Stages of Cancer (Explained Clearly)

Cancer stages describe how far the cancer has grown or spread in the body.
Most cancers are staged using the numbers 0 to IV (0–4).

 Stage 0 – Carcinoma in Situ (CIS)

• Cancer is only in the layer of cells where it started.

• It has not invaded deeper tissues.

• Often highly treatable.

 Stage I – Early-Stage Cancer

• Tumor is small.

• Cancer is still localized (has not spread to lymph nodes).

• High chance of successful treatment.

 Stage II – Localized but Larger

• Tumor is larger than in stage I.

• May have grown into nearby tissues.

• Usually has not spread to lymph nodes (or only a few).

 Stage III – Regional Spread

• Tumor may be large.

• Cancer has spread to nearby lymph nodes or tissues.

• More advanced but still potentially treatable.

 Stage IV – Metastatic Cancer

• Cancer has spread to distant organs (lungs, liver, bones, brain, etc.).

• Most advanced stage.

• Treatment focuses on control and improving quality of life.

TNM System (How Doctors Determine the Stage)

Doctors often use the TNM system to define cancer stage:

• T (Tumor) – Size and extent of the main tumor

• N (Nodes) – Whether cancer has spread to lymph nodes

• M (Metastasis) – Whether cancer has spread to distant organs

This data is combined to determine the final stage (0–IV).