The author and polemicist Christopher Hitchens yesterday announced he was cutting short a promotional book tour in order to undergo chemotherapy treatment.

There were reports that the the British-born writer, who was a heavy smoker until giving up several years ago, had been diagnosed with cancer.

In a statement issued by his US publisher, Twelve, the 61-year-old said: "I have been advised by my physician that I must undergo a course of chemotherapy on my oesophagus. This advice seems persuasive to me. I regret having had to cancel so many engagements at such short notice."

The firm gave no further details other than asking for his privacy to be respected. Hitchens launched a high profile book tour last month to promote his memoir Hitch-22, which tackles subjects ranging from the Middle East and Zimbabwe to his friendships with prominent writers including Salman Rushdie and Martin Amis. The volume has already entered the bestseller lists.

Hitchens has in the past described himself as "an essayist and a contrarian". As a journalist, critic and war correspondent, he has carved out a reputation for barbed repartee, scathing critiques of public figures and a fierce intelligence.

In his 2008 book "God Is Not Great", Hitchens put himself on a collision course with major religions through his advocacy of atheism.

He lives in Washington DC and became an American citizen in 2007, although also retains British citizenship. Hitchens appeared at the Guardian Hay Festival this summer.