Forgive the old picture, but I don’t have any current pics of my meds. Because I don’t have any meds. Which is sort of a blessing and a curse. It’s great that I don’t have to remember to fill a prescription and remember to take a daily pill. It’s really great that I don’t have to deal with side effects. What’s not so great, you may be wondering? I’m not actively doing anything to help prevent a recurrence. If you know someone who’s had breast cancer and finished her treatment, odds are good that she’s taking a pill every day for the next five or ten years, and so it’s an obvious question to wonder why I’m not.
And this is where we go back to the science. Remember when I explained about how my breast cancer is called triple negative? (Yep, if you look at that post, I used the same picture! Sorry!) Pathologists look at three main receptors when classifying breast tumors: ER, PR, and HER2. Since my tumor didn’t have any of the three, I am considered “triple negative.” Tumors that express ER or PR are considered hormone responsive, and they make up 60-70% of newly diagnosed breast cancer cases. These tumors use estrogen to grow, which means that shutting down their ability to use estrogen can shut down tumor growth. No tumor growth means your tumor won’t kill you. Obviously, hormone-targeted therapies have made a significant impact in the management of hormone responsive tumors. There are several ways to manage hormone responsive tumors long term. Tamoxifen is the most commonly known, and it acts as an anti-estrogen in the breast and effectively shuts down estrogen signalling. Other drugs (raloxifene, toremifene, and fulvestrant) work in a similar manner. Aromatase inhibitors halt the production of estrogen (letrozole, anastrazole, and exemestane) and can also be used to starve the tumor of estrogen. (Fun fact– a woman’s body uses testosterone to make estrogen using an enzyme called an aromatase, so aromatase inhibitors prevent that conversion). In premenopausal women, ovarian ablation (with drugs like gosserelin or leuprolide) can be used in conjunction with aromatase inhibitors, and have recently been shown to be very effective. These treatment regimens are long term– five years used to be the standard, now some studies indicate ten years is even better– and are not always tolerated well. Like any treatment, some women don’t have many side effects, but for some women, the treatment causes significant quality of life issues leading them to choose to stop treatment. (This is certainly not a decision to be made without talking to your doctor! I’m just saying that it happens, good or bad…) Most women deal with some side effects that fall into the undesirable category, but are considered a reasonable trade off for the reduction in risk of recurrence.
All of that is to say that at least 60-70% of women treated for breast cancer benefit from long term hormonal treatment. But for those of us without hormone responsive tumors, there is no reason to take the meds. Our tumors don’t use the estrogen, so blocking it won’t help us. And herein lies the blessing and the curse. I don’t have to take daily meds and deal with the side effects, which is awesome. But I’m also left in the position where there is no medication that I can take that will reduce my risk of recurrence, and that’s a little less awesome. I’m just going to count on the fact that the chemo did its job and keep running, running, running. (I do wish it would warm up, though. It’s a little cold and icy to enjoy running right now!) I can’t take tamoxifen to help me, but exercise has been shown to reduce recurrence risk. And so I will run. As one triple-negative friend put it: “Running is my tamoxifen.”
For a more complete discussion on hormonal therapy for breast cancer, check out what this fact sheet from NCI (National Cancer Institute). It’s complete and not overly technical.