The diagnosis of prostate cancer can be disturbing, just like any other. Prostate cancer is, unfortunately, one of the most common types of cancer in men.
The risk increases as we age, and a large number of men are diagnosed before age 80 years. If there’s anything positive to say about this urological pathology, it would be about its aggressiveness rate.
In most cases, older adults diagnosed with this problem will die from natural causes or any other reason besides prostate cancer. But others are not so lucky, with an aggressive type that grows rapidly and causes severe consequences.
Since prostate cancer is variable in every individual, doctors need to have a way to describe each case. That’s when staging becomes useful. It gives a solid idea of what type of cancer we are dealing with and what to do next.
Undoubtedly, every patient has an individual experience with prostate cancer, but staging gives your doctor an appropriate first glimpse to guide his recommendations.
However, all of this staging medical jargon indeed sounds difficult. Then, you want to know what your doctor is talking about because you feel worried about it. If that’s your case, keep reading this article as we walk you through the most important aspects of prostate cancer staging.
We’re covering the most common types of staging systems, how doctors group cancer patients, and what risk factors we should consider.
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Types of staging for prostate cancer.
Staging is a standardized way for doctors to communicate where cancer is located. With a combination of numbers or letters, cancer staging describes the disease. Is it encapsulated in the prostate? Has it spread to nearby places in the pelvis? Has it spread to distant places? How aggressive is it?
Doctors stage prostate cancer by examining patients and ordering diagnostic tests. Since staging depends on tests and physical exams, you need to complete them before turning to the next step.
Imaging tests are crucial for this particular matter. They determine if cancer is stuck in the same place or has spread to other parts of the body.
This staging is basically of two types (1)
A clinical-stage: It is the first staging a prostate cancer patient gets. You don’t need a prostate biopsy for this. What you need is a combination of Gleason scores, PSA levels, and a digital rectal exam.
After this, and looking at the results, your doctor will decide if other exams are required. If your cancer has signs of aggressiveness, your doctor will probably order bone scans or a CT scan. You may even get an MRI in some cases. Your doctor will continue evaluating your stage with these tests.
A pathologic stage: This is a more advanced staging that requires a prostate biopsy or surgery. The radical prostatectomy specimen is taken to the lab and immediately analyzed to evaluate what type of cancer we’re facing.
In aggressive cancer stages, doctors prefer to remove the entire prostate. The lymph nodes may also be removed, depending on each case. In some patients, lymph nodes are also taken to the laboratory to contribute to the staging process.
You don’t always need to have both types of staging to manage your prostate cancer appropriately. Prostate biopsies provide great information to establish the diagnosis and start treating cancer.
However, depending on the patient’s age, doctors may decide not to perform a prostate biopsy. They have side effects such as rectal bleeding, chronic pain, and urinary problems. So, your doctor won’t make you go through this procedure if you’re not going to benefit from it.
Now, let’s go through two of the most critical staging systems in prostate cancer. They are the TNM system and the Gleason score.
TNM stands for Tumor, Node, and Metastasis. It is a staging system developed by the American Joint Committee on Cancer. It is commonly used in most types of cancer regardless of the country and language.
Depending on the stage, each letter in TNM describes characteristics of the primary tumor, the lymph nodes, and any metastasis event. So, we can say that TNM staging gives information about (2,3,4):
T, for the tumor
Depending on the number that goes after T, we can describe a smaller or bigger tumor. We can also define the location of cancer and whether it has taken nearby structures.T1: This is the smaller prostate cancer tumor you can have. It can be divided into T1a, T1b, or T1c.
As for T1a and T1b, they describe a type of cancer found in less than 5% or more than 5% of the prostate, respectively. They are usually casual findings after removing the prostate for BPH or any other problem. T1c cancer is found in a prostate biopsy when you have a high PSA or any other alarm sign.T2: This type of cancer is bigger but still enclosed in the prostate gland. It can be divided into T2a, T2b, or T2c.
For this prostate cancer staging, the gland is split into two halves.
- T2a cancer is found in less than 50% of one side of the prostate. T2b cancer is found in more than 50% of one side. As for T2c, it is found in both halves of the prostate but still enclosed in the capsule.
- T3: This type of cancer is bigger still, and it is not limited by the prostate capsule. It can be divided into T3a and T3b, depending on whether it has taken the seminal vesicles.T4: This is a bigger prostate cancer that invaded nearby organs. It has taken the rectum, the pelvic wall, the bladder, or a similar structure.
N, for the lymph nodes
Depending on the number that goes after N, doctors describe if the disease takes lymph nodes. How many lymph nodes are taken by cancer? Which ones are taken? The N part of TNM gives all of this information.
- N0: It means that no nearby lymph nodes are taken by prostate cancer.
- N1: It means that one or more lymph nodes are taken by prostate cancer. When lymph nodes are taken, doctors make further clarifications to indicate which ones.
M, for metastasis
Depending on the number that goes after M, doctors describe if the patient has metastasis. If they do, the TNM system may also provide information on how bad is it.
- M0: It means that there is no trace of metastasis in other parts of the body.
- M1: It means that there is traceable metastasis in other parts of the body. Depending on the severity, it can be divided into M1a, M1b, or M1c. We call it M1a when distant lymph nodes (outside of the pelvis) are taken. M1b is a type of prostate cancer that metastasizes in the bone. M1c is the final metastasis stage, where other organs are taken by cancer cells.
Another useful tool to stage prostate cancer is the Gleason score or Gleason grade system. However, not all patients get a Gleason score because it requires taking a cancer sample to the microscope.
As noted above, some prostate cancer patients may be recommended not to go through a prostate biopsy. For example, after 80 years old, patients with very fragile health may further compromise their quality of life after a prostate biopsy. As for the rest, a prostate biopsy is required to establish the diagnosis of prostatic adenocarcinoma. Then, Gleason scores become an exceptional tool to guide the treatment.
What the Gleason score does is looking at the prostate cancer sample and evaluating cancer cells. How do they look like? Are they significantly different from normal cells? Or maybe they are very similar and difficult to make out. The more aggressive cancer is, the more it stands out from the rest of the prostate tissue. In contrast, nonaggressive tumors look similar to normal tissue.
That’s why the Gleason score is so widely used in clinical practice. It helps doctors with the prognosis of the disease and evaluates how dangerous it is. But how is it done.
After receiving the prostate sample, the pathologist at the lab evaluates 2 locations. For each one, he would assign a number from 3 to 5.
- The number 3 is given to cancer cells that look very similar to normal prostate cells.
- The number 5 is given to prostate cancer cells that look extremely different from healthy tissue.
- Number 4 is in-between both extremes. The numbers from each location are then added together. The result is a score that goes from 6 to 10. According to other authors, you can have a score lower than 6, but that’s not very common.
- So, you could say that a Gleason score 6 and lower mean low-grade cancer. It is more likely to progress slowly, and some patients with this type of prostate cancer die from other causes.
- Scoring 7 means you have medium-grade cancer, which should not be neglected. But if you score 8, 9, or 10, it’s because you have high-grade cancer. This type is very dangerous because it spreads rapidly if not properly handled.
Gleason score is a valuable tool to make treatment plans. Depending on the patient and the score, active surveillance may be recommended. That’s a common approach in low-grade cancer.
But advanced prostate cancer may require surgery (radical prostatectomy), radiation therapy, and sometimes hormone therapy. Along with the Gleason score, PSA levels are fundamental to guide the treatment protocol (3,4,5).
Gleason Grade Groups
In short, we can break down the Gleason grading system into three to four different Gleason Grade Groups:
- G1: It is a well-differentiated cancer tissue. Cancer cells look very similar to the healthy tissue, sometimes difficult to make out. Gleason score in G1 is 2-4, and it is low-grade prostate cancer. As noted above, G1 grading is uncommon, and most patients have a score of 6 as the minimum.
- G2: Cancer tissue is moderately differentiated. In other words, cancer cells are easy to make out, but they are somewhat similar to healthy tissue. Gleason score in G2 patients is 5-6. We can say this is still low-grade prostate cancer.
- G3 and G4: Cancer tissue is poorly differentiated or completely undifferentiated. In other words, cancer cells look extremely different from healthy tissue. Gleason score in G3 and G4 patients is 7-10. It can be a medium-grade or high-grade cancer.
Cancer stage grouping
The next step after receiving the TNM stage, the Gleason stage, and the PSA result is assigning a stage group. This prostate cancer stage grouping combines different staging systems to reach more accurate conclusions.
It can be divided into 4 stage groups with increasing severity as the number goes up (4,5):
This is an early stage of cancer, usually slow-growing and low-grade. This tumor combines a low TNM stage, a low Gleason stage, and low PSA levels. In the TNM stage, the tumor can be T1 or T2a-b, but never T2c or T3. PSA levels are usually lower than 10, and the Gleason score is 6 or lower than 6.
So, this is a low-grade prostate cancer without signs of aggressiveness.Stage II: In this stage, prostate cancer is enclosed in the prostate. It is usually medium-grade cancer with or without alarm signs.
It can be divided into two or three, depending on the author:
During this stage, we have medium-grade cancer. Once again, we can have a T1 or T2a-b stage in TNM, but not T2c or T3. PSA levels are usually around 10 and 20, and the Gleason score is 6 or 7.
This stage also features medium-grade cancer because Gleason scores are 6 or 7. However, some authors say that stage IIB can have a higher Gleason score. What remains the same is that the TNM score is either T1-2, including T2c, but never T3. The PSA levels are usually higher than 20.
This stage is exactly the same as the one above. The only difference is that the Gleason score is higher than 7. It is usually 8 or 9.
In this stage, cancer is growing and showing signs of aggressiveness. The PSA levels are usually high, and the Gleason score is high, too. It is also subdivided into A, B, and C, depending on the tumor’s location.
High PSA levels. Prostate cancer already spread to nearby tissue. The seminal vesicles are taken. No lymph nodes are taken, and there’s no sign of metastasis.
High PSA levels. Prostate cancer spreads to nearby tissues. The rectum, bladder, and other local organs are taken. No lymph nodes are taken, and there’s no sign of metastasis.
High PSA levels. Prostate cancer spreads to nearby tissues. No lymph nodes are taken, and there’s no sign of metastasis. The Gleason score is very high because the cells are poorly differentiated.
In this stage, cancer is beyond the prostate. Regardless of the Gleason score and the PSA levels, it has either taken the local lymph nodes (Stage IVA) or distant lymph nodes and/or distant organs (Stage IVB).
Besides these stages, there’s also recurrent prostate cancer when it comes back after treatment. It can attack the prostate or any other organ. Sometimes, there are no physical signs, but tests point out at prostate cancer recurrence. This is known as biochemical recurrence.
Prostate cancer risk factors
Throughout this article, the prostate biopsy was highlighted as an essential step in diagnosing prostate cancer. But the prostate biopsy is only performed after the screening of a suspicious case, and screening is only performed in patients with a high risk.
The most important risk factors include (6):
- Age: As we age, the risk of prostatic carcinoma increases. It is one of the most common types of cancer in aging males. 80% of cases are diagnosed in men after 65 years of age.
- Family history: Prostate cancer has a genetic link. If you have close male relatives with prostate cancer, you have a higher chance of having the same problem.
- Race: Males of African American descendancy have a higher rate of prostate cancer. They may also have a higher rate of aggressiveness.
A combination of various staging systems determines the prostate cancer grade. The most important include the TNM staging system, the Gleason pattern score, and the PSA levels.
The TNN system describes the extent and size of prostate cancer. It also depends on whether or not it has taken lymph nodes or distant organs. The Gleason score evaluates how cancer looks like in the microscope.
When prostate cancer cells are very different from healthy tissue, there’s a higher chance of aggressiveness. And the PSA levels are different from one patient and the other, but they are useful to evaluate the prognosis.