Cancer Grade vs. Cancer Stage – What is the Difference?

Many people assume the terms cancer grade and cancer stage refer to the same thing. But, in actuality, doctors use different imaging exams and diagnostic tests to determine the stage and grade (two different things) of the cancer. While both help doctors understand how serious the disease is and form an effective treatment plan, they, in fact, measure different aspects of the condition. Read on to know the difference between cancer grade and cancer stage, and what they indicate.

What Is a Cancer Grade?

A cancer’s grade indicates how abnormal the cancerous tissues and cells look under a microscope in comparison to healthy cells. Cancer cells that organize and look very similar to healthy tissues and cells are usually low-grade tumors that are less aggressive. These have a better prognosis.

The more abnormal the cells organize themselves and look, the higher the grade of the cancer is. This indicates that the cancer cells are more aggressive. Here’s what the different grades indicate:

Grade 1: The tumor tissues and cells look similar to healthy tissues and cells. These are considered low grade

Grade 2:  The tissues and cells are moderately differentiated and somewhat abnormal. These are called intermediate-grade tumors.

Grade 3: The cancer tissues and cells look very abnormal and are poorly differentiated. This is considered high-grade cancer.

Grade 4: The cancer cells look most abnormal and they typically spread and grow quite fast.

What Is a Cancer Stage?

A cancer stage refers to how large the primary tumor is and how far away the cancerous cells have spread. Here’s what the different stages of cancer indicate:

Stage 0: This refers to abnormal cells that haven’t spread yet and are not considered cancerous yet. This stage is also known as “in-situ”

Stage I to Stage III: Here, the cancer cells have not spread beyond the primary site but have spread to the nearby tissue. The higher the stage, the larger the tumor and the more it has spread

Stage IV: In this stage, the cancer cells have spread to distant areas of the affected individual’s body.