Changing epidemiology of cervical cancer in Scotland: an analysis of the national cancer registration data by age and time period, 1971-2020

Background

Worldwide, cervical cancer is the 4th most common cancer in women. The highest incidence is observed in Africa (26.4/100,000) and the lowest in North America (6.4/100,000). Over 99% of cases are caused by infection with Human Papillomavirus (HPV). In the UK, a national cervical screening programme was rolled out in 1988 and HPV vaccination has been offered to girls aged 12-13 years since 2008. Recently, the WHO launched a global Cervical Cancer Elimination Initiative, and the NHS England set an ambition to eliminate cervical cancer by 2040. We conducted a retrospective population-based cohort study to examine whether there have been changes in the incidence of cervical cancer in Scotland over the past five decades.

Methods

Anonymised individual level data for women diagnosed with cervical cancer during 1971-2020 were obtained from the Scottish Cancer Registry. Average annual incidence rates (AAIRs) were calculated for the three age categories (15-24, 25-64, 65+ years) and all ages combined during the 10 five-year time periods (1971-75 to 2016-20).

Results

During the 50-year study period, a total of 18,408 women with cervical cancer were registered in Scotland (female population, 2.8 million). In women aged 15-24 years, the AAIRs declined by about 15%; in women aged 25-64 years, the rates initially increased and then declined by about 30% (from 24.9/100,000 in 1986-90 to 17.4/100,000 in 2016-20). Similarly in women aged 65+ years, the rates initially increased and then declined by about 61% (from 25.7/100,000 in 1986-90 to 10/100,000 in 2016-20). At all ages combined, the rates declined by 31%. During the 2016-20 period, 71% of the women were diagnosed at an early Stage 1 or 2. With regard to the mode of detection, about half (52%) of the women aged 25-64 years (i.e., in the screening age group) were diagnosed after clinical presentation and half (47%) via the screening programme. In contrast, the large majority (97%) of women aged 65+ years were diagnosed after clinical presentation and only 2% via screening, and about 45% had advanced Stage 3 or 4 disease.

Conclusion

Considering the consistent decline in the incidence of cervical cancer from 1986-90 onwards, it appears that Scotland is making steady progress to eliminate cervical cancer by 2040. Our findings inform public health policy to extend the age for HPV vaccination and cervical screening. To support WHO initiative, there is an urgent need to promote low- and middle-income countries to roll out HPV vaccination and screening programmes.