Milne, 71, was on Newstalk ZB this morning with Jack Tame and said he learnt of the news on Wednesday.
Milne went to a urology specialist to hear the results of his prostate biopsy that day.
A prostate biopsy can identify if there is cancer in a prostate and if so how much is present.
Milne's MIR scan had show there was most likely cancer in his prostate. On a one to five scale to measure how likely it was, Milne was a four.
However, when measured on the Gleason score which measures the seriousness of the condition, Milne was a one.
"If you're one, you're damn lucky; if you're a five, you're in trouble. Jack, I got one.
"A tiny amount of cancer, but contained and slow moving, no further treatment required."
Although both Milne and his wife Linda were relieved with the result, he said "we didn't celebrate, it didn't sound right" as the pair have several close friends fighting their own cancer battles.
Milne said he is thankful for the experience.
"When facing even only the slightest prospect of death, if you survive it, it's a gift."
"There's nothing like waiting for your Gleason score to sharpen your focus on what you might be taking for granted."
Newstalk ZB and Gold host Andrew Dickens revealed last year that he was also diagnosed with prostate cancer.
He spoke about his journey last October, announcing he was having an operation to have his prostate removed the following month.
"Oh, it was very easy actually," he says without missing a beat. He explains he felt he could do more good sharing his story than not, mentioning he argued his way to be properly tested. He says he is "fixed" now, joking he doesn't have to wear nappies.
"So it saved my life, so why wouldn't I, in the public eye, come out and use that, and say 'just get yourself tested'?
"You've got to be honest and real in radio and in public life, and if you aren't, then how can you expect people to be honest and real back?"
