Introduction: Knowledge of prognostic factors is important for therapeutic decision making but above all, at a population level, for the interpretation of data in the literature and as a guide to clinical research. To be useful in practice they must be both independent and reproducible. Despite an impressive number of publications few descriptions achieve this standard in lung cancer.
Background: The TNM classification plays a predominant role in the choice of treatment, in prognosis and as an index of performance. Depending on the population studied (small cell or non-small cell cancer, operable or not) other independent factors, identified in large series, improve the prediction of prognosis: sex, age, loss of weight, LDH, leukocytosis, neutrophilia, haemoglobin, serum calcium, NSE, Cyfra 21-1.
Viewpoint: The numerous biological factors described should be the object of further investigations but may lead to the assessment of new therapeutic strategies.
Conclusion: Large multicentre studies are essential before a role may be attributed to an independent prognostic factor and before it may be used as a guide to the management of a patient or to improve our prediction of the progress of a patient or a group of patients.