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How does cancer staging describe the extent of a tumor?
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cancer
View through an endoscope of a polyp, a benign precancerous growth projecting from the inner lining of the colon.
Cancer staging is a protocol used to describe the size and dissemination of a tumor, both within the organ of origin and throughout the body. Unlike grading, which assesses the histological features and aggressiveness of cancer cells, staging focuses on the physical extent of the disease.1
The most common internationally standardized method is the TNM staging system:1
- T: Refers to the size and extent of the primary tumor.1
- N: Indicates the presence and extent of lymph node involvement.1
- M: Denotes whether the cancer has spread (metastasized) to distant parts of the body.1
Staging systems are specific to the type of cancer. For example, some cancers are categorized into stages ranging from 0 (carcinoma in situ) to IV, based on factors like the depth of invasion into tissue layers and the involvement of nearby lymph nodes. These assessments are critical for determining a patient's prognosis and selecting the most appropriate treatment approach.21