Complicates as in ... ?
Also, statistical outlook data for cancers, surgeries, etc, are based on statistically average populations. Vegan people deviate that from that population, and that could mean their outlook/treatment be different.
Jobs' whipple surgery drastically changed his digestive system. And because it's at least sort of rareish, I am not sure any good data exists for proper procedure on vegans who have undergone a whipple surgery.
In the fourth paragraph: "Jobs is a pescetarian (not a vegetarian or vegan as is often claimed) — although he does not eat mammalian meat, he reportedly eats fish from time to time."