Cancersstadiet

Cancersstadiet, or cancer stage, is a measure of how far a cancer has spread in the body at diagnosis or over time. It describes the extent of disease and is used to guide treatment decisions, estimate prognosis, and compare outcomes between patients and over time.

The most widely applied framework is the TNM system, developed by international cancer organisations. T describes the size and local invasion of the primary tumor, N indicates regional lymph node involvement, and M denotes distant metastasis. Each cancer type has specific criteria for what counts as T, N, and M, and the results are combined into an overall stage group.

Staging is commonly presented as stages 0 through IV, though variations exist. Stage 0 refers to non-invasive disease in situ. Stage I usually denotes a smaller, localized tumor with limited or no spread. Stages II and III reflect larger size or more extensive local invasion and/or nodal spread. Stage IV indicates distant metastasis. Some cancers use subcategories (such as A, B) or different staging schemes, and stage groups can differ between cancer types.

Staging relies on clinical assessment and diagnostic tests, including imaging (for example CT, MRI, PET), endoscopy, and biopsy. Surgical pathology can provide the definitive (pathological) stage, and in some cancers, molecular or biomarker information may refine staging and prognosis.

The stage influences treatment planning: early-stage cancers are often managed with surgery and/or radiation with curative intent, while advanced stages may require systemic therapies and palliative care. Staging may be revised over time with restaging tests as treatment progresses or disease evolves.