The higher the grade is, the more aggressive the tumor is. Grade 2 (intermediate) nuclei show features between 1 and 3. A grade 3 (high) indicates larger nuclei with marked variation in size and shape. A grade 1 (low) indicates small nuclei with little variation in size and shape. Nuclear grade is assessed on a scale of 1-3.
Each characteristic is given a score of 1 to 3, resulting in a total score ranging from 3 to 9. It is based on a combined score for nuclear grade, mitotic rate, and histologic grade or architectural differentiation. This measure is often reported using some version of the Bloom-Richardson or the Scarff-Bloom-Richardson scale.
