A small study from one hospital in Norway has suggested that PSA doubling times after surgery may predict the value of salvage radiation therapy alone as a second line form of therapy.
Servoll et al carried out a small retrospective analysis of data derived from 76 men treated by salvage external beam radiation therapy (EBRT) at a single Norwegian hospital between 1987 and 2010. All of the men in the subject pool had a biochemical recurrence after a failed radical prostatectomy prior to receiving the radiotherapy.
None of these men received adjuvant or neoadjuvant androgen deprivation therapy (ADT) in conjunction with the salvage radiation.
This study indicates the already accepted concept that beyond a PSA doubling time of 6 months or less salvage radiation therapy with EBRT by its self will not create a truly durable response in most men with biochemical recurrence after a radical prostatectomy.
Men with a PSA doubling time equal to or less than 6 months should not consider having just EBRT without ADT. Those men with PSA doubling times greater than 6 can discuss with their doctors the possibility of having EBRT without ADT.
The study also showed the same to be true if the post-surgical recurrence is associated with the presence of seminal vesicle invasion at the time of surgery.
However, remember this was a small study that was solely based on data from a single institution over a long time period. We need some confirmatory data generated by a much larger, multi-institutional clinical trial.