In order to describe the real biological behavior of the small-cell lung ca
ncer we have analyzed survival rates of 66 patients with small-cell lung ca
ncer who did not receive any specific anti cancer therapy. Also, objective
of this study was to evaluate the staging system of the small-cell lung can
cer. Untreated small-cell lung cancer patients with limited stage disease h
ad statistically significant (p < 0.05) better survival rates in comparison
to patients with extensive stage disease. T and N factor of the TNM classi
fication did not influence the survival in untreated small-cell lung cancer
patients. It appears that the TNM staging system is not predicting surviva
l probabilities of untreated patients with small-cell lung cancer, while th
e two-stage system appeared very well based on survival probabilities of th
ese patients.