Table of invasive bc per 1000 women for different factors

Lea7777

The biggest risk factor by far is atypical hyperplasia. LCIS is not specifically listed. Note about 60% down the table in the IR per 1000. Women that atypical hyperplasia is 13.1. That is far more than any other factor, even very dense breasts. The next closest risk factor is having 2+ relatives with bc and that is only 5.8. The article that accompanies the table is dated April 2018, located here

https://jamanetwork.com/journals/jamaoncology/fullarticle/2677301

Janeway69

Other interesting notes is how this clearly makes things more complex than some news stories would have you think.
Eg. We always hear about how women who never had a child or bore their first after 35 have a greater risk, and how excess body fat increases risk. Yet the number of invasive cases doesn't go up linearly for increasing BMI, and while one of the highest numbers of cases goes for nulliparous women, the highest number goes to a group that had their first child before 30.

Janeway69

So the IR is percentage?

Lea7777

So the IR is percentage?

IR looks like Incident Rate per 1000 women per year. 13.1 women with atypical hyperplasia get bc in a year. For a percent that would be 1.31% per year.

Lea7777

These figures do show some over estimation for those at highest risk and a little underestimation at the lowest work. The overestimation is greater when breast density is taken into account. Who is considered high risk? "the model identifies few women in the general population to be at high risk (taken to be an absolute 10-year risk of ≥8%)"

Observed and Expected Cumulative Invasive Breast Cancer Risk by Quantile

"The risk groups are from the predicted 10-year risk assessment (lowest decile, middle 80% and top decile). Solid lines indicate observed risk; broken lines, expected risk. At 10 years the observed risk for the Tyrer-Cuzick model and the Tyrer-Cuzick model with density was 1.4% and 1.0%, respectively, for the bottom decile of risk; 2.7% and 2.6%, respectively, for the middle 80% of risk; and 5.9% and 7.0%, respectively, for the top decile of risk."

Those at highest risk are shown in black/gray, no color. The solid line is actual cases of bc and the dotted line is expected cases based on the model. The way I read this for chart B that takes breast density into account is that after 19 years (that is how low the study went) about 13% of those at high risk got cancer. The T-C model predicted 15% would.

The Tyrer-Cuzick IBIS risk assessment tool can be found at

http://ibis.ikonopedia.com/