This study is recent. I think there is definitely a link to prostate not receiving sperm that leads to prostate cancer in some men. There was another study that someone quoted here that points to vasectomy leading to 20% increased risk in terminal prostate cancer. Feel free topmost it here.
I posted something similar the other day, the link keeps being disputed on vasectomy and prostate cancer, but the infertility prostate cancer link seems to again indicate that compounds produced by the testicles and reaching the prostate have a protective immune modulating effect.
Once that system is disrupted in some studies there is a statistically signicant change in the risk of prostate cancer.
The testicles are an immune privileged site and those compounds reaching the prostate are therefore likely to protect it somewhat also.
Male immune reproductive privilege and it’s disruption is quite an interesting area, similar to the female reproductive system, the eyes and the central nervous system that also have similar but somewhat differently produced immune privilege.
Though there have been a number or recent studies flagging the link, most vasectomy patient guidance still will state there is no elevated risk!