Sir Michael Parkinson was diagnosed with prostate cancer in May after a routine health check and doctors immediately began organising his treatment, which involves five sessions of radiotherapy a week.
The renowned journalist and interviewer said he was left in shock by the diagnosis, but said he was "in wonder" at the "marvelous" work of medical staff after initial thoughts of his own mortality.
The 78-year-old said: "I had to start calling a few of my social engagements to tell them I couldn't do it - what do you say to them?
"When you are told you have something like cancer, it is a shock. But the cancer specialist said: 'I will assure you, you will not die of this.'
"I am concerned about it, of course, but I am not frightened of it."