Yes, we will have to wait for the RADICALS trial to know that for sure. While there are no definitive answers, more than 12 months might be better than less than 12 months in risky cases of recurrence:
www.europeanurology.com/article/S0302-2838(15)00410-8/fulltext/duration-of-androgen-deprivation-therapy-influences-outcomes-for-patients-receiving-radiation-therapy-following-radical-prostatectomy