A retrospective cohort study published in Feb 1 2014 of Journal of the American Veterinary Association.
The link provided is an article by Dr Becker, who with-in the article provides the link to the actual study.
In line with the GR and Rottweiler studies, more confirmation of the health risks to spayed/neutered animals.
I leave it to the readers to look up the study.
Will Spaying/Neutering Increase Your Dog's Risk of Cancer?