Breast Cancer Test Results: Tumor Cell Grade

A breast cancer diagnosis is a life-changing event for a woman. Whether it is early and treatable or late stage and incurable, having breast cancer will change the course of a woman’s life. With a strong support group, the right knowledge, and a good medical team, facing breast cancer is easier.

One of the most confusing things about dealing with cancer is the medical information. The terms and numbers found in a pathology report make little sense to lay people without instruction on what they mean. A pathology report is a detailed document that describes and gives the results of all tests performed on a tissue sample. One of the most important parts of that report is the cell grade.

Tumor Cell Grade
A cell grade is a system that is used to classify tumor cells by how they appear under a microscope. The grade gives information about how aggressive a tumor is and how likely the cells are to grow and spread. The grade is based on three different characteristics of the tumor cells: the shape of the nuclei, the rate of mitosis, or cell division, and differentiation, or how different the cells are from healthy ones. To determine the grade, the pathologist examines a tissue sample that was removed in a biopsy. Each of the three characteristics is given a grade of one through three, called the Bloom Richardson scale.

Nuclear Grade
A grade one for nuclear shape reflects nuclei that are small and regularly shaped. Grade three indicates nuclei that are large and whose shapes are irregular and highly variable. Grade two nuclei have properties that are between grades one and three nuclei. They are larger and somewhat irregular. The higher the grade, the more aggressive the tumor is considered to be.

Rate of Mitosis
Mitosis is the process by which cells, both healthy and malignant, grow and divide to produce new cells. The faster the process is occurring, the more rapidly a tumor is growing and the more aggressive the cancer is. The rate is measured by looking at the cells under the microscope and counting how many are actively dividing. The greater the number of dividing cells, the faster the mitosis rate is. A grade one to three is given for mitosis rate, with one indicating slowest rate and three fastest rate.