Well, there is no mention in any fluff about any orc who has lived very long. Sure most orcs would die in battle sooner or later, but there has to be at least some undefeated super-boss somewhere who has had no reason to die in battle, and thus lived for 100+ or something years.
However, the apparent lack of evidence doesn't mean there is none. If you ask me, any answer is as good as any other, since there is no official fluff on this one.