White House chief of staff Susie Wiles has been diagnosed with early stage breast cancer but will continue working during her treatment, President Donald Trump said in a social media post on Monday.

Trump said Wiles’ prognosis is “excellent” and described her as “one of the strongest people I know.” He said Wiles plans to begin treatment immediately but made no suggestion she was pulling back on her work as one of his closest advisers.

“During the treatment period, she will be spending virtually full time at the White House, which makes me, as President, very happy!” Trump said on his Truth Social platform. “She will soon be better than ever!”

It comes as the Republican president confronts mounting challenges on global and national fronts, from the war in Iran and soaring oil prices to this fall’s midterm elections and Americans’ concerns over affordability.

Wiles, 68, is a longtime Trump ally who rose from his campaign co-chair to his closest adviser and counsel. The first woman to become White House chief of staff, Wiles spent decades as a lobbyist and political operative in Florida and led Trump’s 2016 effort in the state.

She mostly shuns the spotlight but drew attention in December with an unusually candid Vanity Fair interview in which she made critical remarks about Trump administration leaders including Vice President JD Vance and Attorney General Pam Bondi. Trump underscored his trust in Wiles in the aftermath, calling the interview a “hit piece” and describing Wiles as “fantastic.”

In his Monday post, Trump reiterated that Wiles is “tough and deeply committed to serving the American People.”

“Melania and I are with her in every way, and we look forward to working with Susie on the many big and wonderful things that are happening for the benefit of our Country,” Trump said, referring to first lady Melania Trump.