Sorry about your missing cat. Please don't worry too much - I know its hard not to, but I have 20 cats around the farm, and some of them, male and female, go off hunting in the fields. Sometimes they are gone over a week - obviously finding birds and rabbits etc. while out. I think they only return once they are hungry!!
Hopefully thats just what your cat has done. I am sure he knows where home is, and will return soon. One of my cats walked 8 miles back to our old house. It took him six weeks, but he was fine, and looked in good health. Cats are survivors, and will stop at other houses where cats live to get food.
I would keep checking with neighbours though, just to make sure he has not gone in garages, sheds etc......cats are so nosey, aren't they, that they do sometimes go in places they are not supposed to.