Sarra praised her husband for carrying on with his presenting duties for the BBC at the World Track Cycling Championships in Copenhagen at the weekend after his diagnosis became public.
She added: “Watching him on the BBC at the weekend was like watching a masterclass in strength of character, dignity and humility.
“I’ve said it before and I’ll say it again – he truly is my real life superhero.”
The couple are currently on a family holiday with their two children Callum and Chloe, who are aged 10 and seven.
Sir Chris told the Sunday Times that he had been diagnosed with primary cancer in his prostate, which had spread to his bones – meaning it was stage four.
The Edinburgh-born athlete revealed earlier this year that he had been diagnosed, but he had not previously disclosed the type of cancer.
Just before Sir Chris’s tumour was discovered, Sarra had undergone scans that would later show she had multiple sclerosis, a degenerative disease.
Sir Chris, who was first inspired to take up cycling by the famous BMX scenes in the film E.T., had won six Olympic, 11 world and 43 World Cup titles by the time he retired.
The cyclist first won gold at the Athens Olympics in 2004, and went on to secure three more gold medals four years later at Beijing. He won two further golds at London 2012, before retiring from cycling in 2013.
His haul of six Olympic golds is the second highest total by any British Olympian behind Sir Jason Kenny’s tally of seven.