When cancer grows outside the prostate?

My uncle had his prostate removed due to cancer (last summer.) He recently went for a follow up and found out his PSA went from .04 to .07, they want him to be checked again in 3 months and said he will most likely need chemo. I was curious where the cancer spread to as the Drs did not say, other than it is "outside" the prostate since the prostate was removed. Sorry if I am not phrasing this question the right way. I'm not familiar with any of this. Thanks for any info - family is just trying to prepare for what to expect. Thanks!