TUMOR DNA CONTENT AS A PROGNOSTIC INDICATOR IN SQUAMOUS-CELL CARCINOMA OF THE ORAL CAVITY AND TONGUE BASE

Background. Nuclear deoxyribonucleic acid (DNA) content is a prognosti c factor in several tumors; and decisions regarding treatment have bee n made using this parameter. Nevertheless, there is no agreement in he ad and neck cancer. The purpose of the present study was to ascertain whether tumor DNA content correlated with prognosis in cases of primar y squamous cell carcinoma (SCC) of the oral cavity and tongue base. Me thods. A retrospective study of formalin-fixed, paraffin-embedded tiss ue from patients with histologically confirmed SCG of the oral cavity and tongue base was performed using flow cytometry. Tumor DNA content was studied in 109 sets of specimens from previously untreated patient s. Ail of them underwent surgical resection at the University ''Hospit al de La Princesa'' between 1982 and 1992. Clinical parameters (age, s ex, site of primary tumor, clinical stage, adjuvant therapy received, and disease-free and overall survival) and histologic parameters (hist opathologic stage, tumor differentiation, type of inflammatory infiltr ation, presence of perineural invasion) were recorded in all cases. An exhaustive statistical analysis was applied. Results Only the histogr ams of 93 patients were adequate for consideration, in flow cytometric analysis, DNA aneuploidy was observed in 51 tumors (55%). The proport ian of aneuploid tumors was significantly higher in advanced-stage car cinomas (p <.05), tumors with perineural invasion (p <.05) and in men (p<.05). In the 24 patients with lymph node metastasis, the incidence of aneuploidy was 82% (19 of 24) (p <.05). The rate of metastasis and aneuploidy increased as the degree of differentiation decreased (p <.0 5 for both). Patients with aneuploid carcinomas in both early and adva nced stages had shorter relapse-free and overall survival periods than did the patients with diploid tumors (p <.001 for both). A Cox regres sion analysis demonstrated that ploidy was the single most important p rognostic factor in determining relapse and death (p <.001 for both). Conclusions. The results indicate that tumor DNA analysis by flow cyto metry appears to be useful as a supplement to clinical and histologic evaluation in predicting the tendency of SCG of the oral cavity and to ngue base to metastasize to regional lymph notes and to predict the ou tcome of the disease. (C) 1998 John Wiley & Sons. Inc.