What Do Prostate Cancer Test Results Mean?
If you undergo a prostate biopsy, a pathologist will study the prostate tissue collected from each sample removed. These samples are referred to as cores and there are approximately 10-12 cores removed during each biopsy. The pathologist creates a report based on what they see in each core. Each core is studied under a microscope to see if cancer cells are present. The cores may be assigned a number or letter in order to determine where specific cell types or landmarks were found. If you have prostate cancer, it will typically be referred to as adenocarcinoma of the prostate. Adenocarcinoma is the most common type of prostate cancer and it develops in the cells that line the prostate gland.1
Gleason grade or Gleason score
The cancer cells in each core will be given a grade, called a Gleason grade, based on how closely they look like normal, healthy cells. When a core has cells that appear normal, they are given a grade of 1. The grades continue upward to a maximum grade of 5, in which the cells are very abnormal. Cells in cores with lower grades are said to be well-differentiated, and if they are deemed cancerous, they are less likely to be spread quickly (meaning they suggest that a man’s cancer could be less aggressive). Cells in cores with higher grades are said to be poorly differentiated and have a higher chance of being aggressive or spread quickly. The grades of each core are added to determine your Gleason score.
Your Gleason score is a combination of two numbers that can be written in a variety of ways. The first number represents the Gleason grade of the cancer cells that were most commonly found throughout your cores and the second number represents the next most common score of the cancer cells. These numbers may be written as a simple mathematic equation, such as 3+4=7, for a Gleason score of 7, or it may be written as 7/10 or 7 (3+4). Since 5 is the maximum Gleason grade, the highest score you can get is a 10 (5+5=10).1-3
Perineural invasion indicates that cancer cells were found around nerve fibers in the prostate. These cells could track along a nerve fiber, or could surround fibers completely. This finding indicates that there is a higher chance that the cancer has started to spread beyond the prostate. It is important to note, however, that just because perineural invasion is found, does not mean that your cancer has certainly spread.1
Other conditions that may be present
There are several conditions that can be found by chance during a prostate biopsy that are considered to be prostate pre-cancers. While research is ongoing in relation to how strong of an association these conditions have with developing prostate cancer, it is believed that several of these may predict future prostate cancer more than others. Most of these conditions aren’t treated, as few treatment options, if any, have been shown to decrease the risk of developing prostate cancer enough to justify their cost and risk. Although the same diagnosis may not be found in every core, the following findings are considered to be associated with an increased risk of developing, or already having, prostate cancer.
- Prostatic Intraepithelial Neoplasia (PIN)
- Proliferative Inflammatory Atrophy (PIA)
- Atypical Small Acinar Proliferation (ASAP)
- Glandular atypia
- Atypical glandular proliferation
Your report may also make mention of prostatitis, otherwise known as inflammation of the prostate gland. Prostatitis is non-cancerous, and often needs treatment with antibiotics. Your report may also mention atrophy (the shrinkage of prostate tissue which is often a result of certain prostate cancer treatments including radiation or hormone therapy), or adenosis. Neither of these conditions are cancerous nor typically treated. If you have questions about another condition that is found on your report, talk with your doctor.1,4-6
Other tests that may be run
There are other tests that may be run during your prostate biopsy, including p63, p40, ck5/6, ck903, 34BE12, PIN4 cocktail, AMACR (racemase), high molecular weight cytokeratin (HMWCK), or ERG. These tests may help diagnose or characterize your prostate cancer. Your doctor will be able to explain why any additional tests were run and what their results mean.1
Staging and TNM system
During diagnosis your prostate cancer may be assigned a stage. These stages are determined by a variety of information, including imaging results, prostate biopsy reports, PSA levels, and more. Prostate cancer is generally assigned a stage from I to IV (1 to 4), with I being less advanced and IV being more advanced. In order to determine your stage, you will be assigned to different TNM categories. TNM categories were created by the American Joint Committee on Cancer (AJCC).
These categories classify your case of prostate cancer based on the extent of the primary tumor found (T category), whether or not your cancer has spread to local lymph nodes (N category), and whether or not your cancer has spread to different parts of your body, also known as metastasis (M category). These categories and stages will help determine how your cancer may behave and what treatment options might be right for you.7,8