Understanding Your Cancer Diagnosis: Stage, Grade and Biomarkers Explained

Receiving a cancer diagnosis can feel overwhelming. Medical reports often contain unfamiliar terms such as stage, grade, biomarkers, mutations, receptors, and molecular testing. Understanding what these terms mean can help you have more informed conversations with your oncology team and better understand why a particular treatment is being recommended.

What does the stage of cancer mean?

The stage describes how extensive a cancer is in the body. Depending on the type of cancer, doctors consider factors such as the size and location of the primary tumour, whether nearby lymph nodes are involved, and whether the cancer has spread to other parts of the body.

For many solid cancers, doctors use the TNM system:

• T (Tumour): the size and extent of the primary tumour.

• N (Nodes): whether nearby lymph nodes contain cancer.

• M (Metastasis): whether the cancer has spread to distant parts of the body.

These findings may then be combined into an overall stage, commonly ranging from Stage I to Stage IV, although staging systems differ between cancer types.

In general, earlier stages represent more localized disease, while Stage IV usually indicates that the cancer has spread to distant organs or tissues.

Importantly, stage alone does not tell the whole story. Two people with the same cancer type and stage may have different tumour biology, general health, treatment options and responses to treatment.

What does tumour grade mean?

Grade and stage are not the same thing.

While stage describes where the cancer is and how far it has spread, grade describes how the cancer cells look under the microscope.

A pathologist examines tumour tissue obtained from a biopsy or surgery and evaluates how different the cancer cells appear from normal cells.

In many cancers:

• Lower-grade tumours tend to look more like normal cells and may grow more slowly.

• Higher-grade tumours tend to look more abnormal and may behave more aggressively.

However, grading systems differ between cancer types. Your oncologist and pathologist interpret the grade in the context of your particular cancer.

What are cancer biomarkers?

Modern oncology increasingly looks beyond where a cancer started.

Biomarkers are measurable biological characteristics that can provide information about a cancer. They may include particular proteins, receptors, gene alterations or other molecular features.

Depending on the cancer type, biomarker testing may help doctors understand the biology of the tumour, estimate prognosis, select particular treatments, or monitor the disease.

Examples include HER2 and hormone receptors in breast cancer; EGFR, ALK, ROS1 and other molecular alterations in certain lung cancers; and RAS or BRAF alterations in some colorectal cancers.

Not every biomarker is relevant to every cancer, and finding a molecular alteration does not automatically mean that a targeted treatment is available or appropriate.

What is molecular or genomic testing?

Molecular testing examines specific characteristics of cancer cells, often including alterations in their DNA or proteins.

Testing may involve looking for a single biomarker or using a broader panel, such as next-generation sequencing (NGS), to examine multiple genes simultaneously.

This approach is an important part of precision oncology, where treatment decisions may incorporate the molecular characteristics of an individual’s tumour in addition to the cancer type and stage.

Testing is commonly performed on tumour tissue. In selected situations, tumour-derived material circulating in the blood can also be examined through a liquid biopsy.

The appropriate test depends on the cancer type, stage, available tumour tissue, previous treatments and the clinical question being addressed.

Putting the information together

Cancer treatment decisions are rarely based on one result alone.

Your oncology team may consider:

Cancer type + stage + grade + biomarkers + your overall health + previous treatments + your individual circumstances and preferences

Together, these factors help your oncology team develop an individualized treatment strategy.

This is why two people who appear to have the same type of cancer may receive different treatment recommendations.

Questions you may want to ask your oncologist

Consider asking:

• What is the exact type and stage of my cancer?

• What is the tumour grade, and what does it mean in my case?

• Has my tumour been tested for relevant biomarkers?

• Would molecular or genomic testing be useful for my cancer?

• Could any of my results affect my treatment options?

• Are targeted therapy or immunotherapy relevant to my cancer?

• Are there clinical trials that may be appropriate for me?

  
  

Understanding your diagnosis does not mean that you need to become an oncology expert. The goal is to help you participate in discussions about your care and understand the reasoning behind your treatment plan.

About the Author

Dr. Sara Fanijavadi, MD, MSc

Specialist in Clinical Oncology | Clinical Oncologist & Researcher

SF Medic Oncology Hub – Clinical Oncology & Research, Madrid, Spain

Medical Disclaimer

This article is intended for general educational and informational purposes only. It does not replace individualized medical advice, diagnosis, or treatment. Cancer diagnosis and treatment decisions should always be discussed with your treating oncology team.

References and Further Reading

1. National Cancer Institute (NCI). Cancer Staging.

2. National Cancer Institute (NCI). Tumor Grade.

3. National Cancer Institute (NCI). Tumor Markers.

4. American Cancer Society. Biomarker and Tumor Marker Tests.

5. European Society for Medical Oncology (ESMO). Patient Guides and Personalised Cancer Medicine.