Prostate Cancer Staging (And Why We Don’t Really Use It)

One of my prostate cancer patients recently asked me what his stage was. It’s an appropriate question, of course, but I had to explain that prostate cancer staging isn’t really used by oncologists as much as other cancer stages.

While your oncologist (urologist, radiation oncologist, or medical oncologist) can calculate a “stage” for you, prostate cancer is a slow-growing cancer and, biologically, behaves differently than other cancer types. For this reason, we use other scientific data to put you in a risk category. If you really want to know your stage, check out the American Cancer Society’s table
or ask your oncologist.

Prostate Cancer Risk Category

Major changes were made to prostate cancer staging in the AJCC 8th Edition Staging manual which was released in January 2018. Staging needed to be updated to reflect the fact that tumor biology now trumps anatomy. Historically, staging has focused on anatomy (the size of the tumor, the number of lymph nodes involved). The new changes are similar to the risk category and, therefore, more reflective of the cancer biology, how the tumor will behave. With advances in MRI, we can see small tumors in the prostate, many of which just sit there and never become a problem. Others may aggressively spread to lymph nodes or the bone, requiring a swifter and more aggressive form of treatment.

The risk category continues to be used as the standard in prostate cancer treatment. Every oncology resident has had to memorize D’Amico risk categories, but like so many things, it’s easier to just use an online calculator or app.

The Role of Prostate Cancer Risk Categories Today

While AJCC staging has historically focused on the size of the tumor (T stage), number of lymph nodes involved (N stage) and if the cancer has metastasized (M stage), the latest scientific research has shown us that it’s the biology of the tumor that predicts the cure rate and therefore the treatment. Part of the risk categorization is looking at the Gleason Score and the PSA. These are biologic indications of how aggressive the prostate cancer cells appear under the microscope.

For example, a man could have an elevated PSA (prostate specific antigen) blood test on his yearly physical. He will likely be referred to a Urologist who will continue to check the PSA to see if there is an persistent elevation. If the patient and the Urologist are concerned, an MRI will be ordered to see if there are any obvious tumors in the prostate as well as any enlarged lymph nodes that might have cancer in them. A prostate biopsy will also be completed to see if any cancer cells are detected.

Here’s the issue, most men will have prostate cancer cells on biopsy, especially if they are over 70. BUT….are these cells or tumors ever going to cause a problem? Turns out we all have cancer cells in our bodies…hopefully our immune systems take care of these cells, much in the same way as we deal with infections.

Determining You Prostate Cancer Risk Factor

As an oncologist, I have to figure out which prostate cancers are the bad actors. Which cancers will metastasize to the lymph nodes and the bones. It’s tricky, because regardless of the “stage” of cancer, whether the cancer is on both sides of the prostate or even outside of the gland, it’s the aggressiveness of the cancer that determines prognosis, as well as treatment. So, to determine the best course of action, I look at the Gleason Score (how aggressive the cells appear under the microscope), how rapidly the PSA has risen, as well as the patient’s family history and whether they are African-American or not. Each of these factors gives me an indication of how aggressive the prostate cancer may act and how aggressive I need to be with treatment. In addition, genetic testing is now available that examines the actual tumor genes to see how the tumor may respond to treatment.

In summary, determining which stage of prostate cancer a patient has is a different task than it was in years past. Today, prostate cancer staging has changed to be more reflective of the biology of the cancer and how we anticipate it will behave. With that said, remember that your cancer is as unique as your fingerprint and, consequently, recommendations for treatment will be as well. I encourage all of my patients with prostate cancer to meet with both a surgeon (Urologist) as well as a Radiation Oncologist to ensure that they understand both surgical and non-surgical options.

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