Pre- vs. Postmenopausal Breast Cancer Risk: There’s a Difference, But Does It Matter?

You’ve probably seen those plastic breast self-exam cards you hang on your showerhead as a reminder to feel for lumps on a monthly basis. I have one myself, and would read it over and over when I was trying to decide whether my lump was worrisome, reviewing the “reduce your risk” tips the card offered.

However, there are two points that I wasn’t aware of at the time that I was diagnosed: (1) we know little about causal factors, as most studies that examine risk are only correlational; and (2) there’s a difference between being premenopausal vs. postmenopausal when talking about breast cancer.

Okay, there’s a third one too: (3) risk factors don’t mean squat when I’m talking about my personal diagnosis.

First, a well-known fact: postmenopausal women make up the majority (approximately 2/3) of these cancer cases, so it’s not surprising that the focus is on them.

I, however, was premenopausal when I felt the lump in my left breast.

Imagine my surprise, then, when I learned that while being overweight or obese is a significant risk factor for postmenopausal women, being overweight as a premenopausal woman seems to offer protection against the disease. Whereas I thought I didn’t have any risk factors for breast cancer, as suggested by that plastic card in my shower, perhaps I did.

There’s not much talk about that protective element of weight for premenopausal women. You would be hard-pressed to find a popular website that mentions it. And no doctor would encourage a premenopausal woman to carry extra weight on the off chance that it might lower her risk of breast cancer; it’s too much of a liability for other health issues, including other cancers.

This explains why, if you’ve gone to a gathering of newly-diagnosed breast cancer patients, you’ll see some younger, remarkably fit women looking a little dazed and wondering what they’re doing there.

The weight risk factor is often posed in the following way (from the Mayo Clinic site): “Overweight and obese women have a higher risk of being diagnosed with breast cancer compared to women who maintain a healthy weight, especially after menopause.” Well, that’s not wrong, but it doesn’t tell the entire story.

Harvard Health Online puts it differently, with a caveat: “Being overweight or obese has been linked to breast cancer risk, especially for women after menopause, but the relationship is complicated. It may be that risk is increased in women who gain weight in adulthood but not in those who’ve been overweight since childhood.” That seems even more confusing and less reassuring.

It’s true that everything about cancer is complicated. If it were straightforward, we would have found a cure by now. Furthermore, when it comes to guidelines to follow, people don’t want details, they want sound bites. But simplification cuts out information. For example, this CDC webpage about what you can do to lower your breast cancer risk posts recommendations geared for older women, including maintaining a “healthy weight”, but the photo that’s shown is clearly of two younger women.

Even a cursory glance at the research reveals what a difference menopausal status makes. In addition to extra weight seeming to have a protective effect in premenopausal women (Cold et al., 1998, Eur J Cancer; Lahmann et al., 2004, Int J Cancer), it’s also been determined that greater red meat consumption in adolescence is significantly associated with increased risk of breast cancer in premenopausal women (Farvid et al., 2015, Int J Cancer). Interestingly, higher quality diets have a more beneficial effect on the risk of postmenopausal women and seemingly no effect on premenopausal ones (Haridass et al., 2018, J Nutr). I would expect that a more exhaustive search would yield even greater differences.

Live as if your life depends on it.

So what does this tell us? This is less about the specific differences between pre- and postmenopausal breast cancer risk, and more that there simply is a difference. At this point in our knowledge, we are still putting together pieces of the cancer puzzle.

Additionally, many studies that offer preventative guidelines are based on other studies–they may be meta-analyses of previously collected data from a broad range of subjects. The data may be self-reported, which may result in recall error. And when you have a sample size of ~30,000 women, you’re talking about general risks for populations, not a specific risk for a specific, and very unique, individual: you.

All this sounds exasperating, but one concept holds true: no matter what your risks, the healthier you are before you’re diagnosed with cancer, the better your outcome compared to someone with less healthful habits, should you get the disease. Instead of obsessing about possible risk factors, give yourself the respect you deserve–put the effort into improving lifestyle habits to grant yourself the best chance for survival. In the end, that’s what matters.

(Almost) Two Years on Tamoxifen: A Change in Plans

This weekend would have marked two years of taking tamoxifen, the estradiol-blocking medication that is supposed to keep my hormone-positive breast cancer from recurring.

As it turns out, there will be no such commemoration. Several weeks ago, I started noticing a funny cramping feeling in the general area of my uterus. It was light and under any other circumstances, I would have ignored it, but use of tamoxifen is associated with an increased risk of endometrial/uterine cancer, so it kept me on edge.

It’s worth noting that the increased risk is actually for postmenopausal women, and to the best of my knowledge, I was not yet postmenopausal. That’s why pre- and perimenopausal women are started on tamoxifen but taken off of it as soon as they go through menopause. Still the sensation, although intermittent, didn’t go away.

I finally called my oncologist. As it was, I was wary of tamoxifen – I already blamed it for a number of other negative things that I experienced: fatigue, hair thinning, low libido, cognitive issues, mood swings, general misery…all of those and more were listed as possible side effects.

I complained about the light cramping to an oncological nurse, who was surprised that I didn’t have a recent pap smear on record, because according to her, the oncologist wanted me to have one yearly. Mind you, pap smears are for cervical cancer, and I wasn’t at an increased risk for that. But whatever. The nurse gave me her blessing to stay off tamoxifen until I next saw the oncologist.

Conveniently, my oncologist appointment was in three days.

I was stressed, because if there’s one thing that being a cancer survivor made me good at, it was stressing. So much so, that my blood pressure hit 165/95 at my appointment. I couldn’t get over how ridiculous that was and how my thoughts had generated that sort of a reaction. I don’t think my pressure was even that high before my cancer surgery, at a time when my anxiety was raging and everything felt out of control.

I had a prolonged discussion (negotiation?) with my oncologist. In the end, we decided the following: I could take a month off tamoxifen and meet with him again in six weeks. In the meantime, I would go to my gynecologist to rule out endometrial cancer. (Incidentally, a week later at the gynecologist’s office my blood pressure was back down to a very reasonable 102/64.)

No more tamoxifen? Yeah, I feel like celebrating.

My oncologist and my clinical counselor (who I discovered had spoken to him about me) thought that some of the worst side effects that I was experiencing were not due to tamoxifen, but anxiety. My onc suggested that if nothing improved after a month off tamoxifen, I should consider anti-anxiety meds.

But he also checked my hormone levels to see where I was in my journey into menopause. A few days later, I got the news: I was officially postmenopausal and was told to not restart tamoxifen.

So, okay, no more tamoxifen. I was also quite happy that I managed to transition through menopause without any significant hot flashes. The downside of this was, however, that I would be put on an aromatase inhibitor, which came with its own set of side effects, not the least of which was significant bone pain and bone density loss.

Or at least those were some of the effects that I remembered from the last time that I read about them, which was a while ago. This time, I’ve decided, I won’t go back and research all the negatives of the medication. Anxiety does hit me hard, I have to admit, and I want to be sure that I’m really experiencing what I’m experiencing and not simply being influenced by what I’ve read.

So I’ll give the new medication a fair shake and give myself a break by not getting worked up by what *might* happen. As the gynecologist said, looking over my bloodwork, “Actually, you’re really healthy, except for having had breast cancer.” I’m going to go with that and see where it takes me.