Pär Sparén

Risk of Injuries around Diagnosis of Cervical Cancer and Its Precursor Lesions: A Nationwide Cohort Study in Sweden

Abstract Background: Highly increased risk of injuries has been noted around the time of cancer diagnosis. Whether there is a similar increase in risk around the diagnosis of cervical cancer and its precursor lesions was unknown. Methods: We performed a cohort study including 3,016,307 Swedish women that participated in cervical screening during 2001 to 2012. We calculated the incidence rates (IR) of hospitalized iatrogenic or noniatrogenic injuries during the diagnostic workup, and the time interval from smear or punch biopsy until surgical treatment or 2 months after the last smear or biopsy, among women with invasive cervical cancer (ICC) or its precursor lesions. We calculated the IRs of injuries during the 2 months after a normal smear among the other women as reference. IR ratios (IRR) and 95% confidence intervals (CI) were calculated using Poisson regression. Results: Compared with other women, there was an increased rate of iatrogenic injuries during the diagnostic workup of women with ICC (IR, 0.58 per 1,000 person-months; IRR, 8.55; 95% CI, 3.69–19.80) as well as of women with cervical intraepithelial neoplasia grade 3 and adenocarcinoma in situ (IR, 0.09 per 1,000 person-months; IRR, 3.04; 95% CI, 1.73–5.34). We also found an increased rate of noniatrogenic injuries during the diagnostic workup of women with invasive cancer (IR, 0.65 per 1,000 person-months; IRR, 2.48; 95% CI, 1.30–4.47). Conclusions: Although rare, there was an increased risk of inpatient care for iatrogenic and noniatrogenic injuries during the diagnostic workup of women with ICC. Impact: Women experienced burden of medical complications and psychologic distress around diagnosis of a potential cervical cancer.

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

Abstract 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.

HPV Types in Cervical Precancer by HIV Status and Birth Region: A Population-Based Register Study

Abstract Background: Data are lacking regarding which human papillomavirus (HPV) types cause high-grade cervical neoplasia (CIN2+) in people with HIV in Europe. We assessed which HPV types are associated with CIN2+ in women living in Sweden by HIV status. Methods: The Swedish National HIV Registry, the Swedish Population Registry, and the Swedish National Cervical Screening Registry were linked. CIN2+ tissue blocks of 130 women living with HIV (WLWH) and 234 HIV-negative women, matched for country of birth (1:2), were retrieved from bio-banks and HPV genotyped. Adjusted ORs (adjOR), stratified by country of birth, were calculated using conditional logistic regression. Matching was broken for cross-group comparisons. Results: WLWH with CIN2 were less likely to have HPV16 [14% vs. 40%; adjOR 0.1; 95% confidence interval (CI), 0.04–0.56] than HIV-negative women, but among women with CIN3, there was no difference in HPV16 prevalence by HIV status (adjOR 0.9; 95% CI, 0.51–1.70). WLWH were six times more likely to have HPV35 in CIN3 than HIV-negative women (adjOR 6.2; 95% CI, 1.3–30.4). WLWH from sub-Saharan Africa (SSA) had less 9-valent vaccine types, compared with both HIV-negative women born in Sweden (adjOR 0.1; 95% CI, 0.02–0.44) and WLWH born in Sweden (adjOR 0.1; 95% CI, 0.01–0.73), mostly because of decreased HPV16 and increased HPV35. Conclusions: WLWH from SSA were less likely to be covered by the 9-valent vaccine, mostly due to less HPV16 and more HPV35. Impact: This could have implications for HPV vaccines, currently not including HPV35, and for HPV-screening algorithms in women with origin from SSA.

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

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.

Pregnancy Outcomes in Women With a Prior Cervical Intraepithelial Neoplasia Grade 3 Diagnosis

Treatment of cervical intraepithelial neoplasia grade 3 (CIN 3) removes or destroys part of the cervix and might subsequently influence pregnancy outcomes. To investigate pregnancy outcomes in women diagnosed with CIN 3. Population- and sibling-matched cohort study. Sweden, 1973 to 2018. 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. 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. 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. Lack of data on CIN 3 treatment and spontaneous abortion. 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. The Swedish Research Council, the Swedish Cancer Society, and the Swedish Research Council for Health, Working Life and Welfare.

Human Papillomavirus Infection Determines Prognosis in Cervical Cancer

PURPOSE Detection of human papillomavirus (HPV) by polymerase chain reaction in invasive cervical cancer is strongly associated with prognosis but previous studies have not considered sequencing efforts. We aimed to assess the association when also including comprehensive analysis of HPV infection by deep sequencing and a longer follow-up period. MATERIALS AND METHODS We subjected all 392 of 2,845 invasive cervical cancer cases that were polymerase chain reaction–negative for HPV to RNA sequencing on the NovaSeq 6000 platform (Illumina) and identified an additional 169 cases as HPV-positive. We followed all women from date of diagnosis to December 31, 2016, emigration, or death, whichever occurred first. The main outcome was all-cause mortality by December 31, 2016. We calculated 5-year cumulative relative survival ratios compared with the female general population and used Poisson regression to estimate excess hazard ratios of all-cause mortality by infection with any of the 13 most oncogenic (high-risk [hr]) HPV types in the tumor. All models were adjusted for age, time since diagnosis, stage, histology, and education level. RESULTS The 5-year cumulative relative survival ratio was 0.45 (95% CI, 0.39 to 0.51) in the hrHPV-negative group, and 0.74 (95% CI, 0.72 to 0.75) in the hrHPV-positive group. This translated to a statistically significantly 43% lower excess mortality in the hrHPV-positive group compared with the hrHPV-negative (corresponding to an excess hazard ratio 0.57; 95% CI, 0.48 to 0.69). There was no association between HPV risk group, clade, or number of HPV infections and prognosis. CONCLUSION hrHPV status is a strong determinant of cervical cancer prognosis over 15 years after diagnosis, above and beyond other established factors.

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.