IMAGE CYTOMETRY AND CHEMOPREVENTION IN CERVICAL-CANCER

Of the approximately 60 million Pap smears performed in the United Sta tes in 1995, about 8% or 5 million will show cytology that is ''not ne gative'' (ASCUS, AGCUS, LSIL, HSIL, etc.). Possibly 15% or about 0.7 m illion of these cases will have positive follow-up by repeated Pap sme ars, colposcopy or biopsy. More than 4 million will be false-positive smears based on the reference standard of biopsy or repeated smears. I f no treatment or medical intervention was offered to the 0.7 million cytologically and histologically positive cases, perhaps 20,000 (3%) w ould develop into invasive cancer. Of the original 5 million cytologic ally ''not negative'' cases, fewer than 0.5% have the potential to dev elop into invasive cancer. While considerable attention has been paid to false-negatives in Pap screening, the above considerations indicate that the cytological and histological criteria for assessing the mali gnant potential of ''not negative'' samples might benefit from some re finement. Until such refinement occurs, any chemoprevention studies in cervix face a formidable signal-to-noise problem-worse than 1:30. Thi s paper presents data from quantitative image cytometry of cervical sm ears for assessing the malignant potential of various ''not negative'' cases. We have approached this in two ways-by analyzing dysplastic ce ll nuclei and by analyzing the nuclei of cytologically normal cells gr owing in the vicinity of the neoplastic lesion. In both cases, nuclear features describing the distribution of the DNA in the cell nuclei (e specially texture features) are the discriminating factors. Future res earch into the objective assessment of malignant potential of ''not ne gative'' cases is outlined. (C) 1995 Wiley-Liss, Inc.