Lung Cancer Staging

Staging and Grading

Staging refers to the diagnostic procedure following the diagnosis of a malignant tumor. In addition to histology, staging plays a decisive role in the choice of therapy and the prognosis. Staging assesses the spread of the tumor in the organism.

Grading is also performed as part of staging. In this process, the tumor cells are classified according to their differentiation. Differentiation in this case means the extent to which the cells from the biopsy obtained still resemble the cells from which they originated (bronchial cells).

Four levels are distinguished: G1 – the tumor cells are well differentiated, i.e. they resemble the original tissue except for minor changes G2 – moderately differentiated cells G3 – poorly differentiated cells G4 – the cells are undifferentiated, i.e. they are no longer recognizable as former bronchial cells. Grading tells us something about the aggressiveness and growth rate of the tumor.

The more undifferentiated the cells are, the faster and more aggressive they grow into the surrounding tissue. To evaluate the spread of solid tumors, the so-called TNM classification is used, which is used to classify the disease into different stages. T stands for tumor and evaluates the local spread of the tumor in the tissue, N stands for node and evaluates the infestation of the lymph nodes, M stands for metastasis and refers to the presence of metastases of the tumor in the organism.

Numbers are assigned to each of the letters, e.g. T usually has 4 degrees of spread. Based on the TNM classification, the stages are divided from I to IV. Stage I means localized tumor without lymph node involvement and without metastases, stage IV means the presence of metastases.

Stage II and III are tumors with greater local spread and/or different lymph node involvement. A simpler classification is often used for small-cell bronchial carcinoma, where there are only two stages:

  • Limited disease (approx. 35% at diagnosis): Limited to one half of the lung without affecting the lymph nodes or the pleura (pleura, serous skin around the lung).
  • Extended disease (approx. 65 %) all other stages.