Flow cytometric DNA ploidy analysis in hypopharyngeal cancer as a predictor for malignant potential, response to radiotherapy, and outcome

Flow cytometric DNA ploidy analysis was performed on paraffin-embedded tissue from 27 patients with squamous cell carcinoma of the hypopharynx. Seventeen of 27 tumors were aneuploid and 10 were diploid. DNA ploidy and DNA index were not correlated with TN stage, histologic differentiation, tumor location, or prognosis. However, aneuploid tumors responded better to radiotherapy than did diploid tumors (p<0.05), and tumors with distant metastases had higher DNA indices (p<0.05). We classified patients into four groups on the basis of DNA ploidy status and response to radiotherapy; survival of patients in these groups, in order or decreasing length, was: diploid with complete response, aneuploid with complete response, diploid with partial response, and aneuploid with partial response (p<0.02). DNA ploidy analysis may be used with clinical and histological parameters to predict response to radiotherapy and long-term tumor control in hypopharyngeal cancer, and may prove to be valuable when planning treatment. (author)