A cancer update from former President Jimmy Carter.

FOX's Jon Decker reports from the White House:

Although he says his body is responding well to treatments, former President Jimmy Carter says he's not entirely cancer-free.

In an interview with Entertainment Tonight, Carter said that sometimes the cancer spots return, including in his brain.

In December, Carter announced that his brain cancer was gone, and that an MRI showed no signs of cancer at all.

The 91-year-old former President said he'll continue with his treatments until his doctors tell him he no doesn't have to anymore.

At the White House, Jon Decker, FOX News.