Conclusion: Multivariate analysis showed age, lymph node status, proliferative index in transformation border, and DNA index in the center of laryngeal squamous cell carcinoma to be significant predictors for survival. By accessing distinctive areas of the tumor we were able to reduce the impact of intratumoral heterogeneity on prognostic factors.
Objectives: Laryngeal carcinomas are characterized by considerable histological variation within the tumor. The possible effects of this morphological heterogeneity on the estimation of tumor DNA content were investigated.
Materials and methods: We analyzed 92 cases of archived, paraffin-embedded laryngeal carcinoma. For each tumor, three different regions, defined microscopically (center of tumor, transformation border, invasive border), were analyzed. DNA content was measured by flow cytometry. Three parameters were evaluated: DNA ploidy, DNA index, and proliferative index.
Results: DNA ploidy, DNA index, and proliferative index were higher in the tumor center than in the respective borders. Intratumoral differences in DNA ploidy were observed in 56 tumors (60.8%); DNA index heterogeneity was observed in 57.6% cases. Proliferative index varied greatly in morphologically different parts of the same carcinoma. DNA ploidy and DNA index of the transformation border correlated with tumor size and lymph node status. Proliferative index of the tumor center and of transformation border correlated with lymph node status, tumor size, and histological grade.