A tumor grade is important in determining the potential severity of the disease. However, a more comprehensive descriptor is needed to determine cancer progression. This is where cancer staging comes in. A cancer stage not only factors in the tumor grade, but also the tumor size, position, spread, number of tumors, cell type, and involvement of neighboring lymph nodes. This information is gathered by a wide range of clinical tests including CT scans, MRI, ultrasound as well as biopsies.
Right: Breast cancer tissue