Does SUVmax eventually go to zero after radiation to prostate?

[Steel67]

I had SBRT in August last year and latest PSMA PET scan shows same value 6.5 as before. Reading many papers online and no clear indication of time or scan results-expectations. Doc says let’s wait and see. Thank you

[Tall_Allen]

Eventually. But that's why imaging is meaningless (and is not FDA-approved) until there is a BCR or persistent PSA.

[dhccpa in reply to Tall_Allen]

Why meaningless after radiation? Isn't imaging the real indicator over PSA? And are talking about within the prostate gland or about distant metastases--or both? Thanks

[Tall_Allen in reply to dhccpa]

The OP asked about prostate gland radiation. Radiation created a lot of "zombie" cancer cells that look alive, but don't actually disappear until they undergo mitosis. Until then, BCR is a better indicator.

[dhccpa in reply to Tall_Allen]

OK, so you mean immediate scans. Or at least those done without waiting a decent interval. I saw you make a similar comment a week or so ago and it threw me. I think I'm understanding now.

[elwoodpdowd in reply to Tall_Allen]

BCR?? that is NOT on the abbreviation list. Thanks. My prostate cancer was successfully treated with SBRT and ADT in 2021.

[Tall_Allen in reply to elwoodpdowd]

BCR=Bio-Chemical Recurrence

[swwags]

every tumor is different and it can take weeks or months to fully resolve a lesion via SBRT. re-imaging is typically done 3 to 4 months following SBRT to determine effectiveness. Same value a year later seems odd to "wait and see" as SUV max of 6.5 isn't small. Perhaps request another radiologist read it and compare to previous scan? If it were me, that would be my first ask.

[maley2711]

For radiation without ADT, nadir PSA may not occur for many, many months. And the death of all cancer cells many not occur for many months......thus meaurable SUVMax remains for some time.

[dhccpa]

When was your latest PSMA scan? And when was the last one prior to radiation?

[Orange95 in reply to dhccpa]

For my husband his OR said at list 6 months for scans after RT. Also he going to do PSA test at list 8 weeks after RT. He said tests are useless right after, have to wait. So husband is getting full blood work done end of February to see how he recovers after RT which was completed on Dec31st.

[dhccpa in reply to Orange95]

Thank you.

[InqPers]

I went back and followed the SUV Max changes to my solitary bone met following radiation (IMRT, not SBRT).

Apr 2022: 10.4, Oct 2022: 4.3, Oct 2023: 1.7, Feb 2024: Complete resolution.

Of course, I had systemic therapies going on as well until Oct 2023.

[gardian_galaxie]

My understanding is radiation does not kill cancer cells, it damages their DNA preventing cells from dividing and multiplying. These cells can exist for more than a year. It would make sense (I'm not a doctor) the PSMA contrast is still targeting those cells and resulting in the SUV values. I also thought imaging (MRI & PSMA) were not used unless recurrence was suspected via PSA.

[j-o-h-n]

AI Overview

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SUVmax (Standardized Uptake Value Maximum) - *** Damn abbreviations***

SUVmax is a quantitative measure used in Positron Emission Tomography (PET) scans to assess the uptake of radioactive tracers in specific tissues or organs.

Calculation:

SUVmax is calculated as follows:

Code

SUVmax = (Activity in Region of Interest) / [(Injected Activity) / (Patient Weight)] [4, 5]

Interpretation:

Higher SUVmax values indicate greater tracer uptake in the examined area. This can be suggestive of:

Cancer (e.g., FDG-PET for cancer detection)

Inflammation

Infection

Clinical Use:

SUVmax is used in various clinical applications, including:

Cancer detection and staging: To identify cancerous lesions and assess their aggressiveness.

Treatment monitoring: To evaluate the response to cancer therapy.

Cardiac imaging: To assess myocardial perfusion and viability.

Limitations:

SUVmax is a semi-quantitative measure, and its interpretation can vary depending on factors such as the tracer used, imaging technique, and patient factors.

SUVmax values may not always be specific for cancer and can be elevated in other conditions.

Cut-off points for SUVmax can vary depending on the specific clinical context.

Conclusion:

SUVmax is a valuable tool in PET scans that provides quantitative information about tracer uptake. It is used in various clinical applications to aid in diagnosis, treatment monitoring, and prognosis. However, it is important to interpret SUVmax values cautiously and in conjunction with other clinical information.

SUVmax described in FDG PET-CT reports can provide information of ...

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Clinical significance of SUVmax in 18F-FDG PET/CT scan for detecting ...

Nov 24, 2015 — The maximum standardized uptake value (SUVmax) is widely used for measuring the uptake of FDG by malignant tissue (Gam...

National Institutes of Health (NIH) (.gov)

Maximum Standardized Uptake Value - an overview

However, SUVmax is so highly reproducible and easy to calculate that it is currently the most commonly utilized measure of FDG avi...

ScienceDirect.com

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This is for informational purposes only. For medical advice or diagnosis, consult a professional. Generative AI is experimental.

Good Luck, Good Health and Good Humor.

j-o-h-n

[elwoodpdowd in reply to j-o-h-n]

BCR?? it's NOT on the abbreviation list. thanks.

[j-o-h-n in reply to elwoodpdowd]

AI Overview

Learn more

Biochemical Recurrence (BCR) in Prostate Cancer

BCR refers to the detection of elevated prostate-specific antigen (PSA) levels after treatment for prostate cancer (PCa) with curative intent, such as surgery (radical prostatectomy) or radiation therapy.

Definition:

PSA level ≥ 0.2 ng/mL for two consecutive tests after surgery

PSA level ≥ 2 ng/mL after radiation therapy

Incidence:

BCR occurs in about 20-40% of patients after surgery and 10-20% after radiation therapy.

The risk of BCR is higher in patients with:

Higher Gleason score

Positive surgical margins

Advanced stage of disease

Management:

Active surveillance: Close monitoring with PSA tests, biopsies, and imaging (e.g., PSMA PET) is an option for low-risk patients.

Androgen deprivation therapy (ADT): This is the standard of care for high-risk patients and involves blocking the hormone androgen, which fuels PCa growth.

Salvage radiation therapy: This may be an option for patients with BCR after surgery.

Cryotherapy or high-intensity focused ultrasound (HIFU): These are less common treatment options.

Prognosis:

BCR is not always a sign of aggressive disease.

The majority of patients with BCR do not develop metastatic cancer or die from PCa.

However, the risk of progression is higher than in patients without BCR.

Additional Considerations:

It is important to discuss the risks and benefits of different management options with a qualified healthcare professional.

Patients should be aware of the potential side effects of treatments, such as ADT.

Regular follow-up and monitoring are crucial for early detection and management of any progression.

Biochemical recurrence in patients with prostate cancer after primary ...

Sep 7, 2023 — Nearly one-third of patients with prostate cancer (PCa) experience biochemical recurrence (BCR) after primary definitiv...

Nature

Management of Biochemically Recurrent Prostate Cancer After ...

Among men treated with prostatectomy or radiation therapy for localized prostate cancer, the state of an increasing prostate-speci...

National Institutes of Health (NIH) (.gov)

Biochemical recurrence (BCR) among patients (pts) with prostate cancer (PC) after radiation therapy (RT). | Journal of Clinical Oncology

ASCO Publications

Show all

This is for informational purposes only. For medical advice or diagnosis, consult a professional.

Good Luck, Good Health and Good Humor.

j-o-h-n