I tried Google just now and found this:
So it seems there may an association between vasectomy and PCa, but by no means proven.
The way you worded the original question (and thread title) implied that you were interested only in those of us who have had vasectomies. So the non-vasectomies would have stayed away. As a result, your survey will be skewed towards vasectomies.
So you non-vasectomy guys, get in here and even things up!