Adherence to international recommendations in the governance and organisation of Nordic cervical cancer screening programmes

Association of COVID-19 Pandemic with Colorectal Cancer Screening: Impact of Race/Ethnicity and Social Vulnerability

BACKGROUND

The COVID-19 pandemic disrupted health care delivery, including cancer screening practices. This study sought to determine the impact of the COVID-19 pandemic lockdown on colorectal cancer (CRC) screening relative to social vulnerability.

METHODS

Using the Medicare Standard Analytic File, individuals 65 years old or older who were eligible for guideline-concordant CRC screening between 2019 and 2021 were identified. These data were merged with the Center for Disease Control Social Vulnerability Index (SVI) dataset. Changes in county-level monthly screening volumes relative to the start of the COVID-19 pandemic (March 2020) and easing of restrictions (March 2021) were assessed relative to SVI.

RESULTS

Among 10,503,180 individuals continuously enrolled in Medicare with no prior diagnosis of CRC, 1,362,457 (12.97%) underwent CRC screening between 2019 and 2021. With the COVID-19 pandemic, CRC screening decreased markedly across the United States (median monthly screening: pre-pandemic [n = 76,444] vs pandemic era [n = 60,826]; median Δn = 15,618; p < 0.001). The 1-year post-pandemic overall CRC screening utilization generally rebounded to pre-COVID-19 levels (monthly median screening volumes: pandemic era [n = 60,826] vs post-pandemic [n = 74,170]; median Δn = 13,344; p < 0.001). Individuals residing in counties with the highest SVI experienced a larger decline in CRC screening odds than individuals residing in low-SVI counties (reference, low SVI: pre-pandemic high SVI [OR, 0.85] vs pandemic high SVI [OR, 0.81] vs post-pandemic high SVI [OR, 0.85]; all p < 0.001).

CONCLUSIONS

The COVID-19 pandemic was associated with a decrease in CRC screening volumes. Patients who resided in high social vulnerability areas experienced the greatest pandemic-related decline.

Divergent effects of switching from cytology to HPV-based screening in the Nordic countries

BACKGROUND

Cervical cytology has been the primary method of cervical cancer screening for decades. Tests that detect viral HPV are shown in several randomized trials to provide better protection against cancer compared with cytology. HPV-based screening has been implemented alongside cytology in the Nordic countries for several years. The aim of this study was to compare cytology and HPV-based screening in the colposcopy referrals and detection rates of cervical lesions.

METHODS

Individual-level screening data from Finland, Iceland, Norway and Sweden were harmonized and aggregated locally. We utilized data for tests taken during years 2015-17 and biopsies taken during years 2015-19 to allow 24 months of follow-up. Age-standardized estimates and age-adjusted risk ratios for six different outcomes of screening management were calculated.

RESULTS

The age-standardized colposcopy rates were higher in HPV-based testing compared with cytology in Finland (3.5% vs. 0.9%) and Norway (6.0% vs. 4.1%) but lower in Sweden (3.7% vs. 4.9%). The relative detection rate of cervical intraepithelial neoplasia grade 2 and above in HPV-based testing compared with cytology was highest in Finland (RR 2.37, 95% CI 2.13-2.63) and Norway (RR 1.66, 95% CI 1.57-1.72) while in Sweden the difference was not statistically significant (RR 0.98, 95% CI 0.95-1.00).

CONCLUSIONS

The effects of implementing HPV screening varied by country as different screening algorithms were implemented. HPV-based screening increases colposcopy rates mainly through referrals from increased repeat testing and detection rate is therefore significantly higher compared with cytology. Monitoring of these indicators in subsequent rounds of HPV-based screening remains essential.

Setting the record straight-Correcting uterine cancer incidence and mortality in the Nordic countries by reallocation of unspecified cases

INTRODUCTION

The incidence of and mortality from cancers of the cervix uteri and corpus uteri are underestimated if the presence of uterine cancers, where the exact topography (site of origin) is not specified, is omitted. In this paper we present the corrected figures on mortality from and incidence of cervix and corpus uteri cancers in the Nordic countries by reallocating unspecified uterine cancer deaths and cases to originate either from the corpus uteri or cervix uteri. To further validate the accuracy of reallocation, we also analyzed how well the reallocation captures the changes occurring as the result of a transition in cause of death coding in Norway that took place in 2005.

MATERIAL AND METHODS

This study uses data available in the NORDCAN database, which contains aggregated cancer data from all the Nordic countries for the years 1960-2016. The unspecified uterine cancer cases and deaths were reallocated to either cervix uteri or corpus uteri based on the estimated probability that follows the distribution of cases and deaths with verified topography. The estimated proportions of cases and deaths for both cancers were calculated for each combination of age group, year, and country as a proportion of cases (and deaths, respectively) with known topography. Annual age-standardized rates were calculated by direct age-adjustment.

RESULTS

The proportions of unspecified uterine cancers were higher in the mortality data than in incidence data, with mean values for 1960-2016 ranging between 5.1% and 26.6% and between 0.2% and 6.8% by country, respectively. In the Nordic countries combined, the reallocation increased the number of cases by 4% and deaths by approximately 20% for both cancers. Finland was the only Nordic country where the mortality rate did not increase substantially after reallocation.

CONCLUSIONS

The reallocation procedure had a significant impact on mortality from cancers of the cervix and corpus uteri for countries where the proportion of cancer deaths coded as uterus, not otherwise specified, is substantial. More effort to validate cause of death data with incidence data from cancer registries is warranted to avoid erroneous conclusions of temporal trends based on uncorrected cancer burden.

Cervical screening during the COVID-19 pandemic: optimising recovery strategies

Disruptions to cancer screening services have been experienced in most settings as a consequence of the COVID-19 pandemic. Ideally, programmes would resolve backlogs by temporarily expanding capacity; however, in practice, this is often not possible. We aim to inform the deliberations of decision makers in high-income settings regarding their cervical cancer screening policy response. We caution against performance measures that rely solely on restoring testing volumes to pre-pandemic levels because they will be less effective at mitigating excess cancer diagnoses than will targeted measures. These measures might exacerbate pre-existing inequalities in accessing cervical screening by disregarding the risk profile of the individuals attending. Modelling of cervical screening outcomes before and during the pandemic supports risk-based strategies as the most effective way for screening services to recover. The degree to which screening is organised will determine the feasibility of deploying some risk-based strategies, but implementation of age-based risk stratification should be universally feasible.

Comparison of cytology and human papillomavirus-based primary testing in cervical screening programs in the Nordic countries

OBJECTIVE

To compare primary test positivity in cytology and human papillomavirus-based screening between different Nordic cervical cancer screening programs using harmonized register data.

METHODS

This study utilized individual-level data available in national databases in Finland, Iceland, Norway, and Sweden. Cervical test data from each country were converted to standard format and aggregated by calculating the number of test episodes for every test result for each calendar year and one-year age group and test method. Test positivity was estimated as the proportion of positive test results of all primary test episodes with a valid test result for "any positive" and "clearly positive" results.

RESULTS

The age-adjusted rate ratio for any positive test results in primary human papillomavirus-based screening compared to cytology was 1.66 (95% CI 1.64-1.68). The age-adjusted rate ratio for clearly positive test results was 1.02 (95% CI 1.00-1.05). A decreasing rate ratio by age was seen in both any positive and clearly positive test results. Test positivity increased over time in Iceland, Norway, and Sweden but slightly decreased in Finland.

CONCLUSIONS

The probability of any positive test result was higher in human papillomavirus testing than in primary cytology, even though the cross-sectional detection of a clearly positive test result was the same. Human papillomavirus testing can still lead to an improved longitudinal sensitivity through a larger number of follow-up tests and the opportunity to identify women with a persistent human papillomavirus infection. Further research on histologically verified precancerous lesions is needed in primary as well as repeat testing.