“You have prostate cancer.” Those words are scary, but in the majority of cases, the disease is diagnosed early when it is still contained in the prostate. This is called localized prostate cancer. (Prostate cancer is abbreviated as PCa in this blog.) Treating localized PCa has high success rates, because the gland is a single target that can be removed or destroyed.

However, sometimes at the time of diagnosis there is reason to suspect that PCa has already begun to spread. This is called advanced PCa. In either case, the most important thing is to find out where and how much of it there is. To do so, powerful imaging is needed to detect cancer spread wherever it may be in the body.

There are two other cases in which advanced PCa is suspected. In the first instance, the patient was already treated for high-risk localized PCa but now his PSA is rising. In the second, the patient is being treated for advanced PCa and powerful imaging is used to monitor treatment response.

How does prostate cancer spread and where does it go?

PCa spreads by tumor cells traveling in the bloodstream or lymphatic system. Most commonly it appears in the pelvic lymph nodes near the prostate gland, the lower spine, or the ribs. It can also spread to other organs such as the liver or lungs.

What types of imaging can detect advanced prostate cancer?

Today’s advanced imaging methods have produced two champions at detecting advanced PCa: Whole Body MRI (WB-MRI) and PSMA PET-CT.

WB-MRI is done in an MRI scanner. It uses a magnetic field and radio waves to generate 3-D images of the entire body. By adjusting specific settings to highlight tissue characteristics, differences between normal tissue vs. PCa tumors are seen with high resolution. Even small tumors will be visible in the prostate, pelvic bed, lymph nodes, bones, and other organs.

PSMA PET-CT is done in a CT scanner. PSMA stands for Prostate-Specific Membrane Antigen, a protein that is found on 90% of PCa cells. PET stands for Positron Emission Tomography. CT (computed tomography) uses radiation and a contrast agent to define structures in the body. For PSMA PET, a radioactive tracer is bonded with a substance that “sticks” to PSMA proteins on PCa cells. This tracer is injected into an arm vein so it circulates in the blood. When it sticks to PCa tumor cells, it acts like a contrast agent that the CT scanner picks up. This reveals the locations of advanced PCa anywhere in the body.

Is one imaging better than the other to detect advanced prostate cancer?

That’s like asking two champions to face off in a duel that can only end in a tie. Since WB-MRI and PSMA PET use different imaging methods, each one has a particular strength to offer.

On Nov. 6, 2025 the online newsletter Diagnostic Imaging issued a report, “Nine Takeaways from New Review of PSMA PET/CT and Whole-Body MRI for Advanced Prostate Cancer.” It summarized key points from a review of current evidence on both imaging types that was published in the journal European Radiology. Here are the main findings:

1. In patients with high-risk PCa, PSMA PET outperforms conventional CT scan and bone scan to identify pelvic lymph node involvement and distant metastases.
2. Another study comparing WB-MRI against conventional CT and bone scans demonstrated that WB-MRI did better for staging and risk stratification by detecting bone-only disease, high-volume disease and new metastatic disease. However, it did not do as well as conventional CT for identifying lymph-node only metastatic PCa.
3. One study of patients at high risk for metastatic PCa, a fast WB-MRI performed better than PSMA PET at detecting local tumors and distant spread.
4. In the same study, PSMA PET was superior to WB-MRI for detecting lymph node involvement.

The report noted this comparison: “While WB-mpMRI offers quantitative insights and high specificity for active disease, the researchers said PSMA PET offers detailed evaluation of metastatic tumor sites as well as prognostic correlations for progression-free and overall survival outcomes.”

Thus, individual doctors may prefer one over the other depending on the patient’s risk factors. Also, the availability of imaging may influence which scan a patient has, since not all centers are equally equipped, and rural areas in particular may be limited in imaging resources.

Finally, the Mayo Clinic notes that a best-case scenario may involve combining the two imaging methods: “PET combined with MRI is new and not available at all hospitals. Combining PSMA PET with CT or MRI makes it easier to see exactly where the tracer builds up in the body.”

When it comes to detecting advanced PCa, it doesn’t make sense to a face-off between them. Both of are champions at providing needed information. While each has its own strengths, the real winners are the patients. The earlier advanced PCa is identified, a treatment plan tailored to the patient can be developed, offering longer cancer control with higher quality of life.

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.