Follow-up on flow cytometric DNA analysis of squamous cell carcinoma of the tongue.

Preliminary data from this institution suggested that flow cytometric DNA analysis was an objective prognostic indicator in archival localized squamous cell carcinoma of the tongue. Technical improvements were made, including analysis of tumor, normal tissue, and a combination of the two; standardized cursor placement; mathematic determination of tetraploid populations; and development of a statistical analysis. A larger number of patients (60) with this disease were reviewed. DNA content was related to disease-free survival, local recurrence, regional metastasis, and incidence of second primary tumors. There was no significant difference between aneuploid and diploid tumors with respect to the variables analyzed. We believe these technical improvements will enhance flow cytometric DNA analysis of paraffin-embedded tissues. However, in this retrospective review of localized squamous cell carcinoma of the tongue, DNA analysis was not a valuable prognostic indicator. Only prospective studies will address this issue.