Influence of preoperative radiotherapy on DNA ploidy in squamous cell carcinomas of the oesophagus.

The influence of preoperative radiotherapy on the prevalence of DNA aneuploidy and the prognostic significance of tumour DNA ploidy was evaluated in 126 patients with squamous cell carcinoma of the oesophagus. Preoperative radiotherapy with 30 Gy was performed in 52 patients. DNA ploidy was analysed by flow cytometry on nuclei isolated from paraffin embedded tumour tissue. DNA aneuploidy was identified in 75 tumours (61%) and found to correlate significantly with tumour stage. The percentage of aneuploid carcinomas was significantly reduced by preoperative radiotherapy (surgery only group, 71%; radiotherapy group, 47%, p = 0.01). Although the median survival time was slightly better in the diploid than in the aneuploid group (11.3 and 8.0 months respectively), this difference was not statistically significant. A curative tumour resection was the most important prognostic factor. Preoperative radiotherapy did not prolong survival in oesophageal cancer.