See, that does make sense. However, there's been at least one case in comics before Secret Invasion (In his own title) where his healing factor was turned to the max, outpacing the cancer and making him look completely normal. That seems to contradict the Secret Invasion story.
Of course, I shouldn't exactly expect constant consistency from comics that are not written by the same authors, but... Well, his healing factor knew well enough what his body was supposed to be like for that entire arc.