What is the primary use of Gleason scores in oncology?

The primary use of Gleason scores in oncology is to indicate prognosis in prostate cancer. The Gleason scoring system is a histological grading system that evaluates the architectural patterns of prostate cancer cells observed in biopsy specimens. It helps in determining the aggressiveness of the cancer.

The scores are derived by assigning a grade to the two most predominant patterns of cancer cells, with each pattern given a score from 1 to 5. The two scores are then added together to give a Gleason score ranging from 2 to 10. Higher scores indicate a more aggressive tumor that is likely to grow quickly and spread, thus correlating with a poorer prognosis for the patient. This information is crucial for treatment decision-making, as it helps oncologists determine the appropriate course of action based on the expected behavior of the cancer.

Other choices relate to different aspects of oncology but do not accurately describe the specific function of the Gleason score. For instance, measuring tumor size is essential in staging but is not an application of the Gleason score. Similarly, staging leukemia involves other systems and classifications, and evaluating lymph node involvement typically relies on imaging and physical examination rather than histological grading.