From the Guidelines
The Gleason score is a grading system used to evaluate the aggressiveness of prostate cancer, ranging from 2 to 10, with higher scores indicating more aggressive cancer, as determined by adding the grades of the two most common histologic patterns seen in each biopsy core, with each pattern scored from 1 to 5, as described in the study published in the American Family Physician in 2011 1. The Gleason score is calculated by adding two numbers: the primary grade (representing the most common tumor pattern) and the secondary grade (representing the second most common pattern), each rated on a scale of 1 to 5. Some key points to consider when evaluating the Gleason score include:
- The most common grade is 6, whereas grades 2 to 5 are uncommon, as noted in the study 1.
- Grade 6 identifies a tumor with well-differentiated histology; grade 7 has intermediate differentiation; and grades 8 to 10 are the most poorly differentiated and have the worst prognosis, as reported in the American Family Physician study 1.
- A grade 7 cancer is more aggressive if its scoring is 4+3 instead of 3+4, highlighting the importance of considering the specific grade combination when evaluating the Gleason score, as discussed in the study 1. The Gleason score helps doctors determine appropriate treatment options and predict outcomes, with lower scores often warranting less aggressive treatments and higher scores requiring more aggressive interventions, such as surgery, radiation, or hormone therapy, as is typical in modern practice 1.
From the Research
Definition and Purpose of Gleason Score
- The Gleason scoring system is a key component of a prostate cancer diagnosis, indicating disease aggressiveness and serving as a risk communication tool for shared treatment decision-making 2.
- The system is used to evaluate the prognosis of patients with prostate cancer, with higher scores indicating more aggressive disease.
Calculation and Interpretation of Gleason Score
- The Gleason score is calculated by adding the grades of the two most prevalent patterns of tumor growth, ranging from 2 to 10 3.
- A higher Gleason score is associated with a worse prognosis, with scores of 10 indicating the most aggressive form of clinically localized prostate adenocarcinoma.
Clinical Implications of Gleason Score
- Patients with a high Gleason score are at increased risk of disease progression and may require more aggressive treatment, such as radical prostatectomy or external beam radiation therapy 3, 4.
- The Gleason score can also be used to identify patients who may be candidates for active surveillance, a treatment approach that involves monitoring the disease with regular check-ups and biopsies rather than immediate treatment 5, 4.
Limitations and Challenges of Gleason Score
- The Gleason scoring system can be complex and difficult to communicate to patients, which can undermine well-informed and high-quality shared treatment decision-making 2.
- There is also a risk of Gleason score upgrading, where the score is higher than initially thought, which can impact treatment decisions and outcomes 5.
Prognostic Value of Gleason Score
- The Gleason score has been shown to be a significant predictor of biochemical progression-free survival, cause-specific survival, and overall survival in patients with prostate cancer 3, 6.
- The primary pattern of the Gleason score can also provide prognostic information, with patients having a primary pattern of 3 tend to have a better prognosis than those with a primary pattern of 4 6.