Tests You May Have to Detect Prostate Cancer Metastases

How Can You Tell if Prostate Cancer Has Spread?

A patient prepares for a CT scan.
A patient prepares for a CT scan.. Cultura RM/T2 Images/Getty Images

When prostate cancer metastasis -- spreading of the cancer outside of the prostate itself -- occurs, it typically affects the structures in its immediate vicinity.

Structures very near the prostate that are likely to be involved in prostate cancer metastasis early on include the seminal vesicles, urinary bladder, and bones of the pelvis. Lymph nodes near the prostate are also often affected.

Prostate Cancer Metastasis: Where Next?

Prostate cancer has a definite tendency to spread to the bones.

The bones of the pelvis, upper legs, and lower spine are the most common sites for prostate cancer bone metastasis, but all of the body's bones are potential targets.

Prostate cancer can involve the liver, intestines, brain, lungs, and other tissues as well, though these are far less common than the bones.

Why Would Prostate Cancer Metastasis Be Suspected?

Prostate cancer metastasis may be suspected if you have specific symptoms. For example, new lower back pain may raise your doctor's suspicion that you have metastasis to the lower spine, or newly elevated liver enzymes may cause your doctor to suspect spread to the liver.

Additionally, PSA levels that continue to rise despite treatment, especially if they are rising particularly fast, may raise your doctor's suspicion about the possibility of metastasis somewhere in your body.

How Is Prostate Cancer Metastasis Detected?

Imaging studies are the primary tool for this discovery.

A common imaging workup would include a bone scan and a CT scan of the abdomen and pelvis. Additionally, an MRI might be done. Some research centers are also using magnetic MRI's or PET scans to further refine the staging of prostate cancer.

Bone scan

A bone scan results in images of the entire skeleton.

Metastasis to the bone will usually show up as "hot spots" on the bone scan. There are many things which can cause "false positive" bone scans, so it's good to understand this before having a study done.

CT scan

A CT scan can be used to look for metastases in the abdomen and pelvis. Prostate cancer that has spread to the liver, intestines, or bones of the abdomen and pelvis can usually be found. Additionally, spread to the lymph nodes can sometimes be detected if the lymph nodes have become enlarged.

MRI

MRIs are sometimes used if there is a question as to whether the cancer has spread into tissues very near the prostate or to see if there is tissue left behind in the prostate bed following surgery.

Enhanced MRI

Using an enhanced MRI to look for prostate cancer metastases is a new area of research into finding difficult to detect spread to lymph nodes. This procedure uses an MRI after you are first injected with tiny magnetic particles a day before the scan. So far this appears to find spread of prostate cancer to lymph nodes which would not have been detected by a regular MRI alone.

PET scan

A PET scan is an imaging test that looks at function as well as anatomy. It is often combined with a CT scan. In this procedure you are injected with a small amount of radioactive sugar. Cells which are actively growing -- such as cancer cells - take up this sugar and light up on exam. With some cancers, PET scans add information that helps with staging that isn't available with other imaging tests we have.

Sources:

American Cancer Society. Preventing and treating prostate cancer spread to bones. Updated 03/12/15.

American Cancer Society. What’s new in prostate cancer research and treatment? Updated 10/23/15.

Govindan R, Arquette MA. Washington Manual of Oncology. 2002.

Abraham J, Gulley JL, Allegra CJ. Bethesda Handbook of Clinical Oncology. 2005.

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