Dr. Sartor: The next abstract I'm going to cover was presented by Chris Parker at one of the presidential sessions at ESMO 2022. Chris Parker's at the Royal Marsden, done fabulous work in prostate cancer, and here he was going to be presenting the RADICALS-HD trial.
Basically, this looks at the duration of androgen deprivation therapy with postoperative radiotherapy. It's a randomized trial and that all of these individuals had previously failed radical prostatectomy and had no prior ADT.
It turns out that there are three arms and a little bit of an unusual randomization. The randomization was between no ADT, so just radiation alone, radiation plus six months of ADT, or radiation plus 24 months of ADT. And investigators were encouraged to do what's called a three-way randomization. And by three-way randomization, that meant between zero, six months, and 24 months. However, you could also randomize the patients between none versus six months or the six months and 24 months. So, there was a variety of ways to look at this, but in the bottom line, it's zero, six, or 24 months, and this is for hormonal therapy in combination with radiation post radical prostatectomy.
First of all, the important thing in my mind is there was no overall survival benefit in any of the arms. So, no one lived longer, or no arm lived longer as a consequence of receiving zero, six, or 24 months of the hormonal therapy combination with radiation. Now, they looked at rPFS as the primary endpoint, radiographic progression-free survival. They did find that there was no difference in rPFS for zero versus six months, but they did find that six months versus 24 months led to an improvement in rPFS for the 24 months.
In my opinion, however, there was not a lot of difference. And at 10 years, if you use six months, it was 72% in terms of the radiograph progression-free survival versus 78. So, 72 versus 78 for the [inaudible 00:08:49] hormones. So, yes, you do gain six percentage points at 10 years. And yes, there was a hazard ratio that was statistically significant at 0.77. But I'm not sure that giving two years of ADT really adds huge value over the six months. Now, there was an interesting thing that was noted, and that was when they actually did a separate analysis between zero and 24 months in terms of the metastasis for a radiographic progression-free survival, there really wasn't much difference.
So, my conclusion, maybe not everyone else's, but my conclusion is that you don't have a lot of added value by going to 24 months as compared to six months, and maybe there's not much value of going between zero and 24 months. We know from other studies that the time to PSA progression is improved with short-term ADT. I'll talk about RTOG 0521, recently published in Lancet, 2022 Lancet Publication. But I think it's not really necessary to go two years of ADT in combination with radiation post radical prostatectomy, in my opinion. So that's the update from RADICALS-HD presented by Chris Parker at ESMO 2022, but, quite frankly, with my own interpretation interspersed, which I've stated in the last few minutes.