You're asking a really good question, but there are no definitive answers. Here's a review of what we know about
how long to continue ADT for when having salvage RT:
/pcnrv.blogspot.com/2016/08/combining-androgen-deprivation-therapy.htmlBut that does NOT cover the situation where there are known positive nodes. I would think that with a positive node, adding ADT would be a reasonable precaution, but there is really no data to help guide that decision.