Former United States President Joe Biden has said that his cancer battle could limit his participation in activities for his presidential memoir, ‘Promise Me, America’.

“While writing the book, I was diagnosed with cancer, a disease known all too well to millions of Americans and their families,” Mr Biden said on Sunday.

Mr Biden, 83, said in a post on X that his doctors are hopeful about his progress with treatment. He admitted that some days are harder than others.

“My doctors continue to be encouraged by how I’ve responded to treatment,” he said, also noting well wishes from Americans.

The former president said that although the illness has not stopped him from doing his activities, it sometimes slows him down, making it hard for him to talk about the book as much as he planned.

“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,” he said.

The memoir, set to be released on November 17, explores his time in the White House, the problems his government faced, the choices he made and why he made them.

He added that the book also explores “what we stand for. And America’s role in the world. More than anything, it’s about my faith in the American people and the great American experiment in self-governance and democracy.”

Mr Biden, America’s 46th president, announced in May 2025, months after he left the White House, that he had been diagnosed with prostate cancer and said that “By the time we found it, it had already spread to my bones.”