But there is a statistically significant advantage to this procedure in bitches which are not part of a breeding program. It is no longer medically justifiable to castrate dogs for prevention of cancer. The overwhelming mass of data to the contrary can no longer be ignored, and publications are out there so that no veterinarian can use the excuse of ignorance. Castration predisposes to highly malignant prostatic cancer. Nearly all dogs afflicted with this nasty tumor are neutered individuals.
Testicular cancers are very rare and almost always benign.
Perianal adenoma can be treated by castration if and when it arises. It too is benign although messy. Many owners wish to castrate their male puppies thinking that all sorts of behavioral problems will be solved. Such as roaming. Most of these behaviors can only be altered by husbandry and training.