My uncle has a spot on his back it is pretty big and black scabed and has just recently gotten larger with a nasty crater looking thing in it he has had it for ten years and its gotten bigger what are the chances that it spread to other areas of his body?

Needs examination: Sounds like this lesion needs to be looked at soon by his primary care physician.

Depends!: It's hard to say if this can spread. But if it is a type of skin cancer it could. Tell him to get checked out. A biopsy is easy and painless and, if it is shown to be a type of cancer, the proper treatment can be done to prevent or delay further spread. Any longstanding skin abnormality can become cancerous at any time. If it changes in appearance, see doc!