BREAST CANCER
GRADES
Every breast cancer, independently of its type, is usually graded on the Nottingham Histological Scale. This is a system that distinguishes between more and less aggressive cancers, based on the degree of difference of the cancer cells from the original functional breast cells from which they developed, the rate the cancer cells replicate, i.e. grow into larger masses, and spread to other parts of the body via the blood and lymphatic system (metastasize). Depending on the molecular characteristics of the cells observed under the microscope, the cancer is assigned a score between 3 and 9 reflecting its cellular appearance and abilities to proliferate and metastasize. The higher a cancer's score on the Nottingham Histological Scale, the more fast-growing and aggressive it tends to be.
Based on these scores, cancers are often grouped into three main categories, or grades:
-
Grade 1: Well-differentiated (meaning, still fairly similar to the original functional cells), slow-growing and rarely metastasizing (Score 3-5)
-
Grade 2: Moderately-differentiated (less similar to the original cells, but still somewhat recognizable), faster-growing and occasionally metastasizing (Score 6-7)
-
Grade 3: Poorly-differentiated (pretty different from the original cells, and barely recognizable), very fast-growing and often metastasizing (Score 8-9)
Luminal A type breast cancers tends to be grade 1 (low grade) cancers, while Luminal B type breast cancers are often grade 2 (intermediate grade). HERs-positive and Basal-type (triple negative) breast cancers are frequently grade 3 (high grade).