Tumorstadium

Tumorstadium, or tumor stage in English, is a classification that describes the extent of cancer at a given point in time. It indicates how large the primary tumor is (T), whether cancer has spread to nearby lymph nodes (N), and whether there are distant metastases (M).

Most cancers use the TNM system, with stage groups designated from 0 to IV. Stage 0 denotes non-invasive disease in situ; stage I–III reflect increasing local invasion and regional spread; stage IV indicates distant metastasis. Some cancers have additional subdivisions to reflect tumor size or location.

Determination of tumorstadium relies on diagnostic workup: imaging (CT, MRI, PET), endoscopy or surgical exploration, and pathology from biopsies or resections. In some cancers, molecular markers provide refinements but are usually separate from the formal stage.

Stage is a major factor in prognosis and treatment decisions. Localized disease (early stages) is more likely to be treated with surgery or radiotherapy with curative intent, while advanced disease often requires systemic therapies such as chemotherapy, targeted therapy, or immunotherapy. Response to treatment can also alter the staging in follow-up.

Limitations exist: stage is an estimate of extent at a single time point and may be updated with new information. Intratumoral heterogeneity, sampling errors, and cancer biology can affect accuracy. Different cancer types have distinct staging criteria; staging should be interpreted in the context of the cancer type and patient condition.