All of the following statements are TRUE about Gleason score, EXCEPT:
**Core Concept**
The Gleason score is a grading system used to evaluate the prognosis of prostate cancer based on the histological appearance of tumor tissue. It takes into account the differentiation and anaplasia of the tumor cells, with higher scores indicating more aggressive cancer.
**Why the Correct Answer is Right**
The Gleason score ranges from 2 to 10 and is calculated by adding the scores of the two most prevalent histological patterns in the tumor. A higher Gleason score is associated with a worse prognosis. The score is used to stratify patients according to their risk of disease progression and to guide treatment decisions.
**Why Each Wrong Option is Incorrect**
* **Option A:** This statement is true, as the Gleason score is indeed based on the histological appearance of tumor tissue. The score takes into account the differentiation and anaplasia of the tumor cells, with higher scores indicating more aggressive cancer.
* **Option B:** This statement is true, as the Gleason score ranges from 2 to 10 and is calculated by adding the scores of the two most prevalent histological patterns in the tumor.
* **Option C:** This statement is false, as the Gleason score is not a direct measure of tumor size. While larger tumors may have a higher Gleason score, the score itself does not take into account the size of the tumor.
* **Option D:** This statement is true, as the Gleason score is used to stratify patients according to their risk of disease progression and to guide treatment decisions.
**Clinical Pearl / High-Yield Fact**
The Gleason score is a critical prognostic factor in prostate cancer, and a higher score is associated with a worse prognosis. It is essential for clinicians to accurately assign a Gleason score based on histological examination of tumor tissue to guide treatment decisions.
**Correct Answer: C. Larger tumors may have a higher Gleason score, but the score itself does not take into account the size of the tumor.**