What is the difference between localized prostate cancer and metastatic prostate cancer?

Prostate cancer, the most common non-skin cancer among men, begins with mutations in healthy prostate cells. At the time of diagnosis, if prostate cancer is still contained in the gland, it is called localized prostate cancer. When localized prostate cancer is treated, success rates at 5 years are greater than 99%.

However, if prostate cancer is left untreated, it can spread to distant bone or organs. This is called metastatic prostate cancer, or simply metastasis. At this stage, it is considered incurable. The goal then becomes to identify the areas of metastasis in order to strategize treatments to prolong life.

How can a patient know if he has metastatic prostate cancer?

In most cases, the first hint that prostate cancer has metastasized is a high PSA (prostate specific antigen) blood test result. Just as normal prostate cells release PSA into the blood stream, so do prostate cancer cells.

Typically, the more prostate cancer in the prostate and elsewhere, the higher a PSA test result is likely to be. Although other noncancerous conditions can also cause PSA to rise, a dramatically high or rising PSA can mean suspected metastatic prostate cancer.

There is no fixed PSA number that automatically means metastasis. MD Anderson Cancer Center offers these general guidelines:

Technically, there is no upper limit. PSA levels can go into the tens or even hundreds of thousands. But generally speaking, these are the ranges of elevation: 

• 4-10: minimally elevated
• 11-20: moderately elevated
• 21+: high elevation

Your doctor will likely investigate anything over 10. Anything greater than 20 starts pointing more toward cancer. Anything above 50 is usually a very strong indicator of prostate cancer. Levels that high are usually not due to an infection or some other thing going on. 

How can we know if metastasis is really present?

A high PSA is suspicious for metastasis, but it is not definitive. For accurate detection, today’s advanced imaging is needed. In particular, multiparametric MRI and PSMA-PET scans are the preferred imaging methods. They are both superior to conventional CT scans and bone scans for identifying metastasis.^[i] 

Both types of imaging are excellent for detecting prostate beyond the gland, including the prostate bed, lymph nodes, bones, other organs. This noninvasive imaging has reduced the need for exploratory surgery. Thus, imaging has an essential role because it can reveal metastasis, even if small.

Are there differences between mpMRI and PSMA-PET for detecting metastasis?

Both imaging methods have comparable results, but each has a particular strength. Findings often agree between the two, and sometimes they complement each other.^[ii] At times, one might have an advantage over the other, though studies vary.^[iii]

In some cases, whole body mpMRI (WB-MRI) may have better detection than PSMA-PET. For example, a 2025 study using a faster type of WB-MRI found it had rates for detecting local tumors (87% vs. 77%) as well as metastatic disease (19% vs. 11%).^[iv] 

WB-MRI may also be useful for predicting risk. Yoshida, et al. (2020) calculated that the extent of bone metastasis and tumor presence in organs as seen on WB-MRI (specifically diffusion-weighted imaging) were linked with shorter cancer-specific survival.^[v]

On the other hand, PSMA-PET was shown in some studies to have higher detection rates of lymph node involvement. Nieuwenhove, et al. (2025) demonstrated that PSMA-PET had better detection of lymph node involvement vs. WB-MRI (40% vs. 29%).

Is this type of imaging useful for planning treatment?

Today’s advanced imaging is a powerhouse for identifying suspected metastasis after a high PSA test result. Although metastatic prostate cancer is considered incurable, patients should not lose hope. According to UCLA Health, “there are effective ways to help slow its spread, prolong life, and control its symptoms, including immunotherapy, hormone therapy, chemotherapy, precision medicine and clinical trials.”

Thanks to either WB-MRI or PSMA-PET, knowing the location and extent of metastasis allows planning a strategy best suited to control each patient’s disease. Regardless of which imaging method is prescribed, each of these technologies is a powerhouse, revolutionizing the detection of prostate cancer metastasis.

Can WB-MRI or PSMA-PET track the effect of treatments?

Yes, both types of imaging are useful for monitoring treatment effects. However, according to a presentation delivered to the 2025 Advanced Prostate Cancer Consensus Conference (APCCC) by international expert Dr. Joe O’Sullivan, “For managing treatment, …both whole body MRI and PSMA PET are adequate, with whole body MRI slightly better.”^[vi]

Summary

In conclusion, whole body MRI and PSMA-PET perform comparably to identify suspected prostate cancer metastasis, plan treatment, and monitor treatment effect. Whole body MRI appears slightly better at detecting metastasis, predicting risk, and tracking treatment response.

Frequently Asked Questions

Q: If metastatic prostate cancer is considered incurable, why is imaging important?

A: Imaging, especially Whole Body MRI (WB-MRI) provides accurate information on the location and extent of metastatic prostate cancer. Though the disease is considered incurable, today there are more clinical methods than ever before to control the disease and prolong life. The earlier imaging is done, the more treatment options are available. Thus, it’s important to detect and define metastasis as soon as possible.

Q: Is all metastatic prostate cancer identical?

A: While many cases of prostate cancer metastasis may appear similar, in a very real sense no two cases are exactly alike. Some cases are diagnosed when they are still responsive to hormone therapies to cut off testosterone; some cases have more sites of metastatic tumors than others; some cases involve gene variants that can determine if immunotherapy will be effective; some cases need different drug “cocktails” at different doses or intervals. That’s why it’s important to take many clinical factors into account, not just location and extent revealed by imaging.

Q: What are examples of other clinical factors besides imaging?

A: Some factors that have a bearing on treatment planning include family history, patient age, overall patient health and co-existing conditions, tumor genomics, and history of previous treatment. The patient’s medical team will determine which records and tests are necessary to plan treatment.

Q: What treatments are available for metastatic prostate cancer?

A: There are several categories of treatments depending on each patient’s clinical factors.

• Hormone therapy (androgen deprivation therapy) for metastasis that is sensitive to hormones
• Immunotherapy
• Chemotherapy
• Biologically targeted treatments (radiopharmaceuticals)
• Treatments in clinical trials

Patients should not give up hope, since many new treatments are still in clinical research and development.

Content reviewed by Dr. Dan Sperling, M.D., DABR — updated November 2025

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Woo S, Russo L, Withey SJ, Dehghanpour A et al. ESUR: Opportunities for PSMA-PET/CT and whole-body MRI in advanced prostate cancer. Eur Radiol. 2025 Nov 5.
[ii] Cattabriga A, Renzetti B, Galuppi F, Bartalena L et al. Multiparametric Whole-Body MRI: A Game Changer in Metastatic Prostate Cancer. Cancers (Basel). 2024 Jul 13;16(14):2531.
[iii] Woo et al., ibid. 
[iv] Nieuwenhove SV, Lhommel R, Pasoglou V, Damme JV et al. Fast (< 30 min) "All-in-One" whole-body MRI for TNM staging in high-risk prostate cancer (PCa): Feasibility and comparison to 68Ga-Prostate Specific Membrane Antigen (PSMA)-PET/CT. Eur J Radiol. 2025 May;186:112033. 
[v] Yoshida S, Takahara T, Ishii C, Arita Y et al. METastasis Reporting and Data System for Prostate Cancer as a Prognostic Imaging Marker in Castration-resistant Prostate Cancer. Clin Genitourin Cancer. 2020 Aug;18(4):e391-e396. 
[vi] Klaassen, Z. “APCCC Diagnostics 2025: What Do You Want to Have Reported in MRI and PSMA PET?” UroToday. https://www.urotoday.com/conference-highlights/apccc-diagnostics-2025/158680-apccc-diagnostics-2025-what-do-you-want-to-have-reported-in-mri-and-psma-pet.html 

About Dr. Dan Sperling

Dan Sperling, MD, DABR, is a board certified radiologist who is globally recognized as a leader in multiparametric MRI for the detection and diagnosis of a range of disease conditions. As Medical Director of the Sperling Prostate Center, Sperling Medical Group and Sperling Neurosurgery Associates, he and his team are on the leading edge of significant change in medical practice. He is the co-author of the new patient book Redefining Prostate Cancer, and is a contributing author on over 25 published studies. For more information, contact the Sperling Prostate Center.