The hand satisfies the rules of 20 and 22, with very good intermediates, so I wouldn't pass. 1C is nearly 100% in my opinion. A good partner will not bid spades, so the concern over a rebid is (I'd estimate) going to occur less than half the time- lefty may be the spade overcaller. I wouldn't rebid 2C if partner responds 1S and opponents pass, but 1N isn't horrible. I might get reopen with a double over lefty's 1S and find partner with a spade stack.