Neoadjuvant ADT - is a slowing PSA drop rate normal?

[sixmongoos]

Hi all, first time poster here.

My father (61, very healthy) was DX'd Sept 2021 with high-risk locally advanced prostate cancer with the following profile: G9, pre-op PSA ~58, MRI showing 1 possible pelvic LN mets. He had no symptoms and it came out of nowhere during his check up. From the treatment options, dad wanted to treat it aggressively given his relatively young age, so he opted for RALP + PLND (with high likelihood of ADT + RT afterwards) with one of the top urologists in his home country (South Korea). Given the large tumour size, doctor wanted him to be on neoadjuvant ADT (Zoladex injection every 3 months + daily casobit. He's been on it for 6 months now, with minimal side effects (just mild hot flashes occasionally).

During his 3-month check up in Jan 2021, his PSA dropped massively from 54 to 3 but the doctor wanted to wait another 3 months. Yesterday, he had his 6-month check up, and I was surprised to find out that it only dropped from 3 to 2 as I was expecting something a lot lower.

Is this slower PSA decline normal, or has anyone seen similar trends before? I understand PSA velocity is very person-dependent but I'm worried if the relatively small drop indicates that the ADT is slowing becoming ineffective only after 6 months. We will find out more during next week's meeting with the urologist, but wanted to be ready if bad news is to come.

The below is his PSA summary:

- July 2021: PSA 58 (DX'ed)

- Oct 2021: PSA 54 (started neoadjuvant ADT)

- Jan 2022: PSA 3 (3-months post-ADT)

- April 2022: PSA 2 (6-months post-ADT)

[Magnus1964]

It sounds like he is responding well to treatment.

[TylexGP]

Hi Your father and I have some similarities in our PCA. I am a little younger DX at 56 with no symptoms other then an increased PSA. Below is my journey so far. Currently my PSA is stable between 0.16 to 0.11.

On 3/31/2021, I was diagnosed with G9 T3bN1M0 prostate cancer with intraductal histology and a BRCA2 mutation. On 5/4/2021 I started treatment with ADT and abiraterone. My PSAs for the year (monthly due to the aggresiveness of my PCA)

5/4 PSA 10.48 (ADT + Abi Started)

6/7 PSA 0.7

7/12 PSA 0.35

7/26 HDR Brachytherapy

8/11 PSA 0.45

9/9 PSA 0.2 EBRT 25 txs in September 2021

10/13 PSA 0.17

11/9 PSA 0.13

12/14 PSA 0.11

2022

1/12 PSA 0.16

2/12 PSA 0.13 (CT Scan no findings other than suspect Rt External Iliac node is no longer visualized/NaF PET bone scan detected no bone Mets)

3/12 PSA 0.11

4/13 PSA 0.13

So at aprox. one year after starting treatment the best I can tell is I have stable disease with a PSA fluctuating from 0.11-0.16

I wish your dad well in his treatments.

[Tall_Allen]

We call that "persistent" PSA. With lymph node metastasis, he should have had immediate RT+ADT. I don't understand what he is waiting for. The urologist's job is done, he should be discussing next steps with a radiation oncologist.

[Tony666]

I was in a similar situation. Age 60, Gleason 9 Though psa was lower than your fathers at 9. I also decided to do 6 months neoadjuvant adt followed by prostatectomy. The main difference is that my protocol at NIH called for more “intensive” adt - adt + enzelutimide + abiraterone + prednisone. My psa did fall to undetectable (<.03) by 6 months. I think this is true for most patients on this protocol. I am v happy with the outcome - after 2 years no detectable cancer.

However, this protocol is still experimental and not standard of care. Also, your father did a less intensive adt regime and the trial results of less intensive neoadjuvant adt before surgery don’t show much benefit. My guess is that if your father’s psa is still 2 at 6 months, this indicates that your worry that the neoadjuvant adt didn’t work that well is justified. Rather than proceed with the surgery which would likely need to be followed by radiation, you may want to consider going directly to radiation plus seeds. I know it’s hard to switch course midstream, but it’s important to listen to what the data is telling you.

[j-o-h-n]

Listen to Tall_Allen,

Good Luck, Good Health and Good Humor.

j-o-h-n Wednesday 04/20/2022 11:29 PM EST

[sixmongoos]

Appreciate the inputs everyone. Regarding treatment plan going forward, I think we will find out more during next week's meeting. The hospital's urology and oncology teams have been already working together (medical system's a bit different here from what I'm aware), so we plan on leaving it in their hands on what the best course of action will be for dad. Will provide an update when we find out more.