Intermittent ADT ?

ADT is doing you the most good while cancer is still dying from the radiation treatment. You can imagine that last cancer cell clinging to life desperately searching for a scrap of testosterone to survive on and then you give it that little bit of testosterone at 6 months and it manages to survive. So no, quitting at 6 months would be too risky. But an argument could be made that maybe at one year all the cancer has died and restoration of testosterone would not hurt anything. No one really knows what would happen for any particular case. Even if you go the full recommended 18 months, there are similar cases like yours in the past where even 18 months was not sufficient. So you and your doctors just go with what statistically looks prudent and hope for the best. If you stop ADT too early and your cancer manages to come back, you are now fighting a different battle and wide area radiation is no longer available to you. Only spot radiation from SBRT remains available. So think long and hard about quitting ADT early.

I know a lot of people who have gone on vacations from ADT. They normally do that after having undetectable PSA’s for at least a year. The people that I know that have done this have usually had to come back to ADT because not only did their PSA rise, but they had metastasis show up. Each time they have gone on vacation it has come back quicker. ADT isn’t the only drug to use, The ARPI drugs (Zytiga, Nubeqa, Xtandi and Erleada) Can replace ADT and all but Zytiga Does not reduce the testosterone, but can suppress prostate cancer from Using testosterone.

Those that had metastasis show up had it zapped with SBRT radiation.

The PSA nadir for radiation without ADT typically takes more than 6 months and can be up to 18 months. With ADT your PSA should be easily under 0.1 but that is the ADT more than the radiation suppressing it. If you stop ADT at 6 months post radiation your PSA will bounce back up but should still be below 1 due to the radiation. It should then decline if you do not have a relapse. Discuss this with your doctor about a shorter course of ADT. Risk is much less to shorten to 12 months vs. 6. As noted, you have had your lifetime dose of radiation to the prostate so there will another long course of treatments.

Hi. My husband has been on ADT and ARPI since Sept. (6 months) More details are in my profile. Long story short, his oncologist is suggesting intermittent ADT may be the next step, after checking the PSA again at 9 months. He said he is considering that treatment based on the results of the EMBARK trial.

@stephenz, I did intermittent ADT for my Gleason 9 prostate cancer at age 71. So far, VERY pleased with the results.

Although your radiation treatment was different than mine (I had HDR Brachytherapy and 5 sessions SBRT), I'm guessing we should have similar results:
-- After 1 month on ADT (Orgovyx), my PSA dropped from 31 to 4.3 ng/ml. Then I did radiation treatments.
-- 3 months later, my PSA dropped to 0.03
-- 3 months later, my PSA dropped to 0.02
-- 3 months later, my PSA was undetectable (< 0.01)

My Medical Oncologist had recommended 18 months ADT (Orgovyx). But I worried about the long-term negative impact on my cardiovascular disease. And the other side effects were bad.

So, after 11 months of continuous ADT, I decided to take a "holiday".

2 months later, my PSA went from undetectable to 0.26. Then I went back on ADT.

2 months after re-starting ADT, my PSA was again undetectable. My medical oncologist concluded there was no evidence of disease. So I again stopped ADT.

One year later, today my PSA is 0.22. VERY pleased!

I continue PSA testing every 3 months. If/when my PSA rises to 1.0, I'll get a PSMA PET scan and see if there's a reoccurrence that needs treatment. Hopefully that's years down the line.

Best wishes.

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