Please help. White thing in anus. It hurts so and burns and itches. Could it be colon cancer? What do you think it is?

Need physcial exam. If you're having this much pain and discomfort, you really need this examined in person. From your description, this is most likely an anal condyloma (genital wart). And given your age, it is very unlikely that this is malignant. But without seeing the lesion to know size, shape, color, location, etc., we can't give you a definitive answer.