Please someone who;s better at math than I.....

mom3bunky, I can't figure out the math either and I always thought I was pretty good at it. Sometimes I think they pull these percentages out of thin air.

I am not a mathematician, but from what I have gleaned over the years, your chance of recurrence doubles without the antihormonal. Mine was 8% with Tamoxifen, so I am assuming about 16% without. However, I have had the BCI test and it shows an increased risk after 5 years so I will be on the drugs for at least 10 years.

I tried to just keep it as simple as possible and I still don't get it!! When I do the cancer math under therapy, I get 30% mortality without, shortens life expectancy by 6.1 yrs. With therapy I get 20.4% mortality and live 1.9 yrs longer. Onco score =17 I think 11% recurrence rate. I do another predict tool and get that I am getting 3% added benefit by taking the AI. I don't fully understand any of it, but with therapy the numbers are better, so....I put up with my hair falling out and no red wine ever due to the hot flashes.

Momtobunky, I think your MO must have said that if you don't take Tamoxifen, your risk will got up BY 30%. Very different than going up TO 30%.

To ceanna's example, a 30% increase would take a 10% risk up to 13.3%. This is consistent with what you've read from me on the board, based on the various studies I've seen.

To be picky on the numbers based on what the studies actually show, the math has to be a backwards calculation, starting with the risk level before the benefit of the risk reduction is applied. Therefore if your risk is 10% without Tamoxifen, and Tamoxifen is known to reduce risk by 30%, then your risk without Tamoxifen is 14.2%. Here's the math (with a little bit of rounding to stay within 1 decimal place):

Risk without Tamoxifen: 14.2%

30% of 14.2: 4.2 - risk reduction from Tamoxifen

14.2 - 4.2 = 10% risk if you take Tamoxifen

WC3, the only error is a slight mathematical one.

A 30% decrease or reduction is calculated by applying the 30% to the higher number. i.e. the number that is being decreased by 30%.

Therefore, if Tamoxifen reduces the risk of mets by 30%, it works like this:

- If the risk of mets without Tamoxifen is 10%, then with Tamoxifen, it's 7%, which is a 30% reduction of the 10%. 10 - 7 = 3, 3 is 30% of 10

- If the risk of mets when taking is Tamoxifen is 10%, then without Tamoxifen, it's 14.2%, because 10% is a 30% reduction of 14.2%. 14.2 - 10 = 4.2, 4.2 is 30% of 14.2

On the other hand, if a condition or activity increases risk, the increase is calculated by applying the % increase to the lower number, i.e. the number that is being increased.

I think we are getting too much in the weeds.

I agree with Beesie. One thing I do understand is the math and stats.

Beesie:

Thanks for the correction! My brain is a bit rusty.