What Does Your Gleason Score Mean?
A prostate biopsy is the key test a pathologist (a medical doctor who works in a lab) uses to find out if a man has prostate cancer. But cancer isn’t the only thing that the pathologist is looking for when they look at the biopsy tissue under a microscope. In addition to looking for the presence of prostate cancer, a pathologist looks for details in the tumor to find out how aggressive the cancer is.
Pathologists use a scale from Grade 3 to 5 to describe how aggressive the prostate cancer cells look after a prostate biopsy. This is called the tumor “grade.” Because a biopsy sample may have different areas with different grades of prostate cancer, pathologists give two scores. These scores represent the most common and second most common grades for each area of the biopsy tissue with cancer. They are added together to form the Gleason score. The Gleason score ranges from 6 to 10. More recently, these grades have been recategorized into “Gleason Grade Groups” which range from 1 to 5.
The Gleason score (or Gleason Grade Group) is combined with the PSA test result and the tumor stage to find out the prostate cancer risk group. More details about this are in the risk stratification content on this site. However, the tumor grade (Gleason score/Grade Group) is important to know how prostate cancer will behave. Findings on rectal exams, PSA blood tests, and imaging tests are also important. In addition to this, whether or not cancer has spread outside of the prostate will affect treatment options.
What does it mean to have Gleason score 6 prostate cancer?
Gleason score 6, or Grade Group 1, prostate cancer is the least aggressive kind of prostate cancer. In fact, in recent years, there has been debate in the medical community as to whether it should even be called prostate cancer. This is because it most often does not grow into nearby organs and spread throughout the body.
The most important thing for men diagnosed with Gleason 6 prostate cancer to know is if the cancer grade is true or not. A prostate biopsy is just a sampling of the prostate and the tumors within it. While the hope is that the samples the pathologist studies represent the whole prostate and/or cancer, they may not.
Studies show that of men whose prostates were surgically removed some with Gleason 6 cancer (based on their biopsy) will be found to have Gleason 7 cancer when the whole prostate is examined after removal. Interestingly, the reverse is also true. Some men who seem to have Gleason 7 disease on biopsy are found to have Gleason 6 disease when the prostate is removed.
In the last few years, many urologists have adopted new technologies to better diagnose prostate cancer. The most important of these is magnetic resonance imaging (MRI). Using MRI scans allows targeted biopsies at areas that appear abnormal on the scan. This increases the chances of finding the true cancer characteristics.
What are the treatment options for Gleason score 6 Prostate Cancer?
Most men with Gleason 6 cancer will be classified as having low-risk cancer. However, a higher PSA (greater than 10 ng/mL) or more advanced cancer found in a rectal exam may change this. For most men with Gleason 6 prostate cancer, no further testing is required before making treatment decisions.
The American Society for Clinical Oncology (ASCO) recommends active surveillance as the “best available care option” for patients with very-low risk prostate cancer. It is also the “preferable care option” for most patients with low-risk prostate cancer. These are the groups into which most men with Gleason 6 prostate cancer fit.
Active surveillance is based on the fact that only a small number of men with low-risk prostate cancer will have disease that causes problems by growing to cause urinary issues or spreading outside the prostate (metastasizing).
Prostate cancer treatments, including surgery and radiotherapy, can have risks and complications. These include urine leakage (incontinence), impotence (erectile dysfunction), trouble urinating (peeing), and bowel problems. As a result, avoiding (or putting off) treatment may be a big benefit to a patient’s quality of life as long as it doesn’t lead to worse cancer outcomes.
Recent studies have shown that active surveillance is being used more and more in the United States. However, it is used much more often in other countries such as Canada, Sweden, the United Kingdom, and others.
Men who choose active surveillance will be checked with routine PSA tests (usually every 6 months), an MRI (if not already done), and a confirmatory biopsy. This confirmatory biopsy (done after the “diagnostic biopsy” that first diagnosed prostate cancer) is important to make sure that more aggressive cancer wasn’t missed on the first biopsy. You can learn more about this in the article on active surveillance.
Active surveillance is the preferred approach for most men with Gleason 6 prostate cancer. But some men may choose treatment after talking with their family and doctors. In this case, surgery (radical prostatectomy) or radiotherapy may be used.
Surgery typically is performed using the da Vinci robotic platform. Radiotherapy may be given using either external beam radiotherapy or brachytherapy. For men with Gleason 6 prostate cancer, hormone therapy (ADT) typically is not required at the time of radiotherapy.
What does it mean to have Gleason Score 7 prostate cancer?
Gleason score 7 prostate cancer includes both Gleason score 3 + 4 (Grade Group 2) and Gleason score 4 + 3 (Grade Group 3) prostate cancer. In general, both of these are called intermediate-risk prostate cancer. However, a man with Gleason 7 prostate cancer could have high-risk disease if he had a high PSA (over 20) or more advanced tumor stage.
Comparing these two, for men with Gleason score 3 + 4 prostate cancer, most of the tumor cells are the less aggressive Gleason pattern 3 while a smaller amount is the more aggressive pattern 4. So, compared to Gleason 4+3 disease, the cancer is likely to grow more slowly. Unless the PSA is greater than 10 ng/mL, most doctors will not order more imaging studies for patients with Gleason 3 + 4 disease to see if the prostate cancer has spread. Because of the more aggressive cells in Gleason score 4 + 3 prostate cancer, most doctors will order more staging imaging studies (such as CT, MRI, or PSMA PET/CT) for these men. If the PSA level is less than 20 ng/mL and there is no obvious (or low risk of) spread outside of the prostate gland, the following are treatment options for Gleason Score 7 prostate cancer:
What are the treatment options for Gleason Score 7 prostate cancer?
Gleason Score 3 + 4 Prostate Cancer
Patients over 70 years of age or unhealthy patients with low volume (about 1-2 cores positive on prostate biopsy) Gleason 3 + 4 disease may be candidates for active surveillance. Also, men with Gleason score 3 + 4 disease that have MRI visible index lesions may be candidates for focal therapy, such as high-intensity focused ultrasound (HIFU) treatment.
However, for most men with Gleason 3+4 disease, and particularly for younger and healthier men, traditional treatment options are preferred. These include radiotherapy, which may be external beam radiotherapy or brachytherapy, or surgery.
For men who choose radiotherapy, androgen deprivation therapy (ADT) during or after treatment typically is not necessary for Gleason score 3 + 4 prostate cancer. Men may also choose radical prostatectomy (surgical removal of the prostate).
Gleason Score 4 +3 Prostate Cancer
Most men with Gleason score 4 + 3 disease will require some form of treatment. They will not be candidates for active surveillance. Also, very few of these men will be candidates for focal therapy secondary to the risk of under-treatment of disease. Because of this, most men with Gleason 4 + 3 disease will choose radiotherapy options (often with about 6 months of ADT) or radical prostatectomy (surgery).
What does it mean to have Gleason Score ≥8 prostate cancer? (A Gleason Score of 8 or higher)
Gleason score ≥8 prostate cancer means that you have high-risk prostate cancer. This includes any of the following on prostate biopsy:
- Gleason score 4 + 4 (Grade Group 4)
- Gleason score 4 + 5 (Grade Group 5)
- Gleason score 5 + 4 (Grade Group 5)
- Gleason score 5 + 5 (Grade Group 5)
Based on the Gleason score (or Grade Group) alone, regardless of PSA or clinical stage, all of these combinations are enough to make a man’s prostate cancer high risk.
For Gleason score 4 + 4 prostate cancer, all of the cells are abnormal and are likely to be aggressive.
For men with Gleason 4 + 5, Gleason 5 + 4, or Gleason 5 + 5, the cells look very abnormal and are quite likely to be very aggressive.
What are the treatment options for Gleason Score ≥8 prostate cancer?
With Gleason ≥8 prostate cancer, this is enough information to show that the prostate cancer is high risk. Given the high-risk prostate cancer, staging studies are needed to help decide on treatment options. These additional staging imaging studies typically include bone scan + CT/MRI, or PSMA PET/CT. Based on the NCCN guidelines, a PSMA/CT scan is recommended and does not require a negative bone scan + CT/MRI.
For most men, Gleason ≥8 prostate cancer is aggressive and requires treatment. Unless men have other severe health problems with very poor life expectancy, active surveillance or watchful waiting are not recommended. Also, men with Gleason ≥8 prostate cancer are not candidates for focal therapy due to the risk of under-treatment of disease.
For men with Gleason ≥8 prostate cancer and negative staging studies (historically a CT or MRI and bone scan; more recently a PSMA PET/CT scan), the two main options for treatment are radiotherapy or radical prostatectomy (surgery). Those who choose radiotherapy should be given ADT during and after treatment for 18-24 months. This is based on trials that show an improvement in survival when combining radiotherapy and ADT.
Men with Gleason ≥8 prostate cancer may also opt for radical prostatectomy (surgical removal of the prostate). For the most part, these will be younger men with Gleason 4 + 4 disease who may still benefit from surgery.
In all cases of radical prostatectomy for Gleason ≥8 prostate cancer, pelvic lymph node testing should be done to help stage the prostate cancer. It is important to know that there is about a 30%-50% chance that men with Gleason ≥8 prostate cancer who choose primary robotic prostatectomy may need salvage radiotherapy after surgery. This most often is needed in cases of persistent PSA right after surgery or increasing PSA in the months after surgery.
Understanding the details of your prostate cancer and how they affect the way your cancer might behave is an important step toward choosing the right treatment for you. As you move forward, look for articles about other tests you may need and details on treatment options before you decide on treatment.