor positive breast cancers.
Interesting fact: about two thirds of breast cancers are hormone receptor positive.
Why Do We Care About Hormone Receptor Status?
Knowing your cancer’s hormone receptor status is important because there are treatments available that either reduce hormone levels or block hormones from attaching to the receptors. This prevents or slows down the cancer’s growth. These treatments are called hormone therapy or endocrine therapy.
The standard endocrine treatment for early stage ER/PR-positive breast cancers differs according to the woman’s menopausal status. Premenopausal women receive up to 10 years of Tamoxifen. This drug blocks estrogen from binding to breast cancer cells. Women who are postmenopausal get five years of an aromatase inhibitor (AI) or a combination of Tamoxifen and an AI. While the ovaries of women who have been through menopause don’t make estrogen, their fat tissue does convert the aromatase enzyme into small amounts of estrogen. Aromatase inhibitors block this process.
Some doctors also treat hormone receptor positive breast cancer in premenopausal women by shutting down their ovaries. This is called ovarian function suppression, and it can be done by removing the ovaries or through injections of Lupron (leuprolide) or Zoladex (goserelin). Women who suppress their ovarian function also take Tamoxifen or an AI. This is not a standard treatment, but some studies have looked at its effectiveness.
At the YSC Summit, I learned that endocrine therapy is highly effective for treating hormone receptor positive breast cancer. Also, the higher your percentage of ER/PR positive cells, the more you will respond to the treatment.
SOFT Trial: Recent Research Findings
The SOFT trial is a study that took several years to complete. It was conducted to determine whether suppressing ovarian function for premenopausal women with early stage, hormone receptor positive breast cancer confers any benefits in terms of disease free survival (DFS). DFS is the length of time after primary treatment that a person lives without recurrence. The results became available last year, and they were discussed at the YSC session on ER/PR-positive breast cancer.
My takeaway from the session was that there are benefits to using ovarian suppression plus tamoxifen or an AI in two subsets of women: those who are 35 years old or younger and those who remained premenopausal after chemotherapy.
- Women who are 35 and under – At five years, the DFS rate was 67.7% when given Tamoxifen alone, 78.9% when given Tamoxifen plus ovarian suppression, and 83.4% when given an AI plus ovarian suppression.
- Women who are premenopausal after chemotherapy – At five years, the DFS rate was 78.0% when given Tamoxifen alone, 82.5% when given Tamoxifen plus ovarian suppression, and 85.7% when given an AI plus ovarian suppression.
Of course, these improvements in DFS come with the added burden of side effects. Ovarian function suppression renders you menopausal, so you will experience related symptoms. Possible side effects include hot flashes, depression, vaginal dryness, and decreased libido. Additionally, AI’s are associated with more joint pain and osteoporosis. Overall, most women reported that the side effects were tolerable, but more women dropped out of the AI group due to side effects.
Using This Information To Make Treatment Decisions
Last year, my oncologist encouraged me to shut down my ovaries through Lupron injections even though Tamoxifen is the standard of care. I hesitated because I don’t want to take additional medications unless I absolutely have to. However, I now believe that for a woman like me — 35 at diagnosis and premenopausal even after chemo — it makes sense to consider ovarian function suppression if I can tolerate the side effects.
I followed my doctor’s advice and began taking the Lupron shots last summer in addition to Tamoxifen. I figured I could always quit the shots if new research indicated otherwise or if the side effects were too toxic. I experienced hot flashes, which I could bear, but I also began breaking out in patches of eczema. The eczema worsened, so I halted the shots in November. We resumed them in January, and this time I’ve had no problems with my skin. Go figure…
Taking the shots every three months is a hassle though, so I also considered ovarian suppression through an oophorectomy. This is where attending the YSC Summit in March was super helpful. I spoke with other women who had their ovaries removed. I learned about their experiences and how the surgery has affected their lives. I’ve since decided against the oophorectomy because it could really worsen my quality of life, and it is permanent. With the shots, I can always stop and things go back to the way they were. I’ve also decided to continue taking the Tamoxifen rather than switching to an AI. I don’t think that the added benefit of the AI is worth the added risk of osteoporosis.
Making these decisions is complicated, and they come with a lot of uncertainty. There are many factors to consider, but I am glad to have options and access to information. At the end of the day, I try to choose avenues that will give me both peace of mind and quality of life.