The 59-year-old, who famously led his Senegal side to victory over France in the opening game of the 2002 World Cup, was told he was in a terminal phase of cancer of the liver, lungs and colon 10 years later in October 2012.
Metsu admits it was a horrible shock to him and his family, but the Monaco defender's battle against the illness whilst at Barcelona has given him hope.
"I saw a programme on Eric Abidal that gives strength and inspiration to others. That is a powerful thing," he told L'Equipe.
"They gave me three months. It was an enormous shock. I was with Viviane, my wife, and we were crying as we left the hospital. You think about your kids and everyone around you.
"I started chemotherapy almost immediately and when I went to the hospital I was in a wheelchair, I was so weak but there was no question of giving up.
"Often as a coach, you tell your players, 'today is the match of your life'. But no, it isn't. Today, yes, I am playing the match of my life."
Although Metsu's health is still not good, he has gained 2kg recently having lost 17kg since being diagnosed, but says he has not allowed the illness to defeat him.
"When someone gives you three months, you fight to go further," he continued.
"In February, we didn't notice that I had pneumonia and I had chemotherapy on top of it. I stayed 10 days between life and death. That was the most difficult fight that I have known. Ninety per cent of people don't survive this situation but I had an incredible desire to survive.
"I have learned a lot about myself and family values. Today I can watch my children grow up and I have had nine months of happiness at their side and it's so much better than football.
"These kind of challenges can also bring a lot too. You see things differently. You take on a completely new way of thinking and how to be strong, like Abidal."
As well as his spell in charge of Senegal, Metsu has also coached Qatar, United Arab Emirates and Guinea, in a coaching career which began in 1987.