Joe Biden's battle with cancer has "slowed" him down but his doctors are "encouraged" by how he has responded to treatment.

The former US President, 83, underwent radiation therapy after he was diagnosed with an aggressive form of prostate cancer last year and he's now opened up about his progress admitting "some days after better than others" but he's been forced to limit his promotional events for his new memoir Promise Me, America, which is due for release this month.

In a statement posted on Instagram, Biden explained: "My Presidential memoir, Promise Me, America, is coming out on November 17th.

"I hope you'll read it. It covers my years as President. The challenges we faced, the decisions I made, and why I made them. It's about who we are as a nation. What we stand for. And America's role in the world ...

"While writing the book, I was diagnosed with cancer, a disease known all too well to millions of Americans and their families.

"My doctors continue to be encouraged by how I've responded to treatment. And the prayers and kind words and well wishes from so many of you have meant more to me and [wife] Jill and our family than you can ever know."

Biden went on to reveal he's going to be scaling down plans to promote the book, adding: "Some days are better than others. It hasn't stopped me.

"But sometimes it slows me down. What that means is, unfortunately, I won't be able to do as many conversations about my book as I'd hoped. However, I'm hopeful the words on the page speak for themselves.

"Looking forward, I'm going to keep following what my father told me a long time ago: 'Champ, when you get knocked down, get up'. It's a good lesson for me. And America."

He concluded by writing: "We are blessed. America is the most unique nation on earth. Unlike other countries, we're built on an idea. An idea bigger than any ocean.

"More powerful than any army. Stronger than any tyrant or dictator. That idea? All of us are created equal. Promise Me, America, we'll never forget it."

Biden went public with his cancer battle in May 2025 and later confirmed the cancer had spread to his bones. He was undergoing radiation therapy and hormone treatment "as part of a treatment plan".