Is T factor of the TNM staging system a predominant prognostic factor in pathologic stage I non-small-cell lung cancer ? A multivariate prognostic factor analysis of 151 patients.

We attempted to clarify whether the T factor of the TNM staging system should be viewed as a predominant prognostic factor in patients with pathologic stage I non-small-cell lung cancer when analyzed together with various histopathologic factors and deoxyribonucleic acid ploidy pattern of tumors. We studied 151 patients who were in this stage. Histopathologic factors used in the analysis were as follows: histologic cell type (squamous or nonsquamous cell carcinoma), grade of differentiation, and tumor invasion of visceral pleura and vessels. Deoxyribonucleic acid ploidy pattern of tumors was analyzed by flow cytometry, and the tumors were classified as diploid or aneuploid tumors. Significant prognostic factors (p < 0.05) that were demonstrated by univariate analysis of survival curves were as follows: (1) T1 versus T2; (2) well versus moderately or poorly differentiated tumor; (3) the absence versus presence of tumor exposed on pleura, (4) artery invasion, (5) lymphatic vessel invasion; and (6) diploid versus aneuploid tumor. Multivariate prognostic factor analysis showed the grade of differentiation and deoxyribonucleic acid ploidy pattern to be predominant prognostic factors. The T2 tumor group had significantly more cases with tumor invasion of lymphatic vessels that did the T1 tumor group and included 18 cases with tumor exposed on pleura. When these two factors were excluded from multivariate analysis, the T factor was marginally significant (p = 0.08). These observations suggest that the T factor is not necessarily a predominant prognostic factor in pathologic stage I non-small-cell lung cancer.