Prognostic value of DNA ploidy: 5-year follow-up of patients with resectable squamous cell carcinoma (SCC) of the lung.

This study was designed to show the relation between DNA-ploidy in patients with resectable lung cancers and their 5-year survival rate. The results are compared with those from our 2-year follow-up study of the same group of patients published in 2000. The group of 80 patients with SCC who underwent lung resection between 1995 and 96 were re-analyzed. For the statistical analysis the hazard Cox model and an exponential multiple regression model were used. The survival curves were drawn using the Kaplan-Meier method. DNA-aneuploidy was found in 45% of cancer tumors. There was no statistically significant correlation between aneuploidy and gender, age, cancer staging or grading. In the 3-year follow-up the survival rate in patients with aneuploid type tumors was significantly lower than in those with the diploid type. However, this difference was not found after 5 years of follow-up. Tumor ploidy was an independent prognostic factor only in patients between 55 and 60 years of age. The mortality rate in patients with aneuploid tumors was mainly the result of distant metastases while, in patients with diploid tumors, local recurrence was the main reason for death. In the first three years after surgical resection patients with aneuploid tumors are at higher risk of distant metastases than patients with the diploid type. Tumor ploidy can be recognized as an independent prognostic factor in younger (55-60) patients. Aneuploidy promoted the occurrence of early distant metastases while the diploid type was associated with late (after 3 years) local tumor recurrence.