Risk Reduction from Tamoxifen..did I figure this right?

kec1972

If my risk of recurrence is 10% assuming 5 years of tamoxifen, and I'm premenopausal so tamoxifen reduces my risk say 40%, then my risk without tamoxifen would be 16%...is that correct? Of course I will check with my MO in a few weeks but I just wanted to check here.

Beesie

Yes, that is correct (with rounding to the numbers to make whole numbers).

edj3

Hey Beesie, what formula is used for that, and does it change for post menopausal women (who in this case is me and I can't take aromitase inhibitors).

Beesie

edj3, I didn't use a formula, I just used the assumptions that kec1972 provided and rechecked the math.

edj3

Ah rats! Was hoping for a formula I used an online calculator which shows my risk as really low. Just a way to distract myself as I wait for the MammaPrint results.

kec1972

Thank you Beesie! The assumption is tamox reduces risk 30-40% in premenopausal and 40-50% in postmemopausal.(this is what I've garnered from my extensive research on the drug).

Beesie

kec, is that any recurrence or metastatic recurrence?

When I was first diagnosed 13+ years ago, I had bookmarks with all the research study data on Tamox. But because the drug is so old now, none of the sites are active anymore. I have top line results from the studies, but have been unsuccessful so far at digging around for the detailed data that I want.

kec1972

I believe distant recurrence

kec1972

Not sure if a 6% potential decrease is worth all the headaches ofvtamoxifen

Mimasw3474

I’ve tried letrozol and exemestane with horrible side effects. Had to stop taking them. My Onc put me on tamoxifen and I’m having horrible muscle cramps. I’m taking it every other day because I can’t handle every day. I’m fatigued and nauseous. I’m about ready to stop it but I’m scared.

Ingerp

kec--keep in mind it depends on how you look at the probability reduction--in absolute or relative terms. 16% down to 10% can be viewed as a 6% reduction, or <more appropriately> as a 40% reduction in the probability of recurrence, as you stated in your original post. That is really significant. (And just to be picky, that 16.666666 would round to 17%. ;-) )

edj3

Ingerp, I think the number you cite (40% reduction in probability of recurrence) is a little misleading.

Let's say my risk is 10% and I take tamoxifen (which is the drug my MO recommended since I have osteopenia and have already broken my pelvis from it), and my risk is cut by 50%.

Now I go from a 1 in 10 chance to 1/2 in 10 chance of recurrence (assuming the best possible outcome). That's just not a huge change IMO. Sure, relatively speaking it's a 50% drop. But it's a 5% drop--not that big actually. And for sure not one that immediately tips me toward taking them as I make my own decision about hormone blocking drugs.

edwards750

I didn’t hesitate to take Tamoxifen because frankly I was afraid not to. I wanted that extra insurance in trying to prevent a recurrence. Having said that I didn’t have unmanageable SEs like a lot of women have. According to my Oncotype report I have an 8% chance of a recurrence with taking Tamoxifen for 5 years. My Oncotype score was 11.

I know ladies who have either refused the drug or quit taking it when it literally made their QOL a living hell. They are fine many years later so you never know.

Do what you think is best for you- that’s the most important thing. I know doctors get all bent out of shape when a patient decides to go against their recommendations but it isn’t their life - it’s yours.

Diane

Ingerp

edj--the 40% was from the original post.

Beesie

Yes, but in the original post, edj was using the 40% relative risk reduction to determine the absolute risk reduction that she will get from Tamoxifen, which is a 6 point benefit.

The 40% is a necessary part of the mathematical equation, but I agree with edj that it's the absolute benefit that we each need to consider when we make our decision on whether or not to take endocrine therapy. The 40% relative risk reduction would work out to be a 2 point benefit for one person (whose risk of mets without endocrine therapy is 5%) and a 12 point benefit for another person (whose risk of mets without endocrine therapy is 30%). Quite the difference, when measuring these benefits against the risk and side effects from the Tamoxifen itself. This is why the 40% on it's own is misleading.

I would say that the absolute benefit (6 points, for edj) is the appropriate way to assess the benefit of endocrine therapy vs. the relative benefit (a 40% reduction in risk). Absolute benefit is how my MO talks about all treatments.

kec1972

Yes, relative risk reduction means nothing. It's all about the absolute risk reduction. By the way, I chose 40% because for premenopausal women, tamixifen is slightly less effective(about 30-40%) than it is for postmemopausal women(40-50%). That's what I've come across in my research anyway. Beesie—did you take tamoxifen 13 years ago?