And the diagnosis must have come as an added blow to someone whose voice is the key to their career.
It's being reported that doctors are using chemotherapy and radiation as alternative to surgery on his larynx because of the possible dangers to the actor's ability to speak.
Understandably, the Oscar-winning star has also had to scale back commitments to promote Wall Street: Money Never Sleeps, the sequel to his cult movie about financial greed and his biggest project in years, because of the treatment.
Whatever the challenges, the supercouple are determined to face them with a united front.
Michael himself has said that he is "optimistic". Meanwhile the Daily Mail reports that the Welsh actress is "100 per cent" behind her husband.
In April she gave him her full support when his son Cameron was sentenced to five years for drug possession – relocating from their base in Bermuda partly so that he could attend the trial.
His spokesman has made it known that the Oscar-winning stars are no longer in America – making it possible they are on the island.
Until now the retreat has been their safe haven, a place where they could raise their children, Carys and Dylan, in relative privacy.
Being back home would give the 65-year-old a boost.
Also likely to help is the example of his own doughty father Kirk, now 93 years old and someone Michael describes as "pretty inspirational".
Kirk was robbed of the power to speak after a stroke in 1996 – but refused to give up.
His no-nonsense approach keeps his son from feeling sorry for himself – as was the case after the younger Douglas' knee replacement operation.
"After this fairly serious operation, I go and see him and he says: 'You know, when I had my double knee replacement I was 88!'"