A wee drab

Breast Cancer Risk (Gail Model) Calculation Methods

The halls.md detailed breast cancer risk calculator offers a choice of two calculation methods, called "Gail model 1" and "NSABP model 2". If you are curious, you can compare the results of my calculator to some other calculators. You’ll find that my results are close, very close, not exactly the same, but not significantly different.

The NCI has a website version of the Breast Cancer Risk Assessment Tool. Their calculator should be considered the most authoritative and accurate standard. The results of my NSABP model 2 calculator differ slightly from the NCI’s tool, because of programming technique differences. (their link was formerly at http://bcra.nci.nih.gov/brc/ )

The Gail model is named after Dr. Mitchell H. Gail, who (along with other colleagues) published several famous papers describing the scientific basis for the risk calculation. The NSABP stands for National Surgical Adjuvant Breast and Bowel Project. It is a big organization that has conducted many important research studies. The NSABP used the original Gail model and modified it for a research study. That is why I call it NSABP model 2. (2014 update. It eventually became called Gail2 model.) You can read more about NSABP model 2 in this news article

Keep in mind why I made the calculator in the first place. Dr Gail published in 1989, but ordinary people couldn’t use the methods. I was frustrated.

Even in 1999, only a few NSABP clinical trials, and only principle investigator oncologists, were allowed to use the “Risk Disk”, which was a program to calculate risk on a CD rom disk. This frustrated me, because radiologists and family doctors and patients were also highly interested in knowing about risks. So, I read the published articles, and figured out a way to make a working calculator, and put it publically on the internet.

The nci.nih.gov website put their own risk calculator onto the internet, later in the same year, 2000. My results were extremely close to theirs, and my calculator is much quicker, so I left it and was proud of it. My calculator was designed to recalculate automatically whenever you change a pop-up menu item (if you entered your age). It becomes educational to experiment with the menu choices, and instantly see the effect on risk.

Any problems?

I was very frank in saying that my method was not published in a peer-reviewed journal. But it was certainly based on reading journal publications, and I think status-conscious gov and edu websites of the world avoided linking to me as a result. But thank-goodness for popularity.

I also know that individual doctors, and nurses from all over the world, are using my calculator on a daily basis. 15 years of use.

What’s happened since then?

In December 2014 while changing the style of the website, I searched for other calculators, and there were none. Only mine and NCIs.

Hundreds of great scientific articles have been published on all sorts of risk factors, but none of those extra risk factors have been added into the NCI’s risk calculator.

Why not?

Everyone is busy busy busy. The top-level statisticians are hard to find. The gigantic population study would have enormous cost.

Until they do update, at least people can get an estimate on the halls.md site.

If you need a serious assessment and discussion of your personal risk, I recommend you contact a professional risk assessment service, or discuss it with your own doctor.

Click here to continue to read a detailed description of how the breast cancer risk calculator was designed.

Back to the Breast Cancer Risk Calculator. Or, I have a whole different website filled with Breast Cancer Information.