Radio host Kate Langbroek has revealed her toughest moment as a parent – the day she realised she might lose her son, Lewis, to leukaemia in 2010.

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In her weekly column for News.com.au, Langbroek bravely revisits “one of the longest, hardest days of my life”.

“It was the day my boy, my firstborn, my heartsong, my love bug, my beloved, my honey, my bunny, my boo was wheeled into surgery to have a biopsy performed on his optic nerve.

“He was being treated for leukaemia, and that was already beyond awful. But the week before, he had gone blind in one eye — a fresh terror.

“Our oncology team at the Children’s Hospital feared he had relapsed, that the leukaemia was overcoming the treatment. That we were losing. It was a dreadful day.”

While her son thankfully entered remission and is now a healthy 11-year-old, the 49-year-old remembers his surgery as “the day I wished I was never a mother. Because I could not bear it”.

“I could not panic and I could not run. Because I was his mother. And because he was frightened, I could not be.”

Four years later, Langbroek is preparing to send Lewis off on an school trip to Italy.

“I am a boy’s mother, and doing that job well means knowing how to let go,” Langbroek says of her decision to allow her eldest to travel despite his past illness.

“I did not know that when I took on the role. I had not thought it through. But now it is upon me, I am performing to the best of my limited, but infinite, abilities.”

Langbroek currently co-hosts the Hughesy & Kate show on KIIS with Dave Hughes.

She has four children with her husband Peter Allan Lewis.