My oncologists (medical and radiation) had been pushing me to have a PSMA scan for two years. Even though in 2023 my PSA rose from .67 to 1.37, I pointed out that a PSMA scan would not change my treatment. We ran another Axumin PET in January, which was stable, if not better, than the one in September 2021. Finally, though, after PSA rose to 1.92 in June, we scheduled one for July 17.
The PSMA on 7/17 showed no abnormal uptake outside of the prostate. Nothing on bones, organs, lymph nodes, seminal vessels, etc. This contradicted 6 years of MRIs, CTs, nuclear bone scans, other types of PET scans. Uptake inside the prostate, however, was 24.7.
My MO said it was a good outcome, but that's all he said, although he seemed surprised.
I met with my RO on Wednesday. Very nice doctor, but he's never done any treatment on me, we've just discussed scan results. He's never pushed anything.
However, at this meeting, he thought I now qualified for radiation to the prostate and pelvic bed. I was diagnosed in 2018 with multiple distant bone Mets and determined not to qualify for radiation. He wanted to discuss with my MO and also with my new urologist who is getting me the Provenge immunotherapy that I recently posted about.
Has anyone had such a turn of events after having a PSMA scan?
I'm trying not to get overly excited about this until it plays out more, but it sure sounded good hearing it.
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I've been on Lupron and denosumab since Fall 2018. That's been my only treatment.
I don't know what's up with the bone mets. They all showed small SUV on Axumin scan in January (4.3-4.8 range). Were they cancer at all? I don't know the answer.
PSA could be rising due to new activity within the prostate--I don't know.
I suppose what I was really asking was has anyone gotten a much better result from a PSMA scan than from earlier, less sensitive scans? I expected the PSMA to show more spots, more locations, higher uptake. That's the manner in which it's generally discussed in PCA forums the last four years or so. But I haven't leaped to any conclusions.
I am de novo polimetastatic with distant Mets but my Mets are not visible now on the scans. Prostate has a high DHT natural environment therefore the crpc is growing.
Yes, after radiation, the proportions of PSA production and PSMA avidity can indeed shift compared to their levels before or immediately after treatment. Here’s how these shifts might occur:
### 1. **Impact of Radiation on PSA Production**
- **Initial Reduction in PSA:** After SBRT, you likely observed an initial drop in PSA levels due to the widespread damage or destruction of cancer cells. However, the remaining radiation-resistant cells could still produce some PSA, albeit at lower levels initially.
- **Possible PSA Increase Over Time:** If these surviving cells start to proliferate or regain some function, PSA production might gradually increase. However, the rate and extent of this increase would depend on the extent of damage these cells sustained during radiation.
### 2. **Impact of Radiation on PSMA Avidity**
- **PSMA Expression Post-Radiation:** PSMA expression in cancer cells can persist even after they are damaged by radiation. Initially, if radiation effectively reduces tumor burden, PSMA avidity on a PET scan may decrease. However, any surviving cells could still express PSMA, leading to detectable avidity on follow-up scans.
- **Changes in PSMA Avidity:** If the surviving cells start to recover or mutate, they might either maintain, increase, or, less commonly, decrease their PSMA expression. These changes would directly influence PSMA avidity observed in subsequent scans.
### 3. **Shifting Proportions: PSA vs. PSMA Avidity**
- **Scenario 1: Increased PSA with Stable or Decreased PSMA Avidity**
- If surviving cells start producing more PSA but do not increase PSMA expression proportionally, you might observe a scenario where PSA levels rise, but PSMA PET scans show stable or reduced avidity. This could happen if the cells' ability to secrete PSA improves faster than their PSMA expression.
- **Scenario 2: Increased PSMA Avidity with Stable or Slowly Rising PSA**
- Conversely, if the surviving cells maintain or increase PSMA expression without a corresponding increase in PSA production, you might see a situation where PSMA PET scans reveal increased avidity without a significant rise in PSA. This could happen if the cancer cells adapt to maintain or enhance their surface markers like PSMA even while producing less PSA.
- **Scenario 3: Proportional Increase in Both PSA and PSMA Avidity**
- In some cases, both PSA production and PSMA avidity could increase proportionally if the surviving cancer cells proliferate and regain both their PSA production capacity and PSMA expression.
### 4. **Clinical Implications of Shifts**
- **Monitoring and Interpretation:** Shifts in the proportions of PSA levels versus PSMA avidity can provide important clues about the behavior of the remaining cancer cells. For example, a significant rise in PSA with minimal PSMA avidity might suggest that the cancer is becoming less reliant on PSMA pathways or that the cells are in a more dedifferentiated state.
- **Tailored Treatment:** Understanding these shifts can help your oncologist tailor follow-up treatments. For example, if PSA rises but PSMA avidity is low, systemic treatments targeting non-PSMA-expressing cells might be considered. Conversely, if PSMA avidity increases, PSMA-targeted therapies could be more effective.
### Summary:
After radiation, the relationship between PSA production and PSMA avidity can shift. These shifts depend on how the surviving cancer cells adapt and recover. Understanding these changes can provide valuable insights into the cancer’s behavior, guiding further monitoring and treatment strategies. Regular PSA testing combined with PSMA PET imaging will help detect and interpret these shifts effectively.
To your question of turn of events after imaging, yes imaging changed my treatment path. After unsuccessful salvage RT I was recommended for the STAMPEDE protocol. First, I went for imaging that identified five suspicious pelvic mets, no bone mets. After many consultations and lots of reading I chose reducing tumor burden with salvage pelvic lymph node surgery. That was over six years ago and I remain grateful I did the 'debunking'. Hope this helps. All the best!
If he will do the radiation of his pelvis he will not be able to do that surgery. I already recommended him to say no to the RO to pelvic radiation. Say that you have a terminal illness therefore not curable. You don't want to kill your bone marrow. Only radiate the prostate. They did radiate my both seminal vesicles and that has lots of bowel related side effects. They also wanted to radiate my pelvis but I said no thanks.
Thanks for weighing in. We talked about that, a be d I gave him one of your articles. I'm afraid my RO simply doesn't know very much at all about Provenge, so I asked him to reach out to my Provenge doctor. I also left voice mails for my Provenge doctor and my MO advising what my RO had said. I think he's inclined to do radiation after Provenge simply because he is being cautious.
Why do you think the PSMA showed no uptake outside the prostate? I was surprised, but didn't leap to any conclusion.
Provenge has a synergy with the sbrt radiation if you have the sbrt radiation just before provenge. I am not sure how critical the timing is but the immune sistem effect doesn't last long and it should be done parallel with provenge.
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PARP inhibitor Olaparib, phase 3 study findings (PROpel)
MRI prior to HDR Brachy and HDR intensity.
PSA holding low!!
