Cancer Grading vs. Staging: What’s the Difference?

When you or a loved one is diagnosed with cancer, medical terminology can feel overwhelming. The distinction between cancer grade and stage is one of the most important phrases you will come across. Despite having a similar sound, they explain completely different parts of the illness. Knowing this difference is essential to understanding your diagnosis and prognosis.

What is Cancer Grading?

The cancer cells themselves are the main focus of cancer grading. To assess the tumour's aggressiveness, a pathologist looks at the cells under a microscope. Cell differentiation serves as a means of evaluating this.

• Low-grade, well-differentiated cancer cells resemble healthy, normal cells in certain ways. They usually spread and expand slowly.
• High Grade (poorly differentiated): The cells are wildly disorganised and aberrant. Because they develop and spread faster, these tumors are often more aggressive.

What is Cancer Staging?

Cancer staging describes the size of the original tumour and the extent of its spread within the body. The most common system is the TNM system (Tumour, Node, Metastasis).

• T: The original tumour's size.
• N: Whether adjacent lymph nodes have been affected by cancer.
• M: Has it metastasised, or spread to other organs?

Usually, a stage is represented by a number between 0 and IV. While Stage IV indicates that the cancer has spread to other places in the body, Stage 0 indicates that the cancer is contained. The questions of where and how much cancer there is are addressed by staging. We have done a deeper dive into the TNM Staging process, in “Demystifying the TNM Staging System: A Patient’s Guide”. 

How They Work Together for Treatment

Together, grade and stage provide a comprehensive picture and influence treatment decisions. Even if detected early, a high-grade malignancy may require more intensive therapy. On the other hand, systemic therapy would still be necessary for a low-grade malignancy that has spread (a higher stage).

Examples:

• Breast Cancer: Chemotherapy may be necessary to prevent recurrence of a tiny, high-grade, early-stage (I) tumor.
• Prostate Cancer: When choosing between active surveillance and treatment for prostate cancer, the Gleason score is a sort of grade that is essential. The Gleason score is a system used to grade the aggressiveness of prostate cancer. It is determined by examining a prostate biopsy and seeing how much the cancer cells differ from healthy tissue. A higher score means the cancer is more aggressive and likely to spread.

How to Read Your Pathology Report

• Diagnosis: Identifies the cancer type.
• Tumor Grade: Usually expressed as a number (Grades 1, 2, and 3) or as a phrase such as "poorly differentiated."
• TNM Staging: Will list the T, N, and M categories and the stage group as a whole.

Talk to your oncologist about your report at all times. To suggest the best course of action for you, they will take into account a number of variables, including your grade, stage, general health, and others. You can take an active role in your care if you understand these concepts.