From the Guidelines
The Gleason score is a crucial grading system used to evaluate the aggressiveness of prostate cancer, ranging from 2 to 10, with higher scores indicating more aggressive cancer, as outlined in the 2007 update guideline for the management of clinically localized prostate cancer 1. The 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 from 1 to 5.
- The primary grade is assigned to the most predominant grade present
- The secondary grade is assigned to the second most predominant grade, unless the highest (most aggressive) pattern present is not either the most predominant or second most predominant, in which case it is used as the secondary grade. Scores of 2 to 4 are uncommon, and the majority of detected tumors range from 5 to 10, with scores of 6 or less generally indicating slow-growing cancer with a favorable prognosis.
- A score of 7 suggests intermediate-risk cancer, with 3+4=7 being less aggressive than 4+3=7, as reported in the guideline 1.
- Scores of 8-10 indicate high-risk, aggressive cancer that may spread more rapidly. The Gleason score helps guide treatment decisions, with lower scores often allowing for active surveillance, while higher scores typically require more aggressive interventions like surgery or radiation, as supported by the guideline 1.
- Modern reporting often uses Grade Groups (1-5) alongside the Gleason score, with Grade Group 1 (Gleason 6) having the best prognosis and Grade Group 5 (Gleason 9-10) having the poorest. This scoring system is essential for determining appropriate treatment strategies and predicting outcomes for prostate cancer patients, emphasizing the importance of accurate Gleason score interpretation in clinical practice, as highlighted in the guideline 1.
From the Research
Gleason Score Interpretation
The Gleason score 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 score ranges from 2 to 10, with higher scores indicating more aggressive cancer.
Factors Affecting Gleason Score Interpretation
- Patient knowledge of the Gleason scoring system is generally low, despite being well-educated and health literate 2
- The revised Gleason scores have improved outcomes in all risk groups, with a consistent increased risk in biochemical failure, metastatic disease, and prostate cancer-related death with each successive grade 3
- Patients with Gleason 9-10 disease have significantly worse prostate cancer-related outcomes than other high-risk patients, suggesting the need for more aggressive treatment modalities 4
Clinical Applications of Gleason Score
- The Gleason score, along with PSA, biopsy results, and clinical stage, can be used to identify optimal candidates for prostate-only radiation therapy 5
- A combination of PSA, Gleason score, and digital rectal examination can be used to stage patients with newly diagnosed prostate cancer, eliminating the need for unnecessary staging studies and pelvic lymphadenectomy in some patients 6
Key Findings
- The Gleason score is an important prognostic factor for prostate cancer outcomes 3, 4
- Patient understanding of the Gleason scoring system is crucial for shared treatment decision-making, but is often limited 2
- The revised Gleason scores have improved the accuracy of prostate cancer diagnosis and treatment planning 3