Prognostic significance of DNA cytometry of postirradiation cervicovaginal smears.

Abstract

Cytologic sampling is performed routinely after radiotherapy for cervical carcinoma. The prognostic significance of postirradiation dysplastic and atypical cells is uncertain because of difficulties in distinguishing preneoplastic and cancerous changes from benign radiation changes. DNA cytometry studies may provide a more objective method of identifying significant lesions. Postirradiation cervical carcinoma patients with cervical/vaginal smears containing atypical or dysplastic cells were identified prospectively. Papanicolaou smears were destained, restained with a Feulgen stain, and evaluated for DNA content using image cytometry. Pathologic and clinical records were monitored on each patient for evidence of recurrence or biopsy-proven dysplasia. Of 46 patients, 14 had been diagnosed on cytology as having atypical squamous cells, 4 as having atypical/suspicious cells, 12 with low grade squamous intraepithelial lesions (SIL), 3 with high grade SIL, and 13 with ungraded SIL. DNA histograms were classified as follows: 14 diploid, 19 polyploid, and 13 aneuploid. Cytologic diagnosis and histogram type were correlated significantly and both correlated with clinical outcome. The probability of either postirradiation dysplasia or recurrence was as follows: SIL, 82%; suspicious, 100%; polyploid, 79%; and aneuploid, 92%. Patients with atypical squamous cells of undetermined significance or diploidy most frequently had negative follow-up (57% each). All patients with both SIL and aneuploidy developed either dysplasia or recurrence. The stage of disease did not correlate with outcome or histogram pattern. DNA analysis of postirradiation cytologic smears demonstrating atypia or dysplasia may provide useful ancillary information. The presence of aneuploidy usually signifies either recurrence or dysplasia. Polyploidy most frequently occurs in dysplastic processes, whereas diploid histograms usually denote a benign disease course.