Understanding the Risk of Recurrence

One of the goals of breast cancer treatment is to prevent a future recurrence of the cancer (the cancer coming back). Your doctors may recommend one course of action over another because it will lower your risk of recurrence. Understanding what that actually means to your future will help you to be an active participant in choosing the best treatment plan for you.

How much does your risk of recurrence change?

If you hear that a certain treatment can reduce your risk by 25%, what does that mean?

To understand what the numbers mean about YOUR risk for a breast cancer recurrence, the key terms to know are Relative Risk and Absolute Risk.

Relative Risk is the number that tells you how much something you do, like taking a pill, can change your risk, compared to your risk without taking a pill.

Absolute Risk is the number of percentage points by which your own risk changes if you do something, like taking a pill. The size of your absolute risk depends on what your risk is to begin with.

Example of treatment reducing risk of recurrence

Suppose your risk of breast cancer is 12%, and then you decide to take Drug A, which can lower the risk of breast cancer by 25%.

That means your risk of breast cancer with Drug A could be 25% lower than without Drug A. That's the Relative Risk decrease with Drug A.

But how big a difference does a 25% decrease really mean for you? Lowering your 12% risk by 25% drops your risk by 3%.

That 3% is the Absolute Risk decrease for YOU, leaving you with a risk of 9%, if you take Drug A.