ADT Monotherapy for mHSPC: How to Identify the Right Patients

Announcer:
Welcome to On the Frontlines of Prostate Cancer on ReachMD. On this episode, we’ll learn about the use of monotherapy to treat metastatic hormone-sensitive prostate cancer, or mHSPC, for short, with Dr. Daniel George. Not only is he the Eleanor Easley Distinguished Professor of Medicine, Surgery, and Urology at Duke University, but he’s also an American Cancer Society Impact Research Professor and practicing GU oncologist at Duke Cancer Institute. Here's Dr. George now.

Dr. George:
Approximately 36 percent of patients in this last year—in 2023—were still being treated with ADT alone. That’s a big improvement from 74 percent in 2017, but it’s still not where we want to be. It’s hard to say exactly where this number should be, but I actually look to another database—our IRONMAN database—for some guidance. This is an international database that’s now based in up to 16 countries for patients with metastatic hormone-sensitive prostate cancer or castrate-resistant disease. And if we focus on the metastatic hormone-sensitive population from 2017 on, we have hovered between 78 and 84 percent of patients getting combination therapy, either ADT and docetaxel, ADT and an ARPi, or the triplet. But roughly 20 percent of patients are still in that population being treated with ADT alone.

Now, these are all prostate cancer specialty centers—largely medical oncology groups—and are very consistent, interestingly, across the countries, so it suggests to me that probably 20 percent is the right number that should get ADT alone. And you might say, “Well, where’s the level 1 evidence for ADT alone?” And there isn’t one. But what I’ll tell you is that not all metastatic patients are the same; some of them can have a slow natural history to metastasis, some of them can have a real low volume, some can have a very slow PSA doubling time, all of which are very prognostic, and some patients can respond really well completely to ADT alone. We saw in our IRONMAN registry that about 30 percent of patients get a PSA undetectable on ADT alone, and those patients do very well. So I’m not convinced that nobody should get ADT alone, but it’s a selective group, and it’s probably no more than 20 percent of patients. So there’s still probably some education to do out there, but the number isn’t zero. There is some, and we probably just need more prospective data to help guide us in exactly who those patients should be. 

Announcer:
That was Dr. Daniel George talking about the use of monotherapy to treat mHSPC. To access this and other episodes in our series, visit On the Frontlines of Prostate Cancer on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!