tumor grade
A histologic assessment of how abnormal cancer cells look under microscopy and how quickly the tumor is likely to grow.
Full Definition
Tumor grade is a pathologic assessment that describes how much the cancer cells differ from normal breast cells and indicates how aggressive the cancer is likely to be. Breast cancer grading typically uses the Nottingham grading system (also called Scarff-Bloom-Richardson system), which evaluates three features: tubule formation, nuclear pleomorphism, and mitotic rate. Grades are assigned as Grade 1 (low grade, well-differentiated), Grade 2 (intermediate grade, moderately differentiated), or Grade 3 (high grade, poorly differentiated). Higher grades generally indicate more aggressive tumors with higher risk of recurrence.
Usage
Usage note: Distinguish from tumor stage, which describes extent of disease spread.
In Context
- "The tumor grade was 2 (6/9) based on moderate nuclear pleomorphism and mitotic activity." — Pathology report
- "High tumor grade was identified as an adverse prognostic factor in the risk assessment." — Multidisciplinary team discussion