The Gleason grading system is used to assign a score that measures how aggressive prostate cancer. The Gleason score is evaluated by looking at tiny samples of prostate tissue taken during a biopsy. In the biopsy, a tiny cores of tissue is taken from the prostate gland and studied under a microscope.
A pathologist studies these samples under a microscope and assigns a score based on how abnormal the cells and tissues appear. This score helps doctors and patients understand the severity of prostate cancer and assists them in deciding on the best course of treatment.
Gleason Score and International Society of Urological Pathology (ISUP) Grade Groups
The new, ISUP prostate grading system expands on the Gleason grading system and provides a more simplified grouping. In the Gleason system, a grade of 2-10 can be assigned, with 6 being the lowest grade that defines cancer. The ISUP grading system includes only 5 grade groups, all describing cancer, and starts with Grade Group 1. Starting the grading system at 1 instead of 6 can reduce the overtreatment of less aggressive disease.
Here is the correspondence between Gleason score and ISUP Grade Group:
- Gleason 3+3 = 6 – Grade Group 1
- Gleason 3+4 = 7 – Grade Group 2
- Gleason 4+3 = 7 – Grade Group 3
- Gleason 4+4, 3+5, 5+3 = 8 – Grade Group 4
- Gleason 4+5, 5+4, 5+5 = 9/10 – Grade Group 5
Read more details about the ISUP Grade Groups here. (refer to Epstein et al 2016 Am J Surg Path)
A Detailed Look into Gleason Score 4+3
A Gleason Score of 4+3 represents a moderately aggressive form of prostate cancer. In this case, the primary or most predominant pattern has a grade of 4, and the secondary pattern has a grade of 3.
The two patterns are added together to obtain the Gleason Score of 7 (4+3). However, it is important to note that a Gleason Score of 7 can also represent Gleason pattern 3+4 disease. The order of the numbers matters because the first number represents the primary or most common pattern, while the second number represents the secondary or second most common pattern.
A Gleason Score of 4+3 is considered more aggressive than a 3+4 score because the primary pattern (grade 4) indicates a higher degree of cancer cell abnormality and disorganization. Generally, a Gleason Score of 7 indicates moderately aggressive prostate cancer, but a 4+3 Gleason score is associated with a higher risk of progression and poorer outcomes compared to a 3+4 score. In fact, the ISUP grading system assigns a different grade to each of these: Gleason score 7=3+4 is Grade Group 2, while Gleason score 7=4+3 is Grade Group 3. As always, it is essential to discuss the Gleason Score and other diagnostic results with your healthcare team. Your caregivers will take into account various factors, such as your age, overall health, and the stage of the cancer, to determine the most appropriate treatment plan for your specific situation.
Next Steps After a Gleason Score of 4+3
If a prostate biopsy reveals cancer cells that appear almost normal and lead to a Gleason Score of 2, it represents a very low-risk, non-aggressive form of prostate cancer. After a Gleason Score of 2, the next steps would involve discussing the results with your healthcare team. Treatment options could include active surveillance (monitoring the cancer closely with regular follow-ups) or localized treatments.
Blog posts from Profound Medical are for general information only. The content should not be considered medical advice. If you are in need of professional medical advice or assistance, please reach out to your local doctor or clinic.
Jul 19, 2023 | TULSA Procedure