Flow cytometric DNA analysis and lysosomal cathepsins b and l in locally advanced laryngeal cancer. Relationship with clinicopathologic parameters and prognostic significance

Abstract

The traditional factors of locally advanced laryngeal squamous cell carcinoma (LSCC) have limited predictive value for the identification of high risk patients. Therefore, it is extremely important to define prognostic factors that identify the more aggressive types. Reliable and reproducible prognostic indicators are being investigated to help clinicians identify high risk groups and address more rational treatment. Flow cytometric DNA ploidy and S-phase fraction (SPF) measurements were performed on frozen tumor tissues from a consecutive series of 71 patients with Stage III and IV LSCC: Lysosomal cathepsin B and L activity levels were determined biochemically in matched paired sets of tumor tissue and normal mucosa samples. By univariate analysis, lymph node positivity, poor histologic differentiation, DNA aneuploidy, high SPF, and high tumor/mucosa ratio of cathepsin B activity were significantly related to risk of relapse, whereas only DNA aneuploidy and high SPF proved to be significantly related to risk of death. Multivariate analysis showed that high histologic grade and high SPF values (> 15.1%) were independent prognostic factors related to risk of relapse (relative risk [RR] = 3.54; 95% confidence limits [CL] = 1.05-12.0; and RR = 4.22; CL = 1.54-11.6, respectively), whereas only high SPF was related to risk of death (RR = 3.63; CL = 1.17-11.3). S-phase fraction is an independent predictor of relapse free and overall survival in patients with locally advanced LSCC. On the basis of these findings, SPF should be used in addition to other established prognostic factors to refine the prognostic assessment of these patients further. More studies are needed for a better evaluation of the prognostic significance of DNA ploidy and that of lysosomal cysteine proteinases in these tumors.