Although human papillomavirus infection plays a role in the development of both cervical adenocarcinoma (AC) and squamous-cell carcinoma (SCC) of the cervix, cytological screening has been less effective in lowering the incidence of AC and its mortality rate in the United States. In contrast to SCC, only the immediate precursor of AC, adenocarcinoma in situ (AIS), has been clearly defined. In addition, the microscopic findings in AC are more diverse, and pathologists have less experience in diagnosing AC and AIS compared with SCC and its preceding lesions.
The investigators undertook a detailed pathological review of subtypes of cervical AC. The study population consisted of 154 women ranging in age from 18 to 69 years who, when seen at one of six US medical centers in the years 1992–1996, received a diagnosis of in situ or invasive AC, adenosquamous (AS) tumor, or other rare cervical glandular tumors. Three pathologists jointly carried out a microscopic review of these tumors, and risk factors were identified from questionnaires administered by interviewers.
In general, there were no substantial epidemiological differences between women with different histopathological subtypes. Nearly one-fourth of the 154 cervical glandular tumors (23%) were AIS; the remaining 77% were invasive neoplasms. Of the invasive cancers, 45% were AC; 19% were AS; and 20 were unusual types such as adenoid basal, small cell, and undifferentiated carcinomas. A majority of AIS lesions and invasive ACs exhibited endocervical or endometrioid differentiation. Nearly 80% of AS cases were grade 2 or 3, whereas 80% of ACs was grade 1 lesions. Invasive AS tumors were much likelier than ACs to exhibit vascular invasion (42% vs. 10%). AIS was likelier to be present in AC than in AS cases (71% vs. 39%). Approximately two-thirds of carcinomas of any type were stage IB when diagnosed. Both AIS and cribriform patterns were more common in ACs exhibiting cervical intraepithelial neoplasia (CIN). Nonendometrioid ACs were higher-grade tumors than endometrioid lesions. There was no evidence that microglandular hyperplasia was associated with the use of oral contraceptives.
These findings show that cervical AS tumors have more aggressive characteristics than do ACs. In addition, AIS may not be a common precursor of AS tumors, making it less likely that screening for AIS or CIN will detect these tumors an early stage.