On the origin and histological structure of adenocarcinoma of the endocervix in women under 50 years of age.

In the last 10 years 28 adenocarcinomas of the endocervix developing in women up to the age of 50, have been encountered at our clinic. Of these women, 23 (82%) had taken oral contraceptives, in most instances continuously for up to 19 years, and for a median of 10 years. During the same period of time, 12 adenocarcinomas in situ of the endocervical mucosa were seen, 11 of which developed after 1 to 20 years of use of oral contraceptives. In contrast, only 40% of women with invasive squamous carcinoma under age 50 had used oral contraceptives. Fourteen of the 23 patients with invasive adenocarcinomas and 9 patients with adenocarcinoma in situ had taken contraceptives containing a potent gestagen, Norgestrel; the others had taken either Norethisterone acetate or Lynestrenol, usually in relatively high doses. Microscopically, the adenocarcinoma in the 28 women occurred in 3 forms, two of which did not appear in the 5 noncontraceptive users. In the women taking oral contraceptives, microglandular hyperplasia of the endocervix was diagnosed either prior to or coincident with the adenocarcinoma. The clinical observations are supported by experimental findings: 2 of 12 rhesus monkeys treated for 10 years with medroxyprogesterone acetate at doses 50 times those prescribed for women developed a similar type of adenocarcinoma. The longterm use of synthetic gestagens may be causally related to the development of endocervical adenocarcinoma.