Cervical adenocarcinoma and oral contraceptives.

English data comparable to US data on the incidence of cervical cancer are reported. Annual numbers of registrations of cervical cancer from 1968-82 were obtained from the South Thames Oxford and West Midlands cancer registries. The cases were divided into adenocarcinoma squamous cell carcinoma and unknown and cancer. Incidences were calculated in the 20-34 35-54 and 55 and older age groups and for the periods 1968-72 1973-77 and 1978-82. Within each age group the incidences were standardized for age by the indirect method using 5 year age groups; the 1968-82 rates for South Thames were taken as standard. According to the table the incidence of adenocarcinoma of the cervix in women under age 35 increased from 2.4-6.6 million between 1968-72 and 1978-82. The incidences of squamous and unclassified carcinomas also increased. Adenocarcinoma as a proportion of all cervical cancers increased from 5.7% to 7.6% in this age group. In women aged 35-54 the incidences of both squamous carcinoma and adenocarcinoma declined but the proportion of cervical adenocarcinomas increased from 8.9% to 10.5%. In women over 55 years the incidence of both squamous carcinoma and adenocarcinoma declined slightly; the relative proportion of each histological type changed little. In England as in the US there has been a marked increase in the incidence of adenocarcinoma in young women which cannot be explained by more accurate classification of previously unspecified cancer. Squamous cell cancer also has increased in England but to a lesser extent. The data provide limited support to the suggestion that the 2 histological types may have different etiologies.