Long-term follow-up of cervical cancer incidence after normal cytological findings.

An increase in cervical cancer incidence in Sweden from 2014 to 2015 has been attributed to an increase in false-negative cytological findings before cancer diagnoses. Years later, we performed a long-term follow-up to investigate whether the problem persisted. At each calendar year from 2016 to 2020, we identified women with prior normal cervical screening results through linkage to the Swedish National Cervical Screening Registry. We reported their incidence rates (IRs) of invasive cervical cancer in consecutive years and compared the IRs over time. For the years 2016 to 2020, there was no overall change in cervical cancer incidence after two normal cytology in the last two screening intervals. However, there was a further 62% increase among women 50 to 60 years of age with normal cytology in the past two screening intervals. The incidence rate of cervical cancer was high among nonscreened women and low among HPV-screened women with negative results, with no trends over time. Our results imply that the previously reported decrease in sensitivity of cervical cytology is persisting. Although primary cytology screening is no longer used, cytology is used in triaging among HPV-positive women. Our findings suggest that improved triaging is needed, for example, improved quality assurance and/or use of alternative triage tests.

Incidence of oncogenic HPV infection in women with and without mental illness: A population-based cohort study in Sweden.

BACKGROUND: Women with mental illness experience an increased risk of cervical cancer. The excess risk is partly due to low participation in cervical screening; however, it remains unknown whether it is also attributable to an increased risk of infection with human papillomavirus (HPV). We aimed to examine whether women with mental illness had an increased infection rate of HPV compared to women without mental illness. METHODS AND FINDINGS: Using a cohort design, we analyzed all 337,116 women aged 30 to 64 and living in Stockholm, who had a negative test result of 14 high-risk HPV subtypes in HPV-based screening, during August 2014 to December 2019. We defined women as exposed to mental illness if they had a specialist diagnosis of mental disorder or had a filled prescription of psychotropic medication. We identified incident infection of any high-risk HPV during follow-up and fitted multivariable Cox models to estimate hazard ratios (HR) with 95% confidence intervals (CI) for HPV infection. A total of 3,263 women were tested positive for high-risk HPV during follow-up (median: 2.21 years; range: 0 to 5.42 years). The absolute infection rate of HPV was higher among women with a specialist diagnosis of mental disorder (HR = 1.45; 95% CI [1.34, 1.57]; p < 0.001) or a filled prescription of psychotropic medication (HR = 1.67; 95% CI [1.55, 1.79]; p < 0.001), compared to women without such. The increment in absolute infection rate was noted for depression, anxiety, stress-related disorder, substance-related disorder, and ADHD, and for use of antidepressants, anxiolytics, sedatives, and hypnotics, and was consistent across age groups. The main limitations included selection of the female population in Stockholm as they must have at least 1 negative test result of HPV, and relatively short follow-up as HPV-based screening was only introduced in 2014 in Stockholm. CONCLUSIONS: Mental illness is associated with an increased infection rate of high-risk HPV in women. Our findings motivate refined approaches to facilitate the WHO elimination agenda of cervical cancer among these marginalized women worldwide.

Occupation and tongue cancer in Nordic countries.

PURPOSE: Almost 200,000 tongue cancers were diagnosed worldwide in 2020. The aim of this study was to describe occupational risk variation in this malignancy. METHODS: The data are based on the Nordic Occupational Cancer (NOCCA) study containing 14.9 million people from the Nordic countries with 9020 tongue cancers diagnosed during 1961-2005. The standardized incidence ratio (SIR) of tongue cancer in each occupational category was calculated using national incidence rates as the reference. RESULTS: Among men, the incidence was statistically significantly elevated in waiters (SIR 4.36, 95% confidence interval (CI) 3.13--5.92), beverage workers (SIR 3.42, 95% CI 2.02-5.40), cooks and stewards (SIR 2.55, 95% CI 1.82-3.48), seamen (SIR 1.66, 95% CI 1.36-2.00), journalists (SIR 1.85, 95% CI 1.18-2.75), artistic workers (SIR 2.05, 95% CI 1.54-2.66), hairdressers (SIR 2.17, 95% CI 1.39-3.22), and economically inactive persons (SIR 1.57, 95% CI 1.42-1.73). Among women, the SIR was statistically significantly elevated only in waitresses (SIR 1.39, 95% CI 1.05-1.81). Statistically significant SIRs ≤ 0.63 were observed in male farmers, gardeners, forestry workers and teachers, and in female launderers. CONCLUSIONS: These findings may be related to consumption of alcohol and tobacco, but the effect of carcinogenic exposure from work cannot be excluded.

Impact of cervical screening by human papillomavirus genotype: Population-based estimations.

BACKGROUND: Cervical screening programs use testing for human papillomavirus (HPV) genotypes. Different HPV types differ greatly in prevalence and oncogenicity. We estimated the impact of cervical screening and follow-up for each HPV type. METHODS AND FINDINGS: For each type of HPV, we calculated the number of women needed to screen (NNS) and number of women needing follow-up (NNF) to detect or prevent one cervical cancer case, using the following individual level input data (i) screening and cancer data for all women aged 25 to 80 years, resident in Sweden during 2004 to 2011 (N = 3,568,938); (ii) HPV type-specific prevalences and screening histories among women with cervical cancer in Sweden in 2002 to 2011(N = 4,254); (iii) HPV 16/18/other HPV prevalences in the population-based HPV screening program (N = 656,607); and (iv) exact HPV genotyping in a population-based cohort (n = 12,527). Historical screening attendance was associated with a 72% reduction of cervical cancer incidence caused by HPV16 (71.6%, 95% confidence interval (CI) [69.1%, 73.9%]) and a 54% reduction of cancer caused by HPV18 (53.8%, 95% CI [40.6%, 63.1%]). One case of HPV16-caused cervical cancer could be prevented for every 5,527 women attending screening (number needed to screen, NNS). Prevention of one case of HPV16-caused cervical cancer required follow-up of 147 HPV16-positive women (number needed to follow-up, NNF). The NNS and NNF were up to 40 to 500 times higher for HPV types commonly screened for with lower oncogenic potential (HPV35,39,51,56,59,66,68). For women below 30 years of age, NNS and NNF for HPV16 were 4,747 and 289, respectively, but >220,000 and >16,000 for HPV35,39,51,56,59,66,68. All estimates were either age-standarized or age-stratified. The primary limitation of our study is that NNS is dependent on the HPV prevalence that can differ between populations and over time. However, it can readily be recalculated in other settings and monitored when HPV type-specific prevalence changes. Other limitations include that in some age groups, there was little data and extrapolations had to be made. Finally, there were very few cervical cancer cases associated with certain HPV types in young age group. CONCLUSIONS: In this study, we observed that the impact of cervical cancer screening varies depending on the HPV type screened for. Estimating and monitoring the impact of screening by HPV type can facilitate the design of effective and efficient HPV-based cervical screening programs. TRIAL REGISTRATION: ClinicalTrials.gov with numbers NCT00479375, NCT01511328.

HPV Vaccination and the Risk of Invasive Cervical Cancer.

BACKGROUND: The efficacy and effectiveness of the quadrivalent human papillomavirus (HPV) vaccine in preventing high-grade cervical lesions have been shown. However, data to inform the relationship between quadrivalent HPV vaccination and the subsequent risk of invasive cervical cancer are lacking. METHODS: We used nationwide Swedish demographic and health registers to follow an open population of 1,672,983 girls and women who were 10 to 30 years of age from 2006 through 2017. We assessed the association between HPV vaccination and the risk of invasive cervical cancer, controlling for age at follow-up, calendar year, county of residence, and parental characteristics, including education, household income, mother's country of birth, and maternal disease history. RESULTS: During the study period, we evaluated girls and women for cervical cancer until their 31st birthday. Cervical cancer was diagnosed in 19 women who had received the quadrivalent HPV vaccine and in 538 women who had not received the vaccine. The cumulative incidence of cervical cancer was 47 cases per 100,000 persons among women who had been vaccinated and 94 cases per 100,000 persons among those who had not been vaccinated. After adjustment for age at follow-up, the incidence rate ratio for the comparison of the vaccinated population with the unvaccinated population was 0.51 (95% confidence interval [CI], 0.32 to 0.82). After additional adjustment for other covariates, the incidence rate ratio was 0.37 (95% CI, 0.21 to 0.57). After adjustment for all covariates, the incidence rate ratio was 0.12 (95% CI, 0.00 to 0.34) among women who had been vaccinated before the age of 17 years and 0.47 (95% CI, 0.27 to 0.75) among women who had been vaccinated at the age of 17 to 30 years. CONCLUSIONS: Among Swedish girls and women 10 to 30 years old, quadrivalent HPV vaccination was associated with a substantially reduced risk of invasive cervical cancer at the population level. (Funded by the Swedish Foundation for Strategic Research and others.).

COVID-19 hospitalization outcomes in adults by HIV status; a nation-wide register-based study.

OBJECTIVES: To assess the outcome of patients hospitalized with COVID-19 by HIV status and risk factors for severe COVID-19 in people living with HIV (PWH), we performed a nationwide cohort study using register data. METHODS: All people aged ≥18 years hospitalized with a primary COVID-19 diagnosis (U07.1 or U07.2) in Sweden between February 2020 and October 2021 were included. The primary outcome was severe COVID-19 [intensive care unit (ICU) admission or 90-day mortality]. Secondary outcomes were days in hospital and ICU, complications in hospital, and risk factors for severe COVID-19 in PWH. Regression analyses were performed to assess severe COVID-19 by HIV status and risk factors. RESULTS: Data from 64 815 hospitalized patients were collected, of whom 121 were PWH (0.18%). PWH were younger (p < 0.001), and larger proportions were men (p = 0.014) and migrants (p < 0.001). Almost all PWH had undetectable HIV-RNA (93%) and high CD4 T-cell counts (median = 560 cells/µL, interquartile range: 376-780). In an unadjusted model, PWH had statistically significant lower odds of severe COVID-19 compared with patients without HIV [odds ratio (OR) = 0.6, 95% confidence interval (CI): 0.34-0.94], but there was no significant difference after adjusting for age and comorbidity (adjusted OR = 0.7, 95% CI: 0.43-1.26). A statistically significant lower proportion of PWH (8%, 95% CI: 5-15%) died within 90 days compared with those without HIV (16%, 95% CI: 15-16%, p = 0.024). There was no statistically significant difference in days in hospital and complications during the hospital stay between PWH and patients without HIV. CONCLUSIONS: In this nationwide study including well-treated PWH, HIV was not a risk factor in hospitalized patients for developing severe COVID-19.

Pregnancy Outcomes in Women With a Prior Cervical Intraepithelial Neoplasia Grade 3 Diagnosis : A Nationwide Population-Based Cohort Study With Sibling Comparison Design.

BACKGROUND: Treatment of cervical intraepithelial neoplasia grade 3 (CIN 3) removes or destroys part of the cervix and might subsequently influence pregnancy outcomes. OBJECTIVE: To investigate pregnancy outcomes in women diagnosed with CIN 3. DESIGN: Population- and sibling-matched cohort study. SETTING: Sweden, 1973 to 2018. PARTICIPANTS: The general population comparison included 78 450 singletons born to women diagnosed with CIN 3 and 784 500 matched singletons born to women in the general population who had no CIN 3 diagnosis; the sibling comparison included 23 199 singletons born to women diagnosed with CIN 3 and 28 135 singletons born to their sisters without a CIN 3 diagnosis. MEASUREMENTS: Preterm birth, including spontaneous or iatrogenic preterm birth; infection-related outcomes, including chorioamnionitis and infant sepsis; and early neonatal death, defined as death during the first week after birth. RESULTS: Compared with the matched general population, women previously diagnosed with CIN 3 were more likely to have a preterm birth, especially extremely preterm (22 to 28 weeks; odds ratio [OR], 3.00 [95% CI, 2.69 to 3.34]) or spontaneous preterm (OR, 2.12 [CI, 2.05 to 2.20]); infection-related outcomes, including chorioamnionitis (OR, 3.23 [CI, 2.89 to 3.62]) and infant sepsis (OR, 1.72 [CI, 1.60 to 1.86]); or early neonatal death (OR, 1.83 [CI, 1.61 to 2.09]). Sibling comparison analyses rendered largely similar results. Over time, the risk difference attenuated for all outcomes and disappeared for early neonatal death. LIMITATION: Lack of data on CIN 3 treatment and spontaneous abortion. CONCLUSION: History of CIN 3 is associated with adverse pregnancy outcomes even after accounting for familial factors. Decreasing risk estimates over time suggest that adverse pregnancy outcomes among women diagnosed with CIN 3 may be minimized by improving treatment methods. PRIMARY FUNDING SOURCE: The Swedish Research Council, the Swedish Cancer Society, and the Swedish Research Council for Health, Working Life and Welfare.

NSAID use and unnatural deaths after cancer diagnosis: a nationwide cohort study in Sweden.

BACKGROUND: Cancer patients experience increased risk of death from accident and suicide. Cognitive impairment induced by cancer-related inflammation and stress-related psychiatric symptoms may be underlying mechanisms. We therefore studied the association between use of nonsteroidal anti-inflammatory drugs (NSAIDs) and risk of these outcomes. METHODS: Following a cohort of 388,443 cancer patients diagnosed between October 2005 and December 2014 in Sweden, we ascertained dispense of aspirin or non-aspirin NSAIDs from 3 months before cancer diagnosis onward and defined the on-medication period as from date of drug dispense until the prescribed dosage was consumed. Follow-up time outside medicated periods and time from unexposed patients were defined as off-medication periods. We used Cox models to estimate hazard ratios (HRs) of death due to suicide or accident, by comparing the on-medication periods with off-medication periods. RESULTS: In total, 29.7% of the cancer patients had low-dose aspirin dispensed and 29.1% had non-aspirin NSAIDs dispensed. Patients with aspirin use were more likely to be male than patients without aspirin use. Compared with off-medication periods, there was a 22% lower risk of accidental death (N = 651; HR 0.78, 95% confidence interval [CI]: 0.70 to 0.87) during on-medication periods with aspirin. The use of aspirin was not associated with risk of suicide (N = 59; HR 0.96, 95% CI: 0.66 to 1.39). No association was noted between use of non-aspirin NSAIDs and the risk of suicide (N = 13; HR 0.95, 95% CI: 0.42 to 2.18) or accidental death (N = 59; HR 0.92, 95% CI: 0.68 to 1.26). CONCLUSIONS: Intake of low-dose aspirin after cancer diagnosis was associated with a lower risk of unnatural deaths among cancer patients.

Colposcopic performance in a birth cohort previously eligible for human papillomavirus vaccination.

BACKGROUND: Sweden started subsidized quadrivalent human papillomavirus vaccination for girls aged 13 to 17 in 2007. Since 2012, vaccination has been offered to all girls aged 10 to 12 within a school-based vaccination program, with a coverage of 80% or more. In addition, the vaccine has been offered on-demand as catch-up vaccination for girls aged 13 to 18, with a cumulative coverage of 55% to 60%. Since the first women in Sweden eligible for human papillomavirus vaccination entered the cervical screening program, questions on how to evaluate colposcopic findings among vaccinated women have arisen. Evidence is inconsistent on whether colposcopic features for the detection of cervical lesions are influenced by specific human papillomavirus genotypes and what role they can play in the prevention of invasive cervical cancer in vaccinated women. OBJECTIVE: The primary objective of the study was to compare colposcopic evaluation in vaccinated and unvaccinated women entering the organized cervical screening program. STUDY DESIGN: Women in the 1994 and 1995 birth cohorts who entered the cervical screening program at age 23 in 1 region in Sweden were identified. Colposcopy was performed within 2 to 4 months after a positive screening result in accordance with national guidelines. Colposcopic performance was evaluated according to national guidelines with the Swede score and colposcopic impression. Punch biopsies were taken from colposcopic lesions and as "random biopsies" in the absence of lesions. These biopsies were used as the gold standard for the analysis. An endocervical sample was analyzed for cytologic findings and detection of 14 high-risk human papillomavirus genotypes. All colposcopic imaging was saved digitally for re-review. Vaccination status was obtained through linkage to national vaccination registries. Results were compared between vaccinated and unvaccinated women. RESULTS: In 2018 and 2019, 160 out of 165 (98%) women with a positive screening result attended colposcopy, of which 90 (56%) were vaccinated and 70 (44%) were unvaccinated. Only 7 out of 90 (5%) women in the vaccinated group were human papillomavirus 16/18-positive, compared with 23 out of 70 (33%) in the unvaccinated group (P<.001). There was a total of 61 out of 160 (38%) women with high-grade lesions-33 out of 90 (37%) in the vaccinated group and 28 out of 70 (40%) in the unvaccinated group (P=.697). There was 64% (21/33) of vaccinated women and 75% (21/28) of unvaccinated women with high-grade squamous intraepithelial lesions who had a Swede score of 6 to 10 (indicating high-grade squamous intraepithelial lesions) (P=.124). The sensitivity was slightly higher for the detection of high-grade squamous intraepithelial lesions in unvaccinated women using both colposcopic tests (Swede score, 0.67 vs 0.75; colposcopic impression, 0.67 vs 0.68), but the difference was not statistically significant. CONCLUSION: We found no statistically significant difference between the colposcopic evaluation of vaccinated and unvaccinated women, although human papillomavirus vaccination reduced the prevalence of human papillomavirus 16/18 infection in human papillomavirus-vaccinated women. Our results indicate that colposcopic examination is still a useful tool in vaccinated women entering the organized cervical screening program.

Patterns of sexual behaviour associated with repeated chlamydia testing and infection in men and women: a latent class analysis.

BACKGROUND: Adolescents and young adults are at higher risk of acquiring Chlamydia trachomatis infection (chlamydia), so testing is promoted in these populations. Studies have shown that re-testing for chlamydia is common amongst them. We investigated how sexual risk behaviour profiles are associated with repeated testing for chlamydia. METHODS: We used baseline data from a cohort of 2814 individuals recruited at an urban STI -clinic. We applied latent class (LC) analysis using 9 manifest variables on sexual behaviour and substance use self-reported by the study participants. We fitted ordered logistic regression to investigate the association of LC membership with the outcomes repeated testing during the past 12 months and lifetime repeated testing for chlamydia. Models were fit separately for men and women. RESULTS: We identified four LCs for men and three LCs for women with increasing gradient of risky sexual behaviour. The two classes with the highest risk among men were associated with lifetime repeated testing for chlamydia: adjOR = 2.26 (95%CI: 1.50-3.40) and adjOR = 3.03 (95%CI: 1.93-4.74) as compared with the class with lowest risk. In women, the class with the highest risk was associated with increased odds of repeated lifetime testing (adjOR =1.85 (95%CI: 1.24-2.76)) and repeated testing during past 12 months (adjOR = 1.72 (95%CI: 1.16-2.54)). An association with chlamydia positive test at the time of the study and during the participant's lifetime was only found in the male highest risk classes. CONCLUSION: Prevention messages with regard to testing for chlamydia after unprotected sexual contact with new/casual partners seem to reach individuals in highest risk behaviour classes who are more likely to test repeatedly. Further prevention efforts should involve potentially more tailored sex-specific interventions taking into consideration risk behaviour patterns.

Differing Age-Specific Cervical Cancer Incidence Between Different Types of Human Papillomavirus: Implications for Predicting the Impact of Elimination Programs.

The elimination of cervical cancer rests on high efficacy of human papillomavirus (HPV) vaccines. The HPV type distribution among cases of invasive cervical cancer (ICC) is used to make predictions about the impact of eliminating different types of HPV, but accumulating evidence of differences in age-specific cancer incidence by HPV type exists. We used one of the largest population-based series of HPV genotyping of ICCs (n = 2,850; Sweden, 2002-2011) to estimate age-specific ICC incidence by HPV type and obtain estimates of the cancer-protective impact of the removal of different HPV types. In the base case, the age-specific ICC incidence had 2 peaks, and the standardized lifetime risk (SLTR, the lifetime number of cases per birth cohort of 100,000 females) for HPV-positive ICC was 651 per 100,000 female births. In the absence of vaccine types HPV 16 and HPV 18, the SLTR for ICC was reduced to 157 per 100,000 female births (24% of HPV-positive SLTR). Elimination of all 9 types that can currently be vaccinated against reduced the remaining SLTR to 47 per 100,000 female births (7%), the remaining ICC incidence only slowly increasing with age. In conclusion, after elimination of vaccine-protected HPV types, very few cases of ICC will be left, especially among fertile, reproductive-age women.

Changes in the Trend of Sexually Acquired Chlamydia Infections in Sweden and the Role of Testing: A Time Series Analysis.

BACKGROUND: We investigated the notification trends of sexually acquired chlamydia (chlamydia) and its association with testing in Sweden before (1992-2004) and after (2009-2018) the discovery of a new variant of Chlamydia trachomatis (nvCT). METHODS: We applied monthly time series analysis to study chlamydia trends and annual time series to study chlamydia rates adjusted for testing. We analyzed incidence nationally and by county group (based on able and unable to detect nvCT at time of discovery). RESULTS: We present data on 606,000 cases of chlamydia and 9.9 million persons tested. We found a U-shaped chlamydia trend during the period 1992-2004, with an overall increase of 83.7% from 1996 onward. The period 2009-2018 began with a stable trend at a high incidence level followed by a decrease of 19.7% during the period 2015-2018. Peaks were seen in autumn and through during winter and summer. Similar results were observed by groups of county, although with varying levels of increase and decrease in both periods. Furthermore, increased testing volume was associated with increased chlamydia rates during the first period (P = 0.019) but not the second period. CONCLUSIONS: Our results showed that chlamydia trends during the period 2009-2018 were not driven by testing, as they were during the period 1992-2004. This suggests less biased notified chlamydia rates and thus possibly a true decrease in chlamydia incidence rates. It is important to adjust case rates for testing intensity, and future research should target other potential factors influencing chlamydia rates.

Cancer incidence among musicians: 45 years of follow-up in four Nordic countries.

BACKGROUND: There are studies suggesting that participation in musical activities may protect from cancer. On the other hand, some musicians have a lifestyle that might increase the risk of cancer. The objective of this study was to assess the cancer pattern of musicians in four Nordic countries. MATERIAL AND METHODS: This study combines census and cancer registry data from 1961 to 2005 for 13 million people from Finland, Iceland, Norway, and Sweden. Standardized incidence ratio (SIR) analyses were conducted with the cancer incidence rates for entire national populations used as reference rates. RESULTS: There were 11,401 male and 3105 female musicians with 2039 cancer cases. The SIR for all sites combined was 1.02 (95% confidence interval 0.97-1.07) in men and 1.04 (0.94-1.15) in women. In male musicians, there were statistically significant excesses in oropharyngeal cancer (4.36, 2.73-6.60), esophageal cancer (2.08, 1.51-2.81), liver cancer (1.81, 1.26-2.52), and skin melanoma (1.40, 1.10-1.75). The risk was decreased in lip cancer (0.13, 0.02-0.48), stomach cancer (0.66, 0.50-0.82), and lung cancer (0.77, 0.65-0.90). In female musicians, there were no statistically significant SIRs in any of the cancer types studied, but the risk of breast cancer was significantly elevated in the age category of 70+ (1.52, 1.04-2.15). The overall SIR was stable over the 45 year period of observation, but strong decreases were observed in the SIRs of esophageal cancer, liver cancer, laryngeal cancer, and skin melanoma. CONCLUSION: Musicians have characteristics of indoor workers such as low incidence of lip cancer and high incidence of skin melanoma. The low incidence of lung cancer suggests that the prevalence of smoking among musicians is lower than in the general population while the elevated risk of alcohol-related cancer types suggest that drinking is likely more common among musicians. The cancer risk for all sites combined is still similar to that of the general population in the four countries studied.

Healthcare-Associated Legionnaires' Disease, Europe, 2008-2017.

Healthcare-associated Legionnaires' disease (HCA LD) can cause nosocomial outbreaks with high death rates. We compared community-acquired LD cases with HCA LD cases in Europe during 2008-2017 using data from The European Surveillance System. A total of 29 countries reported 40,411 community-acquired and 4,315 HCA LD cases. Of the HCA LD cases, 2,937 (68.1%) were hospital-acquired and 1,378 (31.9%) were linked to other healthcare facilities. The odds of having HCA LD were higher for women, children and persons <20 years of age, and persons >60 years of age. Out of the cases caused by Legionella pneumophila with a known serotype, community-acquired LD was more likely to be caused by L. pneumophila serogroup 1 (92.3%) than was HCA LD (85.1%). HCA LD patients were more likely to die. HCA LD is associated with specific patient demographics, causative strains, and outcomes. Healthcare facilities should consider these characteristics when designing HCA LD prevention strategies.

Cervical cancer case-control audit: Results from routine evaluation of a nationwide cervical screening program.

Our study used a refined case-control cervical cancer Audit framework to investigate effectiveness of cervical screening, with measures of three screening failures: irregular-participation, cervical cancer developed after cytological abnormalities and after normal screening results. The register-based study included 4,254 cervical cancer cases diagnosed in Sweden during 2002-2011, and 30 population-based controls per case. We used conditional logistic regression models to examine relative risks of cervical cancer in relation to screening participation and screening results in the past two screening rounds from 6 months before cancer diagnosis. We found that women unscreened in past two screening rounds showed four times increased risk of cervical cancer compared to women screened in time (OR = 4.1, 95% CI = 3.8-4.5), and women unscreened in the previous round but screened in the most recent round also showed a statistically significantly elevated risk (OR = 1.6, 95% CI = 1.5-1.8). Women having abnormality in previous two rounds exhibited higher risk of cervical cancer compared to women screened with normal results, while having normal results in the subsequent round after the abnormality also yielded an increased risk (OR = 4.0, 95% CI = 3.2-5.1). Being screened with only normal results was associated with 89% risk reduction for squamous cell cancer, compared to women unscreened, but only 60% reduction for adenocarcinoma. Our findings emphasize the importance of routine participation in cervical screening and suggest that management of abnormalities, as well as sensitivity of the test, warrants improvement especially for preventing cervical adenocarcinoma. The Audit framework serves as routine evaluation model and the findings benchmark for future evaluation of changes in screening practice.

Impact of HPV vaccination on cervical screening performance: a population-based cohort study.

BACKGROUND: Human papillomavirus (HPV) vaccination is predicted to lower the positive predictive value (PPV) of cytology. METHODS: We included 153,250 girls born between 1989 and 1993, resident in Sweden since the introduction of HPV vaccines (October 2006) and attending cervical screening at age 23 years. We assessed their first cytology and following histopathological diagnosis using Swedish National Cervical Screening Registry (NKCx). By linkage with the national Swedish HPV vaccination registry, we determined PPV of abnormal cytology for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and the differences with 95% confidence intervals (CIs) according to vaccination status. RESULTS: The PPV of high-grade cytology for CIN2+ was 69.9% (95% CI, 67.9-71.9), 64.9% (95% CI, 59.8-69.8) and 57.4% (95% CI, 50.9-63.7) among women unvaccinated, initiating vaccination at age 17-22 years and initiating vaccination before age 17 years, corresponding to reduction in PPV by 8% (95% CI, 0-15%) and 17% (95% CI, 7-26%) in vaccinated groups after adjustment for birth cohort, respectively. CONCLUSION: The PPV of cytology for CIN2+ decreased among vaccinated women, and the decrease was stronger for girls vaccinated at younger ages. A switch from cytology to HPV testing might potentially improve the screening performance.

Deep sequencing detects human papillomavirus (HPV) in cervical cancers negative for HPV by PCR.

BACKGROUND: Human papillomavirus (HPV) is a necessary cause of cervical cancer, although some invasive cervical cancers may test negative by HPV PCR. We previously requested all invasive cervical cancers in Sweden during 10 years and subjected them to PCR. We also optimised methods for deep sequencing of formalin-fixed paraffin-embedded samples. METHODS: Using Novaseq 6000, we simultaneously sequenced total DNA and cDNA from 392 HPV PCR-negative cervical cancers. Non-human reads were queried against all known HPVs. The complete database now contains PCR and/or deep sequencing data on 2850 invasive cervical cancers. RESULTS: HPV sequences were detected in 169/392 of HPV PCR-negative cervical cancers. Overall, 30 different HPV types were detected, but only 5 types were present in proportions above 3% of cancers. More than 92% of tumours were HPV-positive in PCR and/or sequencing (95% confidence interval: 91.1-93.1%). Exploring possible reasons for failure to previously detect HPV suggest that more sensitive type-specific PCRs for HPV 31, 33, 45 and 73 targeting retained regions of HPV would have detected most of these (117/392). CONCLUSIONS: Unbiased deep sequencing provides comprehensive data on HPV types in cervical cancers and appears to be an important tool for quality assurance of HPV screening.

Sequencing detects human papillomavirus in some apparently HPV-negative invasive cervical cancers.

Introduction. Cervical cancer is caused by human papillomavirus (HPV), but some cases may test HPV-negative. We previously tested 2850 Swedish cases and found that 394/2850 (13.8 %) cases tested HPV DNA-negative by PCR. Sequencing is the most thorough method to assess HPV status.Aim. We wished to assess whether deep sequencing might detect HPV sequences among these HPV-negative cervical cancer specimens, and to increase the likelihood of detecting transcriptionally active infections.Methodology. Out of the 2850 cancer cases, we sequenced a random sample of 92 HPV PCR-negative cervical cancers and 34 HPV PCR-positive cervical cancers. Four pools of blank blocks were sequenced as negative controls. To enrich for mRNA - a hallmark of active viral infection - the samples were extracted, reverse-transcribed, rRNA-depleted and then sequenced using the NovaSeq 6000 system (Illumina, USA). High-quality reads were aligned to the human genome and non-human reads were queried against HPV proteins.Results. We obtained a median of 23 million paired reads per sample. HPV was detected in 31/34 HPV PCR-positive cases. Among cases negative for HPV by PCR, 48/92 (52.2 %) contained HPV sequences, with HPV33 being the most commonly detected type among these (14/48 cases, 29.2 %). Comparison of the ratio of exon and intron sequences found that the sequenced material contained both DNA and RNA. Splice junctions were detected in 12 cases.Conclusion. Apparently, some cervical cancers contain HPV that is difficult to detect by PCR. Sequencing may be a helpful tool for additional quality assurance for HPV testing methods.

Increase of cervical cancer incidence in Sweden in relation to screening history: population cohort study.

Background: Cervical cancer incidence in Sweden decreased from 24/100,000 in 1965 to 8/100,000 in 2011, but has from 2014 increased to 11/100,000. The increase appears to correlate to screening history. We perform a study of the cancer risk change in relation to screening history over two screening rounds to verify the correlation.Material and methods: We studied the cohorts of all 3,047,850 individual women living in Sweden in each year from 2002-2015. Registry linkages between the Total Population Register, the Swedish National Cervical Screening Registry, the Swedish Cervical Cancer Audit database and the National Quality Register for Gynecological Cancer, defined the incidence rates of invasive cervical cancer comparing time periods 2002-2013 to 2014-2015, in women whose screening history in 2 screening intervals prior to each year were either (i) adequately screened with normal results (almost exclusively cytology, 52% of the population) or (ii) unscreened (13% of the population). We also investigated the incidence increase by time since a normal smear performed in 2002-2012.Results: Among women adequately screened with normal results there was a strong incidence increase in 2014-2015 compared to previous years (Incidence rate ratio (IRR) = 1.59, 95%CI = 1.36-1.85), but no significant increase among unscreened women (IRR = 1.09, 95%CI = 0.94-1.27). There was no increase in incidence 0-2.5 years after a normal smear over the study period (IRR = 1.04, 95% CI = 0.88-1.24), but a strong increase 3-4 years after a normal smear since year 2009 (IRR = 1.52, 95% CI = 1.25-1.84).Conclusion: The results suggest that the overall increase is associated with an increased cancer risk in women adequately screened with normal cytological results. Possibly, precursor lesions missed in one screening round might result in detection of early stage invasive cancer in the subsequent screening.

Smoking-adjusted risk of kidney cancer by occupation: a population-based cohort study of Nordic men.

Background: Evidence suggests that among some occupational groups, there is an elevated risk of kidney cancer. This might, however, derive from a difference in smoking habits across occupational groups. The objective of this study was to determine smoking-adjusted occupational variation in the incidence of kidney cancer in Nordic males.Material and Methods: The source population for this study consisted of 7.4 million men from Denmark, Iceland, Finland, Norway, and Sweden. Data on occupation were obtained from national censuses conducted in the years 1960-1990. Data on cancer cases came from national cancer registries. A proxy for the occupation-specific smoking prevalence among all Nordic men was calculated based on the occupation-specific smoking prevalence and lung cancer incidence data for Finnish men. Smoking-adjusted standardized incidence ratio (SIRadj) with 95% confidence intervals (95%CI) were calculated for each occupational group.Results: The highest SIRadj estimates were observed in dentists (1.32, 95%CI 1.06-1.62), journalists (1.20, 95%CI 1.00-1.42), physicians (1.19, 95%CI 1.03-1.36), public safety workers (1.18, 95%CI 1.10-1.26), administrators (1.17, 95%CI 1.13-1.22), military personnel (1.16, 95%CI 1.05-1.28), and religious workers (1.17, 95%CI 1.09-1.26). The lowest SIRadj was observed among forestry workers (0.82, 95%CI 0.76-0.88).Conclusions: Tobacco smoking plays an important role in the occupational variation in the risk of kidney cancer. The smoking-adjusted incidence of kidney cancer was increased in dentists, physicians, journalists, administrators, and public safety workers.