Breast cancer staging and grading

When you receive a breast cancer diagnosis; your team will discuss two important measurements: the stage and the grade. These tell us very different things about your individual cancer, and together they help shape the right plan for you. Staging describes how far the cancer has spread in the body and beyond the original site. We use the TNM system, which stands for: Tumour, Node, and Metastasis. T describes the tumour size; N tells us about lymph nodes; and M shows whether the cancer has spread. There are several T categories: T1 means the tumour is two centimetres or smaller; and T2 is between two and five centimetres in size. T3 is larger than five centimetres; while T4 means the cancer has invaded the chest wall, or the overlying skin of the breast. The N category tells us whether the cancer has reached nearby lymph nodes in the armpit; with higher numbers showing more involvement. Finally, the M category shows whether the cancer has spread to distant organs such as the lungs; liver; bones; or brain. Combining the T, N, and M scores gives us the overall stage, from 0 to IV. Stage 0 means non-invasive cancer like DCIS or LCIS; while Stage I is a small invasive tumour. Stages II and III describe larger tumours or those involving lymph nodes; and Stage IV means the cancer has spread. While the Stage tells us where the cancer is; the Grade tells us how the cells behave. Grade and stage are independent of each other; but both contribute to your individual prognosis. A pathologist examines the biopsy, and gives the cancer a grade from one to three, based on how closely the cells resemble normal breast tissue. Lower-grade cells look more like healthy cells, and tend to grow more slowly than higher-grade ones. Grade 1 means well-differentiated cells, which look most like normal tissue, and tend to grow slowly. Grade 2 cells are moderately differentiated; with some abnormal features but a moderate growth rate. Grade 3 means poorly differentiated cells that look very abnormal, and tend to grow more quickly. Understanding your stage and grade allows us to estimate your prognosis, and plan your treatment. However, other factors also shape your treatment plan, including hormone receptor status; and HER2 status. Together, all of these factors guide the most effective treatment approach for your individual situation. Thank you for watching. If anything about your stage or grade is unclear; please contact my team and we'll a arrange a time to talk it through with you.