A puppy who just turned 4 months old, who had 2 palpable testicles at 8 weeks (based on my check and an exam by our vet), has been to the vet twice with their new owners now and both times their vet could only palpate one testicle. They are pressuring the owner to neuter him asap because of the risk of cancer to the retained testicle, and have presented some pretty scary stories to push their cause.
I know that retained testicles are at risk of becoming cancerous, but I normally recommend that families wait at least 14 months to neuter to give the puppy a chance to finish growing. Obviously these owners do not want to put their puppy at risk of cancer (especially the nasty spreading kind that their vet is worried about) but also don't want to neuter him this young if they don't have to based on the studies I have sent them which show an increased risk of cancers later on/cruciate injuries, etc. Personally, if it was my puppy I would not be panicking yet but it is not my puppy so I am looking for unbiased advice/excperience.
My questions are:
how long would you wait before neutering this type of puppy?
What is the earliest one would worry about cancer in a retained testicle, and what is the latest it could drop if it was going to?
Thanks in advance.