One in eight men will be diagnosed with prostate cancer during his lifetime, making it second only to skin cancer as the most common cancer affecting American men. The good news is that the 10-year survival rate for localized prostate cancer—disease that hasn’t traveled outside the prostate—is nearly 100 percent, according to data collected between 2001 and 2016 and analyzed by the U.S. Centers for Disease Control and Prevention (CDC). Increased awareness, multiple screening and diagnostic tools, advanced surgical techniques and other factors have contributed to producing positive outcomes for many men diagnosed with prostate cancer. More than 3 million American men are living with the disease, according to the National Cancer Institute (NCI).
One of the tools doctors use to diagnose and stage prostate cancer is called a Gleason score—a critical calculation designed to help determine the extent of the disease, the aggressiveness of the cancer cells and how it may be treated. In this article, we’ll explain the Gleason score and how it may be used in the fight against prostate cancer. Topics include:
- What is the Gleason score?
- What is prostate cancer
- What’s the difference: Gleason score vs. PSA test
- What are the screening recommendations for prostate cancer?
If you’ve been diagnosed with prostate cancer and want to explore your treatment options, or if you’re interested in a second opinion on your prostate cancer diagnosis and treatment plan, call us or chat online with a member of our team.
What is the Gleason score?
Since the 1960s, doctors have relied on the Gleason grading system to assess the aggressive nature of a particular prostate tumor. Named for Dr. Donald Gleason, the pathologist who devised the grading system, a patient’s Gleason score helps doctors more accurately determine:
- The grade of the disease, its biological activity and aggressiveness
- The stage of the disease, how much of the prostate is involved and how far has the disease spread
Knowing the grade and stage of the prostate cancer may help doctors determine which treatments may produce better outcomes.
To calculate a Gleason score, a pathologist uses a microscope to examine tissue samples retrieved during a prostate biopsy. The pathologist will assign scores ranging from 1 to 5, depending on the cancer cells’ appearance.
Gleason score 1 is used when cancer cells look very much like healthy cells.
Gleason score 5 is used when cancer cells look very abnormal.
The scores of the most common pattern and the second predominant pattern found among cancer cells will then be added together to create a combined Gleason score, also called the Gleason sum.
Gleason sum of 6 or lower indicates the cancer cells may be less aggressive.
Gleason sum of 8 or higher indicates the cancer cells may be more aggressive and more likely to grow and spread.
Doctors use the combined score and the way it’s calculated to determine which of the five grade groups should be used to categorize the cancer, with grade group 1 being the least aggressive. Two patients can have the same Gleason sum but be in two different grade groups.
For instance:
If the Gleason sum is 7, where the most common pattern has a Gleason score 3 and the second-most common pattern has a score of 4, the patient's disease would be in grade group 2.
If the Gleason sum is 7, where the scores are reversed and the most common pattern has a Gleason score of 4 and the second-most common pattern has a score of 3, the patient's disease would be in grade group 3.
The grade group is eventually used to determine the stage of the disease.
“Once you know your Gleason score and grade group, your doctor can determine your clinical status, and whether you’re a surgical risk or have co-morbidities,” says Bradford Tan, MD, Chair of the Department of Pathology and Laboratory Medicine at Cancer Treatment Centers of America® (CTCA) and Chief of Staff at CTCA® Chicago. “All of this should be discussed with the treating physician.
“Prostate cancer has more data points than other cancers,” he continued. “If you have early prostate cancer, say a score of 6, depending on the presence of co-morbidities or surgical risk, you may just need active surveillance. If you’re a 9 or 10 with metastatic disease, you will most likely need to take hormones or undergo an orchiectomy (surgical removal of the testicles) to control hormone production because the tumor has already spread beyond the prostate. If your score is in-between, you and your oncologist have to decide how to proceed.”
What is prostate cancer?
The prostate sits at the base of the bladder, behind the rectum and attached on the top and bottom to the urethra, the tube through which urine and semen flow through the penis. The gland, found only in men, produces some of the fluids in semen. The prostate is about the size of a walnut, but gradually gets larger as men age. Over time, many men may face certain conditions related to the prostate, including:
- Enlarged prostate, when the prostate grows large enough to cause urinary system issues
- Benign prostatic hyperplasia (BPH), when enlarged prostate tissue is replaced by scar tissue
- Prostate cancer, when cells in the prostate mutate or become damaged and grow out of control
Because the symptoms of all three of these and other prostate conditions are similar, it’s important for men to see a doctor if one or more of them develop and persist. An accurate diagnosis is critical to determine whether the symptoms are caused by prostate cancer or another condition affecting the gland or the urinary tract.
Symptoms may include:
- Difficulty urinating
- More frequent need to urinate, especially at night
- Weak urine stream
- Urinary tract infections
- Weak or painful ejaculation
- Blood in the urine
If a man is diagnosed with prostate cancer, it’s important to determine the extent of the disease in order to develop an appropriate treatment plan. Prostate cancer is highly treatable with positive outcomes if it’s caught early. However, if the cancer metastasizes—or spreads to distant parts of the body—the five-year survival rate is about 30 percent.
What’s the difference? Gleason score vs. PSA test
While a Gleason score is one tool to help diagnose prostate cancer, a PSA test is another. But they are very different tests, administered differently and for different reasons.
Grades the aggressiveness of cancer cells in the prostate |
Measures the level of the prostate-specific antigen protein |
Is measured after cancer has been diagnosed |
Helps determine whether someone may have cancer |
Requires a biopsy |
Requires a blood sample |
Men with prostate cancer frequently have elevated PSA levels, though other factors may contribute to high levels, including a urinary tract infection (UTI), or an inflamed or enlarged prostate, while certain medications may lower the PSA level.
Farshid Sadeghi, MD, Urologist and Medical Director of the Genitourinary Cancer Center CTCA Phoenix, recommends that men talk to their doctor about when to get a PSA test and a digital rectal examination to get a more complete and accurate prostate cancer screening.
To screen or not to screen?
The current recommended prostate cancer screening guidelines from the U.S. Preventive Services Task Force (USPSTF), the group that makes evidence-based recommendations about clinical preventive services, is for men between the ages of 55 to 69 to consult their health care providers to determine individual risks and benefits of screening tests.
“The decision to undergo periodic PSA-based screening for prostate cancer should be an individual one,” the USPSTF says. “Many men will experience potential harms of screening, including false-positive results that require additional testing and possible prostate biopsy; over-diagnosis and over-treatment; and treatment complications, such as incontinence and erectile dysfunction.”
Race, age, family history and other diseases or conditions a patient may have should also be considered. According to the American Cancer Society (ACS), men 65 and older account for six in 10 cases of prostate cancer, with 66 the average age at diagnosis. Black men and Caribbean men of African ancestry are at increased risk for developing the disease, and they are often diagnosed younger compared to men of other ethnicities.
The task force does not recommend a PSA test for men older than 70.
For those who opt to undergo prostate cancer screening, the ACS recommends:
- Screening at age 50 if you’re at average risk for prostate cancer and are expected to live at least 10 more years
- Screening at 45 if you’re in a high-risk category, which includes black men and men with a first-degree relative (father or brother) diagnosed with the prostate cancer before age 65
- Screening at 40 if you have more than one first-degree relative diagnosed with prostate cancer at an early age
If you’ve been diagnosed with prostate cancer and want to explore your treatment options, or if you’re interested in a second opinion on your prostate cancer diagnosis and treatment plan, call us or chat online with a member of our team.
