As noted in the quote, it is common to offer ADT, to patients who experience a rise in PSA after radiotherapy. The authors conduct a literature reviews and see benefit in patients starting intermittent ADT when there is a rise in PSA after a radical prostatectomy as well.
Cattarino S, Salciccia S, Gentilucci A, Innocenzi M, Gentile V, & Sciarra A. (2016) Intermittent androgen deprivation in prostate cancer cases with biochemical progression after radical prostatectomy: Are we ready to treat? Crit Rev Oncol Hematol [Epub ahead of print] 15 January 2016. www.ncbi.nlm.nih.gov/pubmed/26818049