Over 30% is an... interesting figure. Information is absolutely all over the place and seemingly no one can agree on even a similar ballpark. Some studies say 30% with a 9% MOE, others say 26.8% after 10 years at worst and substantially less overall, a Danish study even went all the way up to 56% after 10 years. In his age bracket, depending on a slew of factors including his previous lifestyle up until then (smoking is a well-known risk multiplier, for example) and how well the aftermath is handled, the risk is actually probably closer to >40% after 10 years. Sorry Kaoru.
Still, chin up! This coin toss is rigged in your favor, and 10 years is more than most!