[Prognostic significance of the DNA ploidy of the early glottic cancer].

The stage classification is most frequently used at the present in predicting the outcome of laryngeal carcinoma. Recently, DNA ploidy pattern as detected by DNA flow cytometry and cytofluorometry has been also shown to be predictive. In this study, DNA cytofluorometry was performed on formalin-fixed paraffin-embedded tissues from 18 patients with T1 and T2 glottic squamous cell carcinoma for whom long-term follow-up data were available. The DNA ploidy pattern was classified into three types, diploid, diploid + tetraploid and aneuploid according to the DNA content of Go/G1 cells and mitotic cells. In these 18 cases, 8 cases (44%) had diploid pattern, 3 cases (17%) had the diploid + tetraploid pattern and 7 cases (39%) had the aneuploid pattern. The ploidy pattern was significantly associated with the relapse-free rate, but did not correlate with the stage of the carcinoma and differentiation of the cancer cells. Distribution of the patients by histology, stage and therapy was almost equal among the diploid, diploid + tetraploid and aneuploid groups. All the patients were treated with irradiation (60Gy). In the group as a whole, no patient died of glottic carcinoma. Relapse-free survival rates for diploid, diploid + tetraploid and aneupoid were 88%, 33% and 29% respectively. This retrospective study of glottic cancer treated with radiation therapy suggests the possibility that the DNA ploidy pattern would significantly predict patient outcome and would be useful for selecting patients whose poor prognosis demands more aggressive therapy.