Your Gleason score
The Gleason classification system is the grading system most widely used to describe the degree of aggressiveness of the prostate cancer. Prostatic tissue, obtained by biopsy, is observed under a microscope where a pathologist evaluates the cancerous tissue and compares it to normal prostate tissue. Grading is based on two components: appearance and cellular arrangement. You may have heard talk of the Gleason grade and the Gleason score. Even if the two terms both describe the aggressiveness of cancer, they are not entirely synonyms.
The pathologist uses a scale from 1 to 5, the Gleason grade, to describe the degree of abnormality in the biopsied tissue samples. The lower the number (grade 1 or 2), the more normal the cancerous cells appear and the weaker the degree of aggressiveness. Inversely, the higher the number (grade 4 or 5), the more the cancerous cells will appear to be irregular or abnormal and the more severe the degree of aggressiveness. A grade 3 is given for an intermediate condition. However, as the prostate is not homogenous throughout the gland, different grades can be assigned within the same tissue.
The normal prostate tissue consists of a structured arrangement of ducts and small glands (acini). This is an image of low grade cancer.
This is an image of medium grade cancer. As the cancer cells multiply and spread, both the appearance and cellular arrangement will change. The cells change shape and begin to look less like typical prostate cells. This increase in activity also causes the cell nucleus, containing the genetic material for the maintenance, growth and reproduction of each cell, to become larger than normal. All of these changes cause the ducts and glands (acini) of the prostate to take on an irregular appearance.
This is an image of high grade cancer. These cancerous cells tend to behave very aggressively, that is to say they spread quickly. Normal cells die off as they compete against the cancer cells for nutrients. As high-grade cancer cells continue to spread, the ducts and glands (acini) of the prostate also disappear.
In the same tissue, cancer can be more aggressive in some areas than in others (different grades coexist). Thus, to get a more accurate idea of the cancer’s spread, the pathologist assigns the pathologist assigns grades to the two most common patterns of cancer growth and adds them together to get the Gleason score. It is important to consider the order of the grades. The first number represents the most common grade and can influence your choice of treatment..
For example, the degree of aggressiveness of a cancer with grades 3 + 4 (Gleason score 7) will be lower than a cancer with grades of 4 + 3 (Gleason score 7). In cases where a predominant grade cannot be found, the pathologist will add the number to itself. For example, 4 + 4 gives a score of 8.
The Gleason scale
In theory, the Gleason score is a scale from 2 to 10, but in practice, because grades 1 and 2 are not cancer, scores are normally only between 6 and 10 (3 + 3 to 5 + 5). In general, the higher the score, the more aggressive and fast-growing it is. The Gleason score can be an important factor in your doctor’s recommendation to proceed with a radical prostatectomy.
Your clinical stage
Your urologist will analyze all the results of the tests you have done and will give a stage for your cancer depending on the size and spread of the tumour. The most commonly used method for classification is the TNM method (Tumour, Nodes [lymph nodes], and Metastases).
The clinical stages of prostate cancer
T: Size and extent of the tumour
TX –Tumour cannot be assessed.
T1 – Tumour is small and confined to the prostate. The tumour cannot be felt during a digital rectal exam and although not visible on imaging, it can be seen under a microscope. This is a localized prostate cancer.
T2 – Tumour is contained to the prostate, but can be felt during a digital rectal exam or seen on imaging. This is a localized prostate cancer.
- T2a – Tumour has spread to half of the prostate lobe or less.
- T2b – Tumour has spread to more than half of only one of the prostate lobes.
- T2c – Tumour has spread to both prostate lobes.
T3 – Tumour has started to spread beyond the prostate to areas surrounding the gland. This is a locally advanced prostate cancer.
- T3a – Tumour has broken through the capsule of the prostate (the anatomical barrier that lines the exterior of the prostate), but has not spread to the seminal vesicles.
- T3b – Tumour has spread to the seminal vesicles.
T4 – Tumour has spread beyond the prostate to nearby structures other than the seminal vesicles: rectum, urethral sphincter, bladder, and pelvic wall. This is a locally advanced prostate cancer.
N: Spread to the nearby lymph nodes (pelvic)
NX – Regional lymph nodes are not measured.
N0 – No cancer cells in the regional lymph nodes.
N1 – Cancer cells present in the regional lymph nodes. Depending on the distance travelled by these cells (M stage), this is a locally advanced prostate cancer or an advanced prostate cancer.
M: Spread to distant sites (distant metastases)
MX – No assessment of distant sites or results are inconclusive.
M0 – No distant metastases
M1 – Distant metastases (bones, non-regional lymph nodes, liver, kidneys, lungs). This is an advanced prostate cancer.
The Union for International Cancer Control membership organization
The UICC groups the TNM data into four stages:
Risk of your prostate cancer spreading
Your cancer may be at low risk of spreading if:
- Your PSA level is less than 10 ng/mL, or
- You Gleason score is 6 or less, or
- Your cancer is stage T1 or T2a
Your cancer may be at medium risk of spreading if:
- Your PSA level is between 10 and 20 ng/mL, or
- Your Gleason score is 7, or
- Your cancer is stage T2b
Your cancer may be at high risk of spreading if:
- Your PSA level is higher than 20 ng/mL, or
- Your Gleason score is 8, 9 or 10, or
- Your cancer is stage T2c, T3 or T4
Your type of cancer
Localized prostate cancer
Localized prostate cancer is contained within the prostate, in other words it has not spread outside of the prostate. Many localized cancers are often not very aggressive and tend to grow slowly. Because of this, chances are high that this type of cancer will not cause you any problems in your lifetime. However, some localized cancers grow more quickly than others and can spread to other parts of your body.
There is no perfect treatment for localized cancer; each treatment has its strengths and weaknesses. A radical prostatectomy (the complete removal of the prostate) or a radiation therapy treatment can be done, but simply keeping a close watch can be enough to find any cancerous growths in time. Discuss the possible courses of treatment with your urologist.
Locally advanced prostate cancer
Locally advanced prostate cancer is cancer that has begun to break out of the prostate, but not too far. It may have spread beyond the boundaries of the prostate (capsule) into the neighbouring regions of the seminal vesicles, pelvic nodes, bladder, rectum, or pelvic lining.
Selecting the best treatment depends on the extent of the cancer’s spread.
- Active surveillance
- Hormone therapy
- Radiotherapy with hormone therapy with or without brachytherapy
- Radical prostatectomy, the complete removal of the prostate (in rare cases)
Advanced prostate cancer
Advanced prostate cancer, or metastatic prostate cancer, is cancer that has spread to other parts of your body — far from your prostate. Metastases originating from the prostate most often develop in the bones and lymph nodes. Bone pain, fatigue, and urinary problems are all symptoms associated of advanced cancer.
Advanced prostate cancer cannot be cured. There are, however, many treatments that can help to reduce symptoms and keep your cancer under control for several years. The preferred treatment for prostate cancer is hormone therapy.
The recurrence of cancer can happen when some cancer cells survive after your initial treatment. Cancer can recur in the same place or it can be detected in another part of your body. The latter is also known as a metastatic recurrence. The next treatment step depends on the location of the recurrence.
Hormone therapy can keep the spread of cancer under control for a number of years. However, with time, the cancer may become hormone resistant and start to grow again. That is to say, hormone therapy will become ineffective. The following terms are also used in reference to hormone-resistant prostate cancer: castrate resistant prostate cancer (CRPC), androgen independent prostate cancer, and hormone refractory prostate cancer. Treatments for hormone-resistant cancers exist, but are dependent on whether or not metastases are present.
Rare types of prostate cancer
The majority of men (95%) who have prostate cancer are diagnosed with adenocarcinoma, a malignant tumour in the glandular cells lining an organ. However, rare forms of prostate cancer also exist; the following are examples of such:
Leiomyosarcoma and rhabdomyosarcoma affect, respectively, smooth and striated prostatic muscle cells. These cancers don’t usually affect PSA levels, but often cause urinary problems. Sarcoma is found during biopsy, imaging or following a transurethral resection of the prostate used to treat urinary problems.
This cancer develops from neuroendocrine prostate cells. There are “small cell” neuroendocrine cancers and “large cell” neuroendocrine cancers that are much rarer and much less studied. Small cell carcinoma does not usually affect PSA levels and is often found following a biopsy or transurethral resection of the prostate that is used to treat urinary problems. This form of cancer tends to be aggressive, spreading to other parts of the body (metastases).
Transitional cell carcinoma
This cancer can start in the prostate, but more often than not, it starts in cancerous cells lining the urinary system (bladder, urethra, ureter, and kidney) and spreads to the prostate. This cancer is often diagnosed following a transurethral resection of the prostate.
Whether you are diagnosed with a rare form of prostate cancer or another less common type, such as ductal carcinoma, mucinous carcinoma, or signet ring carcinoma, ask your doctor to give you a detailed explanation of the cancer that you are affected by and its possible treatments.
Where can it spread
If my cancer spreads
Places where prostate cancer most commonly spreads
One of the characteristics of cancer cells is their ability to spread to other parts of your body from where they originally started growing. The spread of cancer can happen in three different ways:
- Local invasion: by growing, the tumour spreads into neighbouring tissues.
- Lymphatic spread: cancer cells break away from the tumour, enter into lymphatic circulation, and start growing in a new location.
- Hematogenous spread: cancer cells break away from the tumour, enter into the bloodstream, and start growing in a new location.
For the majority of cancers, places where the cancer usually spreads to are known and predictable. In the case of prostate cancer, cancer cells have a tendency to spread to the following places:
- lymph nodes located close to the prostate
- bone, especially the spinal cord, pelvis, femur, and ribs.
- lung (very rare)
- liver (very rare)
- brain (very rare)
The role of fatty tissues
Some studies suggest that the fatty tissues surrounding the prostate can help facilitate the spread of cancer to other parts of your body. Therefore, an obese man is more at risk of seeing his cancer spread beyond the prostate than a thin man.
Possible emergencies linked to the spread of cancer
The following are a few of the serious consequences that can result from the spread of cancer:
- Ureter obstructioncauses acute renal failure.
- Bladder outlet obstructionleads to trouble emptying the bladder.
- Brain metastasescause a variety of symptoms such as headaches and disturbances in mood, speech, movement, and internal bodily functions.
- Spinal cord compression results in weakness, numbness, or even paralysis of the legs.
We are here for you
Our urology healthcare professionals are there to listen, support and answer questions from patients, their families, the general public and healthcare professionals. Feel free to contact them.
Also take the time to visit each of our pages on this website, as well as our YouTube channel, in order to get familiar with the disease, with our expert lectures, our section on available resources, the support that is offered to you, our events and ways to get involve to advance the cause.