Selected characteristics of cervical cancer incidence cases.

Selected demographic characteristics associated with incidence cases of uterine cervical squamous severe dysplasia and carcinoma were determined. The mean age at histologic detection for all patients with Papanicolaou smears at not greater than three-year intervals was 31.0 years, with a range of 19 to 63. Invasive carcinomas were predominantly of the microinvasive type, and the mean age of patients was 34.1 years. The mean interval for conversion from cytologic negativity or mild dysplasia was 2.2 years, and two basic patterns of conversion were recognized: (1) continuously increasing atypia and (2) retrogressive cytologic findings. Most instances of the latter type probably were due to inadequacies of cellular sampling. No significant correlation was found between conversion interval and age of patient. A case-control comparison of gravidity and parity showed statistically significantly higher values among index cases for both measures for ages 20 to 29 but not for 30 years or older, implicating youthful pregnancy as an etiologic factor in cervical carcinogenesis.