When a person is diagnosed with invasive breast cancer, their pathology report will include the Nottingham score. This scoring system, also called the histologic grade, is a method pathologists use to classify a tumor’s aggressiveness. By examining cancerous tissue from a biopsy under a microscope, specialists assess specific cell features. This evaluation helps predict how quickly the cancer is likely to grow and spread, which informs a patient’s prognosis and guides treatment decisions.
The Three Components of the Score
The Nottingham score is derived from a microscopic examination of three distinct cellular characteristics. The first is tubule formation, which assesses how closely the cancer cells resemble the structure of normal breast tissue. A pathologist evaluates the percentage of the tumor forming these tube-like structures. A score of 1 is given when more than 75% of the tumor forms tubules, while a score of 3 signifies that less than 10% of the tumor is arranged in tubules, reflecting a more disorganized pattern.
A second component is nuclear pleomorphism, which focuses on the appearance of the cancer cell nuclei. The nucleus is the control center of a cell, containing its genetic material. Pathologists look for variations from the norm, a feature known as atypia. A score of 1 is assigned when the nuclei are small and regular, while a score of 3 indicates marked variation in size and shape, suggesting the cells’ genetic programming has been significantly altered.
The final element evaluated is the mitotic count, a direct measure of how rapidly the cancer cells are dividing. Pathologists count the number of cells in the process of mitosis within a specific area of the tumor tissue. A low mitotic count results in a score of 1, meaning few cells are actively dividing and corresponds to a slower-growing tumor. A high count leads to a score of 3, indicating a faster-growing cancer.
Calculating the Final Grade
After assigning a score of 1, 2, or 3 to each of the three components, the pathologist adds them together. This produces a total score ranging from 3 to 9. This cumulative score provides a standardized and comprehensive assessment of the tumor’s biology.
This total score is then translated into a final, overarching grade. This conversion simplifies the combined score into one of three categories, making it easier to apply in a clinical setting.
- A total score of 3, 4, or 5 corresponds to Grade 1 (well-differentiated).
- A total score of 6 or 7 results in a Grade 2 (moderately-differentiated).
- A total score of 8 or 9 is categorized as Grade 3 (poorly-differentiated).
Interpreting the Grade and Prognosis
The final grade provides insight into the cancer’s likely behavior and the patient’s general prognosis. A Grade 1 (well-differentiated) tumor is one whose cells and organization most resemble normal breast tissue. These cancers are slow-growing, less likely to spread, and are associated with a more favorable prognosis.
A Grade 2 (moderately-differentiated) tumor is intermediate, with features between Grade 1 and Grade 3. These cancers have a moderate rate of growth and an intermediate prognosis. Their cells are more abnormal than Grade 1 cells but not as disorganized as Grade 3 tumors.
Grade 3 (poorly-differentiated) tumors are composed of cells that look very different from normal breast cells and grow in a disorganized manner. These cancers are fast-growing and have a higher likelihood of spreading to other parts of the body. A Grade 3 designation is associated with a poorer prognosis and a greater risk of recurrence.
The Role of the Score in Treatment Planning
The Nottingham score is a factor in a patient’s treatment plan, but it is never considered in isolation. It measures the tumor’s biological aggressiveness, which helps tailor the intensity and type of therapy. For instance, a higher grade may suggest a greater benefit from more aggressive systemic treatments.
An oncologist combines the Nottingham grade with other information, including:
- The cancer’s stage, which describes the tumor’s size and whether it has spread to nearby lymph nodes or distant sites.
- The tumor’s hormone receptor status (estrogen receptor and progesterone receptor).
- Its HER2 status.
These markers determine whether the cancer’s growth is fueled by hormones or a specific protein, which can be targeted with specific therapies.
Integrating these data points allows the medical team to create a personalized treatment strategy. A person with a high-grade (Grade 3) tumor, for example, might be recommended chemotherapy. In contrast, someone with a low-grade (Grade 1) tumor might be treated with surgery and hormone-blocking therapy alone.