What Does the Term ‘Clinically Significant’ Prostate Cancer Mean?

At Lynx Dx, we often use a phrase that may be unfamiliar to many readers: “clinically significant” prostate cancer. It’s a common term in urology, the medical field that studies, diagnoses and treats prostate cancer, the most-diagnosed type of cancer among men in the United States.

But it may raise questions for patients. Does this imply that only some cancers matter? Are some prostate cancers clinically insignificant? What does that mean?

In order to explain the term, let’s first describe the process of diagnosing prostate cancer.

Screening

Prostate cancer screening typically includes a prostate-specific antigen (PSA) test, a blood test that looks at levels of the protein, which may indicate the presence of prostate cancer.  Physicians may also conduct a digital rectal exam (DRE) or other screening methods such as a biomarker screening.

If there are abnormal results from your screening tests, a physician may order a prostate biopsy, where a small sample of tissue from the prostate is removed so it can be examined to see if there are any cancer cells. A prostate biopsy has historically been the main method of diagnosing prostate cancer.

Detection of clinically significant prostate cancer

A doctor determines that prostate cancer is clinically significant when it is aggressive, likely to spread if not addressed and presents a risk to the patient. In these cases, doctors recommend the patient undergo immediate treatment.

Determining whether or not your prostate cancer is clinically significant involves an evaluation based on scientific criteria, which your doctor may reference:

• Looking to see how healthy your tissue looks from a biopsy. Physicians assign a sample a Gleason score, which reflects how much the cancer resembles normal, healthy cells and how likely it is to grow and spread, of between 6 and 10.
• Cancer staging is used to determine how extensive and serious the cancer might be, including whether it has spread to other areas of the body. Physicians use the TNM staging system, short for tumor, node and metastasis, to determine these factors.
• Measuring the tumor’s volume.

Low-risk prostate cancer, commonly referred to as “clinically insignificant” cancer, refers to cancer that is considered small, limited to the prostate, slow-growing and unlikely to affect a patient in his lifetime. Physicians in this case generally recommend active surveillance to closely monitor the cancer, rather than more aggressive surgery or radiation therapy. In active surveillance, physicians will do regular tests to monitor the cancer.

Shared decision-making

In recent years, we’ve learned that fewer than 25% of all prostate cancers are clinically significant following an elevated PSA; the rest are considered slow growing and unlikely to spread, making them good candidates for active surveillance.

To help determine whether a patient potentially has clinically significant cancer in less invasive ways, there are new blood- and urine-based tests that patients can take following an elevated PSA. These tests can help identify whether the elevated PSA is due to clinically significant cancer, which helps guide patients and physicians on whether a biopsy is needed or if a patient can continue with active surveillance.

These new advances give patients and their physicians solid insights to aid in shared decision-making about the best course of treatment — whether or not prostate cancer is determined to be clinically significant.