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Preface (continued) |
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The
definitions and stage grouping rules are shown
on pages 5-10. A further objective is to answer
questions regarding application of the TNM
definitions and stage
grouping rules to clinical situations for which there is no specific rule.
The contribution of various imaging modalities to the assessment of the disease
extent are illustrated and some problems in interpretation are addressed.
In the milieu of evolving knowledge of the molecular biology of lung cancer, its initiation, growth, and metastasis, the stage of disease remains as a benchmark for evaluating the effect on survival of new factors derived from this research8-10. Staging defines the success or failure of treatment for specific groups of patients. It allows valid estimates of prognosis that may be used reliably as guidelines for selecting treatment and comparing the results of differing treatments.
A useful staging system could not take into account the innumerable factors that may exert an influence on the outcome of patients with lung cancer. However, patients that have similar options for treatment and expectations for survival may be assigned to the same stage group. Most patients are not treated surgically and elements that are determined only from pathological examination of resected specimens are not included in the definitions and stage grouping rules. It is the CLINICAL determination of disease extent that is the basis for initial treatment planning.
The clinical classification, "cTNM", based on all diagnostic and evaluative information obtained before treatment is started, should be assigned for each patient and not changed throughout the course of the disease. The TNM definitions are appropriate for surgical-pathologic staging, "pTNM", based on pathologic examination of resected specimens; for retreatment staging, "rTNM", following the initial or subsequent steps in a multistep treatment program, or for staging at any other specific time in the life history of the disease. The use of identical definitions is essential for each type of classification.
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