When Prostate Cancer Spreads: The Scans Doctors Use To Assess Advanced Disease

Some patients may be concerned about the radiation exposure from multiple scans. While this is a valid concern, it’s important to know that these scans are ordered with your safety in mind. The goal is always to gather the most useful information with the least risk possible.

Imaging Tests: What You Need To Know

Patients diagnosed with locally advanced prostate cancer — cancer that has spread just outside the prostate gland — or those with a higher Gleason score, which indicates a more aggressive cancer, are usually recommended to undergo more sophisticated forms of imaging.

These imaging tests are key to staging the cancer accurately and deciding whether surgery, radiation, hormone therapy, or a combination of treatments is most appropriate.

The most common scans a patient may receive as part of their prostate cancer workup include the following:

Bone Scan

One of the most commonly used scans for prostate cancer patients is the bone scan. This imaging test helps detect whether cancer has spread to the bones, which is a common site for prostate cancer metastasis. The scan involves injecting a small amount of radioactive tracer into a vein. This tracer travels through the bloodstream and is absorbed in areas where bone turnover is high, such as places where cancer may be growing.

However, bone scans are not always definitive. Other conditions, such as arthritis, bone infections, or past injuries, can also cause “hot spots” that appear on a scan, potentially leading to a false positive. That’s why bone scans are rarely used in isolation.

“Bone scans, unfortunately, can also sometimes be positive when someone has severe arthritis or other conditions, and so we need the use of multiple different modalities of imaging to help us determine whether there truly is cancer,” Dr. Janaki Sharma, a medical oncologist at Sylvester Comprehensive Cancer Center-University of Miami Health System, tells SurvivorNet.

Because of this, your doctor may recommend combining bone scans with other advanced imaging techniques for a more comprehensive assessment.

PSMA PET Scan

A newer and increasingly preferred option for staging prostate cancer is the PSMA (Prostate-Specific Membrane Antigen) PET scan. PSMA stands for prostate-specific membrane antigen, a protein found in high amounts on prostate cancer cells. This scan uses a radioactive tracer that binds specifically to PSMA, allowing doctors to see even very small areas of prostate cancer spread, often before they would show up on other types of scans.

This test is invaluable for men with high-risk prostate cancer, recurrent disease, or rising PSA levels after treatment. PSMA PET scans have revolutionized the field of prostate cancer imaging due to their high sensitivity and specificity, helping doctors detect cancer earlier and more accurately.

Axumin PET Scan and choline PET

Another advanced PET imaging option is the Axumin (fluciclovine F 18) PET scan. This scan uses a different radioactive tracer that is absorbed by prostate cancer cells. Axumin PET scans are typically used for men who have previously undergone treatment but now show signs that the cancer might be returning — usually indicated by a rising PSA level.

This scan can help detect where the cancer may be coming back, whether it’s still in the prostate area or has spread to lymph nodes or other organs. While not as sensitive as PSMA PET scans in some cases, Axumin PET is still a valuable tool and may be more widely available in certain locations.

While PSMA is currently considered preferable to both in most situations, both Axumin and choline are FDA approved agents. While many oncologists do not have strong preferences, other PET tests are available, including Axumin and choline.

CT Scan

The computed tomography (CT) scan is a well-established imaging technique that uses X-rays to create detailed cross-sectional images of the body. CT scans can be used to check for cancer spread to lymph nodes, lungs, liver, or other organs. It is often performed in combination with bone scans in the staging process.

CT scans are quick and generally widely available, but they may not always detect small areas of cancer, especially in lymph nodes. That’s why CT scans are often supplemented by PET imaging in high-risk cases.

MRI

For patients who are still in the early stages of diagnosis or who are undergoing active surveillance, a multiparametric MRI (mpMRI) of the prostate is often recommended. This scan provides highly detailed images of the prostate gland and can help identify suspicious areas that may need to be biopsied.

MRI is also useful in planning surgery or radiation therapy by helping to determine how far the cancer has extended and whether it has invaded nearby tissues. Some patients may also receive an MRI after treatment to assess for recurrence or complications.

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