Gleason Score - Purpose, Procedure, Results Interpretation, Normal Values and more

The Gleason Score is a crucial diagnostic tool used by doctors to assess the aggressiveness of prostate cancer. This scoring system is based on the appearance of cancer cells under a microscope and is one of the primary factors in determining the course of treatment for patients diagnosed with prostate cancer. The Gleason Score helps to classify the severity of the cancer, providing essential information about how likely the cancer is to grow and spread. Understanding the Gleason Score is vital for patients, as it directly influences treatment decisions and outcomes.

What is the Gleason Score?

The Gleason Score is a grading system used to evaluate the aggressiveness of prostate cancer by examining the cancerous cells’ patterns under a microscope. The score helps doctors predict how quickly the cancer may grow and spread and serves as a guide for determining the most appropriate treatment plan.

The Gleason Score is based on the Gleason Grading System, which classifies prostate cancer into grades based on the organization of the cancer cells. The grade of prostate cancer is determined by the appearance of the cells in the biopsy sample. The more abnormal the cells appear, the higher the grade, which indicates a more aggressive cancer.

The Gleason Score is assigned as a sum of two values:

• Primary Gleason Grade: This is the most common pattern found in the biopsy sample, representing the largest portion of cancerous tissue.
• Secondary Gleason Grade: This represents the second most common pattern of cancer cells found in the sample.

Both grades are scored on a scale from 1 to 5, with 1 being the least aggressive and 5 being the most aggressive. The final Gleason Score is the sum of these two grades, typically ranging from 2 to 10. The higher the score, the more aggressive and likely to spread the cancer is.

How is the Gleason Score Determined?

The Gleason Score is determined by a pathologist who examines a prostate biopsy sample under a microscope. Prostate biopsies are usually performed when there are concerns about elevated prostate-specific antigen (PSA) levels or abnormal findings during a digital rectal exam (DRE). The biopsy involves removing small tissue samples from different parts of the prostate for analysis.

The pathologist looks at the cancer cells’ patterns, noting how similar or different they are compared to normal prostate tissue. These patterns are assigned a grade from 1 to 5, where:

• Grade 1: Cancer cells closely resemble normal prostate cells, indicating a less aggressive form of cancer.
• Grade 2: Cancer cells are slightly more abnormal but still resemble normal cells.
• Grade 3: Cancer cells appear irregular and lose their normal structure.
• Grade 4: Cancer cells have little resemblance to normal cells and are more abnormal.
• Grade 5: Cancer cells are very irregular and poorly differentiated, indicating a highly aggressive form of cancer.

After identifying the primary and secondary patterns, the pathologist adds the two grades together to give the final Gleason Score. For example, a Gleason Score of 7 could be the result of a primary grade of 4 and a secondary grade of 3.

Interpreting the Gleason Score

The Gleason Score provides important information about the nature of the prostate cancer, helping doctors decide on the best treatment options. Understanding how to interpret the score is key for patients and doctors alike.

• Gleason Score 6 or lower: Considered low-grade prostate cancer. This type of cancer tends to grow slowly and is less likely to spread to other parts of the body. Treatment may include active surveillance, where the cancer is monitored over time without immediate intervention.
• Gleason Score 7: Considered intermediate-grade cancer. This type of cancer has a moderate likelihood of growing and spreading, and treatment options may include surgery, radiation therapy, or active surveillance.
• Gleason Score 8-10: Considered high-grade cancer. These cancers are more aggressive and likely to grow quickly and spread to other parts of the body. Treatment options typically include surgery, radiation therapy, and sometimes chemotherapy, depending on the extent of the cancer.

Normal Range for the Gleason Score

The normal range for the Gleason Score is between 2 and 10. The score is determined by adding the two most common patterns seen in the biopsy sample. A score of 2 (which is rare) indicates well-differentiated cells that resemble normal prostate tissue, while a score of 10 indicates poorly differentiated and highly aggressive cancer cells.

Most prostate cancers fall into the intermediate or high-grade categories, with a Gleason Score of 6-7 being most common among men diagnosed with prostate cancer. Scores above 7 generally indicate a higher likelihood of the cancer spreading or being resistant to treatment.

Uses of the Gleason Score

The Gleason Score serves several important functions in the diagnosis, treatment, and prognosis of prostate cancer:

• Determining Cancer Aggressiveness: The Gleason Score helps to determine how aggressive the cancer is, which informs decisions about treatment options. A higher Gleason Score typically indicates a more aggressive form of cancer that may require more intensive treatment.
• Guiding Treatment Decisions: The Gleason Score plays a significant role in choosing the most appropriate treatment plan. Low-grade cancers may not require immediate intervention, while high-grade cancers may necessitate more aggressive treatment, such as surgery, radiation, or chemotherapy.
• Predicting Prognosis: The Gleason Score is a predictor of how well a patient may respond to treatment and what the long-term outlook may be. Higher scores are associated with a higher risk of recurrence or metastasis.
• Risk Stratification: The Gleason Score, in combination with other tests such as PSA levels and imaging studies, helps classify prostate cancer into different risk categories (low, intermediate, high) to guide management and follow-up care.

How to Prepare for the Gleason Score Test

There is no specific preparation required for the Gleason Score test itself, as it is determined from the results of a prostate biopsy. However, patients may need to prepare for the biopsy procedure, which may involve the following:

• Medications: Inform your doctor about any medications you are currently taking, especially blood thinners like aspirin or warfarin, as they may need to be temporarily stopped before the biopsy to reduce the risk of bleeding.
• Antibiotics: You may be prescribed antibiotics before the biopsy to prevent infection.
• Fast: Some doctors may recommend fasting for a few hours before the procedure.
• Post-Biopsy Care: After the biopsy, you may experience mild discomfort, such as bruising, bleeding, or soreness in the rectal area. Your doctor will provide specific aftercare instructions, including what to watch for signs of infection.

Factors That Can Affect the Gleason Score

Several factors can influence the accuracy and interpretation of the Gleason Score:

• Biopsy Sample Size: A prostate biopsy involves taking several tissue samples from different areas of the prostate. If the biopsy does not include the most aggressive parts of the cancer, the Gleason Score may not accurately reflect the overall aggressiveness of the tumor.
• Interobserver Variability: The Gleason Score is determined by a pathologist, and different pathologists may interpret the same sample slightly differently. However, standardized grading systems have helped minimize this variability.
• Tumor Heterogeneity: Prostate cancers can be heterogeneous, meaning that different areas of the tumor may have different Gleason Scores. In some cases, the highest grade found in the biopsy is used to determine the Gleason Score.

10 Frequently Asked Questions About the Gleason Score

1. What does the Gleason Score indicate about prostate cancer?

The Gleason Score is a grading system that evaluates the aggressiveness of prostate cancer. A higher score indicates more aggressive cancer, while a lower score indicates slower-growing cancer. This score helps doctors determine the appropriate treatment and predict the likelihood of cancer spreading.

2. How is the Gleason Score determined?

The Gleason Score is determined by a pathologist who examines the prostate biopsy sample under a microscope. The most common patterns of cancer cells are assigned grades from 1 to 5, and the two most common patterns are added together to form the final score.

3. What is the significance of a Gleason Score of 7?

A Gleason Score of 7 is considered an intermediate-grade cancer. It indicates that the cancer is moderately aggressive, with a higher likelihood of growing and spreading than low-grade cancers. Treatment options may include surgery, radiation therapy, or active surveillance.

4. Is a Gleason Score of 10 a terminal diagnosis?

A Gleason Score of 10 indicates highly aggressive cancer, but it is not necessarily terminal. While high-grade cancers are more likely to spread and be resistant to treatment, many patients with a Gleason Score of 10 respond to aggressive treatments like surgery, radiation, or chemotherapy.

5. Can the Gleason Score change over time?

The Gleason Score is determined based on the initial biopsy. However, the cancer’s aggressiveness can change over time, and additional biopsies or imaging studies may be needed to reassess the Gleason Score if the cancer progresses or recurs.

6. What does a Gleason Score of 6 mean?

A Gleason Score of 6 indicates low-grade cancer. This type of cancer typically grows slowly and may not require immediate treatment. Active surveillance is often recommended, where the cancer is monitored over time without aggressive intervention.

7. Can a high Gleason Score affect my prognosis?

Yes, a higher Gleason Score generally indicates a more aggressive cancer that is more likely to spread and may have a poorer prognosis. However, treatment options such as surgery and radiation can help manage high-grade prostate cancer and improve survival rates.

8. What treatments are recommended for a high Gleason Score?

For high Gleason Scores (8-10), aggressive treatments are usually recommended. These can include surgery (prostatectomy), radiation therapy, and sometimes chemotherapy, depending on the extent of the cancer and its spread.

9. How accurate is the Gleason Score?

The Gleason Score is highly accurate in predicting the aggressiveness of prostate cancer, but its accuracy can depend on the biopsy sample size and the expertise of the pathologist. Other factors, such as PSA levels and imaging studies, are also considered when determining treatment.

10. How often should I be tested for Gleason Score if I have prostate cancer?

The frequency of testing depends on your Gleason Score, treatment plan, and how your cancer is being managed. Patients with low-grade cancer may undergo less frequent monitoring, while those with higher scores may require more frequent follow-up to assess cancer progression.

Conclusion

The Gleason Score is an essential tool for assessing the aggressiveness of prostate cancer, guiding treatment decisions, and predicting the patient’s prognosis. By examining the patterns of cancer cells under a microscope, the Gleason Score helps doctors determine how likely the cancer is to grow and spread. Whether you have a low or high Gleason Score, understanding what it means is crucial for making informed decisions about your treatment and care.

If you have been diagnosed with prostate cancer, it’s important to discuss the Gleason Score with your healthcare provider to understand the severity of your condition and the best course of action for treatment. With early detection and appropriate treatment, many men with prostate cancer are able to manage the condition effectively and maintain a good quality of life.