Former US President Joe Biden has said his cancer will limit the number of public appearances he can make to promote his upcoming presidential memoir, telling supporters that treatment has slowed him down at times.

Biden, 83, announced the news on Sunday in a post on social media, just over a week before the book, titled Promise Me, America, is due to be published on 17 November.

“Some days are better than others. It hasn’t stopped me. But sometimes it slows me down,” he wrote. “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.”

A memoir written through illness

Biden said he was diagnosed with cancer while he was writing the memoir, which looks back on his four years in the White House. “It covers my years as President. The challenges we faced, the decisions I made, and why I made them,” he wrote. “It’s about who we are as a nation. What we stand for. And America’s role in the world.”

He added that his doctors “continue to be encouraged” by how he has responded to treatment, and repeated a line from his father: “Champ, when you get knocked down, get up.”

Biden revealed his diagnosis in May 2025, less than four months after leaving the White House. His office said at the time that he had a more aggressive form of prostate cancer that had spread to his bones, but that it appeared to be hormone-sensitive, which allows for effective management.

His son Hunter told the BBC in August that the cancer had spread further into his father’s bones, describing the condition as very painful and debilitating. Biden completed treatment for stage four cancer in October 2025, and said last month that the radiation treatment he received last autumn had worked as intended.

A message on early detection

Last month, during Prostate Awareness Month, Biden shared a personal message urging men to see their doctors for early detection. “By the time we found it, it had already spread to my bones,” he wrote. “When prostate cancer is caught early, the five-year survival is close to 100%.”

Biden, who turns 84 on 20 November, is the oldest living president. His memoir arrives months after former first lady Jill Biden released her own book, A View from the East Wing, in June.

Despite the scaled-back promotion plans, Biden struck an upbeat note about the book itself, saying he hoped readers would find in it his faith in the American people and in what he called the great American experiment in self-governance and democracy.