Conservative MP Nick, who beat the disease nine years ago, said doctors at King’s College Hospital accident and emergency department had found a cancerous tumour in his head.
He joked that people “might think that explains a lot about my recent behaviour” and said he was undergoing tests at the London hospital.
Mr Boles tweeted: “Some news: doctors have found a cancerous tumour in my head. Some of you might think that explains a lot about my recent behaviour.
“At @KingsCollegeNHS doing tests and expect to start treatment soon. I fought cancer off 9 years ago and I am sure I can do it again.”
Referencing a parody account popular with Westminster insiders, he added: “Giving up Twitter until I have got this thing licked. But @GeneralBoles will keep you entertained. Wish me luck!”
Mr Boles managed Michael Gove’s failed Tory leadership bid after the EU referendum and was forced to apologise after it emerged he had encouraged tactical voting because he was “seriously frightened” about Andrea Leadsom getting on to the ballot.
The former skills minister quit the Government when Theresa May won the contest and took over as Prime Minister.
A close ally of David Cameron, he was part of the informal “Notting Hill set” of modernising Tories and his work with the Policy Exchange think-tank before becoming an MP in 2010 helped frame the former PM’s agenda as leader.
Today (Wednesday, October 26), Labour leader Jeremy Corbyn and Prime Minister Theresa May paid tribute to Mr Boles at Prime Minister’s Questions in the House of Commons.
Mr Corbyn said: “I just want to pay tribute to Mr Boles for the social media message he sent out this morning.
“It shows amazing humour and bravery and we wish him all the very best and hope he fully recovers from this.”
Mrs May replied: “Can I also join you in commending my honourable friend for being willing to be so open about the health problem that he has, and we wish him all the very best for the future and for his place here in this House.”