Background: The effect of histopathologic review and subclassification on incidence rates for nonsquamous cell carcinoma (non-SCC) of the uterine cervix in the Norwegian population was evaluated.
Methods: All non-SCC from three 5-year periods (1966-70, 1976-80, and 1986-90) were reviewed, classified, and graded.
Results: Incidence rates were 1.2, 1.2, and 1.7 per 100,000 for adenocarcinoma and 0.1, 0.3, and 0.5 per 100,000 for other carcinomas in the three periods. Adenocarcinomas increased in all age groups, most markedly in women younger than 35 years. Incidence rates for both major subgroups of endocervical (EC) and endometrioid (EM) carcinomas increased for women younger than 55 years. After 1976-80, the incidence rate for EC, but not for EM, decreased in women older than 55 years. Endometrioid carcinoma became the dominant histologic subtype in 1986-90. Shifts toward lower clinical stages and younger age were found for EC, EM, and carcinoma not otherwise specified (NOS). Patients with NOS, clear cell, serous, or glassy cell/undifferentiated carcinoma were older, and their disease was diagnosed at higher stages. Distribution of International Federation of Gynecology and Obstetrics (FIGO) stages was: Stage I: 62%; Stage II: 21%; Stage III: 12%; and Stage IV: 5%. Distribution of histologic subgroups was: EC:, 24%; EM: 21%; NOS: 16%; clear cell: 7%; adenosquamous: 7%; small cell: 6%; serous: 4%; undifferentiated: 3%; and villoglandular carcinoma: 2%. Other subgroups were seen only sporadically.
Conclusions: Incidence rates of non-SCC of the uterine cervix are increasing in Norway. Improvements in diagnostic procedures may explain shifts toward lower stage and age of patients but not the observed differences between histologic subgroups.
Copyright 2000 American Cancer Society.