Cervical cancer in women under 30 years of age in Norway: a population-based cohort study.

Background We compared women with incident cervical cancer under the age of 30 with older women with regard to stage, morphology, screening history and cervical cancer mortality in a population-based cohort study. Methods We included data from the Cancer Registry of Norway. Incidence rates (per 100,000 women-years) were calculated and joinpoint regression was used to analyse trends. The Nelson-Aalen cumulative hazard function for risk of cervical cancer death during a 15-year follow-up was displayed. The hazard ratios (HRs) of cervical cancer mortality with 95% confidence intervals (CIs) were derived from Cox regression models. Results The incidence of cervical cancer in women under the age of 30 has almost tripled since the 1950s, with the steepest increase during 1955-80 (with an annual percentage change (APC) of 7.1% (95%CI 4.4-9.8)) and also an increase after 2004 (3.8% (95%CI -1.3-9.2)). Out of 21,160 women with cervical cancer (1953-2013), 5.3% were younger than 30 years. A lower proportion of younger women were diagnosed at more advanced stages and a slightly higher proportion were diagnosed with adenocarcinoma and adenosquamous carcinoma comparing women above 30 years. The cumulative risk of cervical cancer death was lower for patients under the age of 30. However, the difference between the age groups decreased over time. The overall adjusted HR of cervical cancer mortality was 0.69 (95% CI 0.58-0.82) in women diagnosed under the age of 30 compared to older women. Conclusion There has been an increase in cervical cancer incidence in women under the age of 30. Cervical cancer in younger women was not more advanced at diagnosis compared to older women, and the cervical cancer mortality was lower.