Final answer:
The grade of breast cancer is a classification of how cancer cells look compared to healthy cells, which can range from well-differentiated (low grade) to poorly differentiated (high grade). Cancer staging involves assessment of tumor size and spread, with stage IV indicating metastasis to distant body parts.
Step-by-step explanation:
The grade of breast cancer refers to how much cancer cells differ from healthy cells under a microscope. This aspect is part of cancer staging, which is a way of classifying cancer based on such factors as how large a tumor is and the extent to which the cancer has spread. Determining the grade and stage of cancer is important for deciding on the most effective treatment and understanding the prognosis.
There are different grades of cancer; they are typically categorized as follows:
- Well-differentiated (low grade) - Cancer cells look more like normal cells and tend to grow slowly.
- Moderately differentiated (intermediate grade) - Cancer cells look somewhat different from normal cells and grow at a moderate rate.
- Poorly differentiated (high grade) - Cancer cells look very different from normal cells and tend to grow and spread more quickly.
For example, a definitive diagnosis of cancer such as carcinoma (which includes breast cancer), requires a biopsy to classify and name the cancer by the type of tissue where cancer began.
If breast cancer metastasized to a patient's brain, the cancer would likely be classified as an advanced stage, specifically stage IV, which signifies that cancer has spread to distant parts of the body.