Research Article: Increasing Cervical Cancer Screening Coverage: A Randomised, Community-Based Clinical Trial

Date Published: January 24, 2017

Publisher: Public Library of Science

Author(s): Amelia Acera, Josep Maria Manresa, Diego Rodriguez, Ana Rodriguez, Josep Maria Bonet, Marta Trapero-Bertran, Pablo Hidalgo, Norman Sànchez, Silvia de Sanjosé, Carlo Federico Perno.


Opportunistic cervical cancer screening can lead to suboptimal screening coverage. Coverage could be increased after a personalised invitation to the target population. We present a community randomized intervention study with three strategies aiming to increase screening coverage.

The CRICERVA study is a community-based clinical trial to improve coverage of population-based screening in the Cerdanyola SAP area in Barcelona.A total of 32,858 women residing in the study area, aged 30 to 70 years were evaluated. A total of 15,965 women were identified as having no registration of a cervical cytology in the last 3.5 years within the Public Health data base system. Eligible women were assigned to one of four community randomized intervention groups (IGs): (1) (IG1 N = 4197) personalised invitation letter, (2) (IG2 N = 3601) personalised invitation letter + informative leaflet, (3) (IG3 N = 6088) personalised invitation letter + informative leaflet + personalised phone call and (4) (Control N = 2079) based on spontaneous demand of cervical cancer screening as officially recommended. To evaluate screening coverage, we used heterogeneity tests to compare impact of the interventions and mixed logistic regression models to assess the age effect. We refer a “rescue” visit as the screening visit resulting from the study invitation.

Among the 13,886 women in the IGs, 2,862 were evaluated as having an adequate screening history after the initial contact; 4,263 were lost to follow-up and 5,341 were identified as having insufficient screening and thus being eligible for a rescue visit. All intervention strategies significantly increased participation to screening compared to the control group. Coverage after the intervention reached 84.1% while the control group reached 64.8%. The final impact of our study was an increase of 20% in the three IGs and of 9% in the control group (p<0.001). Within the intervention arms, age was an important determinant of rescue visits showing a statistical interaction with the coverage attained in the IGs. Within the intervention groups, final screening coverage was significantly higher in IG3 (84.4%) (p<0.001). However, the differences were more substantial in the age groups 50–59 and those 60+. The highest impact of the IG3 intervention was observed among women 60+ y.o with 32.0% of them being rescued for screening. The lowest impact of the interventions was in younger women. The study confirms that using individual contact methods and assigning a fixed screening date notably increases participation in screening. The response to the invitation is strongly dependent on age. NCT01373723

Partial Text

Despite numerous recommendations calling for the implementation of organised cancer screening programmes, cervical cancer screening remains opportunistic in many European countries. In Spain, the age-standardized incidence rate of cervical cancer remains relatively low compared to many European countries with an estimated rate around 7.8 per 105 women for 2012 and a mortality rate of 2.1 per 105[1–3]. However, cervical cancer mortality rates have stopped to decline in the last decade [4].

The CRICERVA study [15, 16] is a cluster randomised community-based clinical trial implemented within the Cerdanyola Primary Health Care Service (SAP Cerdanyola). SAP Cerdanyola is a predefined geographical area located in the metropolitan belt of Barcelona, Spain (S1 File Published protocol S2 File.- Study protocol Spanish, S3 File.- Study protocol English translation, S4 File.- Consort Checklist). It is subdivided into five Basic Health Care Centers, four of which were included in the CRICERVA study. The fifth one is an upper- class residential area, socially very distinctive from the other areas, and excluded in this study.

Population-based coverage was estimated at baseline and after the intervention. Baseline coverage relates to a 3.5 year period. Final coverage computes the baseline screening estimated through our records plus the screening referred to take place within the private sector plus the screening obtained through the rescue visit. Coverage estimates were stratified by age and by intervention group and. Overall coverage was calculated by age-weighted for each arm. Chi-square tests were used to compare intervention and control groups in terms of participation.

Approval of this study was granted by the Ethics Committee of the IDIAP Jordi Gol. No written signature was requested to participants as the study involved regular clinical practice. This was approved by the Ethical Committee.

Table 1 summarizes the different components of coverage in the 26,744 women targeted in the intervention groups(IGs) and 4,694 women in the control group (Table 1). All women in the IGs received an invitation letter with a specific date of the visit.

To our knowledge, this is the first population-based randomized trial designed to increase cervical cancer screening coverage in Catalonia. The study confirmed that an active search for women to undergo screening for cervical cancer considerably increased participation rates among all age groups and particularly so among women over age 49. Coverage post-intervention was 34% higher than that observed under strict opportunistic screening. This improvement was likely due to the provision of better information regarding screening and the invitation to participate and this had a relevant effect among the elder target women. No major absolute differences were observed between interventions strategies used. The trial identified a substantial number of women that had never had a screening test, adding additional value to the study intervention and confirmed a proportion of women attending private practice.

The study confirms that using individual contact methods and assigning a fixed screening date notably increases participation in screening. The response to our invitation process was strongly dependent on age. The findings from this study could be used to facilitate the implementation of effective population-based strategies toward the transition from opportunistic to organised cervical cancer screening.




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