One of the best methods for early cancer detection and prevention is the routine, simple to perform Pap smear of the uterine cervix. The cells obtained from the surface epithelium are placed on a glass image and reviewed to determine if abnormal cells are present. Pre-neoplastic dysplasias as well as carcinomas can be detected.

Cytologic screening elsewhere in the body is less sensitive. A sputum sample can be obtained for cytology to look for abnormal cells in the respiratory tract, but it is unlikely that low stage lesions will be found.