Incidence rates and temporal trends of cervical cancer relating to opportunistic screening in two developed metropolitan regions of Brazil: a population-based cohort study

BACKGROUND: Brazilian opportunistic screening programs for cervical cancer have limited impact. In the regions of two cities (Campinas and Curitiba) with high human development indices, consistent information from 96-97% of all cervical cancer cases managed within the public healthcare system is available. OBJECTIVE: To estimate the incidence rate (IR) and temporal trends in these regions, covering 2001-2012. DESIGN AND SETTING: A population-based cohort study was conducted under the assumption that all cervical cancer cases were managed in cancer referral center hospitals. METHODS: 3,364 records (1,646 from Campinas; 1,718 from Curitiba) were analyzed to provide estimates of IR, age-standardized IR (ASR) and cervical cancer trends (shown per 100,000 women/year). Longitudinal patterns were analyzed using linear regression and shown as annual percentage change (APC); P < 0.05 for significance. RESULTS: Annual IR and ASR estimates for cervical cancer ranged from 3.8 to 8.0 over 2001-2012, decreasing over more recent years, and were similar for the two regions. The age-specific IR was about 50% lower among women aged 45 years or older (IR-2001/IR-2012: Campinas = 14.8/8.0; Curitiba = 18.7/8.3; P < 0.001). There was an increasing APC trend in Campinas among women aged 15-24 years, and a decreasing IR trend for squamous-cell histology in both regions (P < 0.05). CONCLUSION: Cervical cancer incidence estimates showed slowly decreasing trends in both regions, most evidently for women aged 45 years or older and for squamous-cell histology. These findings reflect the opportunistic nature of the population screening program, despite the comparatively high economic development level in the two regions.