Prediagnostic use of menopausal hormone therapy and long-term survival of localized epithelial ovarian cancer: The Extreme study

Use of menopausal hormone therapy (MHT) prior to an epithelial ovarian cancer (EOC) diagnosis has been suggested to be associated with improved survival. In a recent nationwide cohort study, we found that prediagnostic long-term MHT use, especially estrogen therapy (ET), was associated with improved long-term survival in women with nonlocalized EOC. Our aim was to investigate the influence of prediagnostic MHT use on long-term survival among women with localized EOC in the same nationwide study. Our study cohort comprised all women aged 50 years or older with an EOC diagnosis in Denmark 2000-2014 (n = 2097) identified from the Extreme study. We collected information on usage of systemic ET and estrogen plus progestin therapy (EPT) from the Danish National Prescription Registry. By using pseudo-values, 5- and 10-year absolute and relative survival probabilities were estimated with 95% confidence intervals (CIs) while adjusting for histology, comorbidity, and income. Relative survival probabilities >1 indicate better survival. The 5-year absolute survival probabilities were 61% and 56%, respectively, among women who were nonusers and users of prediagnostic MHT, whereas these numbers were 46% and 41%, respectively, regarding 10-year survival. Use of MHT was not significantly associated with an improved 5- or 10-year survival in women with localized EOC (5-year relative survival probability = 0.95, 95% CI: 0.89-1.02; 10-year relative survival probability = 0.92, 95% CI: 0.84-1.02). Similar findings were seen for systemic ET or EPT use. Our findings do not suggest a positive benefit from prediagnostic MHT use on long-term survival of localized EOC.

Low-dose aspirin use and risk of ovarian cancer: a combined analysis from two nationwide studies in Denmark and Sweden

BACKGROUND

Studies on association between low-dose aspirin use and ovarian cancer risk were mostly based on self-reported medication use and few had large enough sample size to investigate the potential modification effect by ovarian cancer risk factors.

METHODS

In these two nationwide nested case-control studies among the Danish and Swedish female population, 11,874 women with ovarian cancer (30-84 years old) (Denmark: 7328 diagnosed in 2000-2019, Sweden: 4546 diagnosed in 2010-2018) were randomly age- matched with 473,960 female controls (293,120 from Denmark, and 181,840 from Sweden). We used conditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) and combined the estimates based the fixed-effect assumption. Effect modification by inflammation-related risk factors and by indication (cardiovascular disease, CVD) were also investigated.

RESULTS

Ever use of low-dose aspirin was not strongly associated with the overall risk of ovarian cancer (OR = 0.97; 95%CI: 0.92-1.03). However, the association differed according to parity (nulliparous: OR = 0.80, 95%CI: 0.70-0.92; parous: OR = 1.00, 95%CI: 0.94-1.07; p-interaction = 0.0024), and according to history of CVD (no CVD: OR = 0.91, 95%CI: 0.82-1.00; ever CVD: OR = 1.05, 95%CI: 0.97-1.13; p-interaction =0.0204).

CONCLUSIONS

Low-dose aspirin use was associated with a decreased ovarian cancer risk especially in nulliparous women and in women without CVD diagnosis.

Antidepressant use and ovarian cancer risk: Evidence from nationwide studies with >14,000 cases from Denmark and Sweden

OBJECTIVE

Given that the evidence regarding the link between antidepressant use and ovarian cancer risk is equivocal, we investigated this research question by conducting two nationwide nested case-control studies among the Danish and Swedish populations.

METHODS

Altogether, 14,121 women with epithelial ovarian cancer (30-84 years old) (Denmark: 8976 diagnosed 2000-2019, Sweden: 5145 diagnosed 2010-2018) were randomly age-matched with 564,840 female controls (359,040 from Denmark, and 205,800 from Sweden) using risk set sampling. We used conditional logistic regression to estimate odds ratios (OR) with 95 % confidence intervals (CI) and combined the estimates based on the fixed-effect assumption. We also investigated potential effect modification by well-established risk factors for ovarian cancer.

RESULTS

Antidepressant use was associated with an overall reduced risk of ovarian cancer (OR = 0.92, 95%CI: 0.88-0.96), and that reduction was more pronounced in postmenopausal women and long-term users. The effect was most pronounced for serous ovarian tumors (OR = 0.90, 95%CI: 0.86-0.95) but was also observed in other subtypes, although not statistically significant. Among different types of antidepressants, selective serotonin reuptake inhibitors in general and citalopram in particular exhibited a noteworthy reduction in ovarian cancer risk (OR = 0.89, 95%CI: 0.82-0.96). Additionally, use of oral contraceptives and hormone replacement therapy individually modified the association between antidepressant use and ovarian cancer risk.

CONCLUSIONS

Use of an antidepressant was associated with a slight, but statistically significant, decrease in ovarian cancer risk. Given the morbidity and mortality associated with ovarian cancer, and increasing use of antidepressants, these findings may be of significance to cancer prevention and should be studied in more detail mechanistically.

PD-L1 expression in vulvar cancer: a systematic review and meta-analysis

Programmed cell death ligand-1 (PD-L1) expression in cancer may predict clinical response to immunotherapeutic treatment with PD-1/PD-L1 inhibitors. Within the vulvar cancer field, PD-L1 expression has only been assessed by a few studies. We conducted a meta-analysis to examine the prevalence of PD-L1 positivity in vulvar cancer. PubMed, Embase, and Cochrane were searched for articles reporting on PD-L1 expression in vulvar cancer. Study selection and data extraction were performed independently by two authors. We extracted data on PD-L1 prevalence in vulvar cancer according to combined positive score (CPS) and tumour proportion score (TPS). Cutoff values for positivity were ≥1 or ≥10 for CPS and ≥1% and ≥5% for TPS. Random-effects models were used to estimate pooled PD-L1 prevalence, with 95% confidence intervals (CIs). Tests of between-study heterogeneity were evaluated by the I2 statistics. Sources of heterogeneity were explored by subgroup analyses and meta-regression. In total, 19 studies were included. Pooled PD-L1 prevalence in vulvar cancer was 83.4% (95% CI: 70.8-91.3; I2  = 80.0) and 53.9% (95% CI: 37.4-69.6; I2  = 93.0) according to CPS and TPS, respectively. Based on TPS, human papillomavirus (HPV)-associated vulvar squamous cell carcinomas (SCC) showed a lower PD-L1 prevalence (39.9%; 95% CI: 13.3-74.2) compared with HPV-independent SCC (62.6%; 95% CI: 33.7-84.6), but meta-regression showed no significant variation in PD-L1 prevalence by HPV status. PD-L1 prevalence was similar in advanced (44.9%; 95% CI: 29.8-61.1) and localized vulvar cancer (56.7%; 95% CI: 18.9-76.7). In conclusion, PD-L1 expression in vulvar cancer is frequent but between-study heterogeneity was high. Based on a subgroup of heterogenous studies, we found no strong variation in PD-L1 prevalence according to HPV status and stage.

Biopsy-verified vulvar lichen sclerosus: Incidence trends 1997-2022 and increased risk of vulvar squamous precancer and squamous cell carcinoma

Population-based data on the epidemiology of vulvar lichen sclerosus (LS) are sparse and only few prospective studies have investigated the malignant potential of the disease. We used the nationwide Danish Pathology Registry to first assess the incidence of biopsy-verified vulvar LS in the period 1997-2022 and second to examine the incidence of vulvar high-grade squamous precancer and squamous cell carcinoma (SCC) in women with biopsy-verified vulvar LS (1978-2019) compared with that expected in the general female population. For the latter aim, we computed standardized incidence ratios (SIRs) with 95% confidence intervals (CIs). During our study period, the age-standardized incidence rate of vulvar LS increased from 5.0 (1997-1998) to 35.7 (2021-2022) per 100,000 person-years. Compared with the general female population, women with biopsy-verified vulvar LS had significantly increased rates of vulvar high-grade squamous precancer (SIR = 8.5; 95% CI: 7.2-10.0) and SCC (SIR = 16.2; 95% CI: 14.2-18.4). The SIRs of vulvar high-grade squamous precancer and SCC did not vary substantially according to length of follow-up. This nationwide and population-based study shows a 7-fold increase in the incidence of biopsy-verified vulvar LS since 1997. Data also show that women with biopsy-verified vulvar LS have 8.5 and 16 times higher than expected incidence of vulvar high-grade squamous precancer and SCC, respectively. The substantially increased incidence of vulvar high-grade squamous precancer and SCC following LS is important in relation to the clinical management and follow-up of LS patients.

History of autoimmune disease and long-term survival of epithelial ovarian cancer: The extreme study

OBJECTIVE

Patients with autoimmune disease may have impaired cancer survival. The aim was to investigate the association between autoimmune disease and ovarian cancer survival.

METHODS

From the Extreme study, we included women diagnosed with epithelial ovarian cancer (EOC) in Denmark during 1990-2014 (n = 11,870). Information on exposure and covariates was retrieved from nationwide registries. Using pseudo-values, we estimated absolute and relative 5- and 10-year survival probabilities with 95% confidence intervals (CIs) for autoimmune diseases combined and for the four most common individual disorders in our study population, namely type 1 diabetes, rheumatoid arthritis, Graves' disease, and inflammatory bowel disease.

RESULTS

The overall 5- and 10-year absolute survival probabilities were 35% and 24%, respectively, in women with EOC without autoimmune disease. Autoimmune diseases combined was not significantly associated with survival among women with EOC (5-year adjusted relative survival probability = 1.01, 95% CI: 0.94-1.09; 10-year adjusted relative survival probability = 0.90, 95% CI: 0.81-1.00). However, stratification by disease stage showed an impaired 10-year survival in women with autoimmune disease and a localized EOC (relative survival probability = 0.86, 95% CI: 0.76-0.97). None of the individual autoimmune diseases were statistically significantly associated with EOC survival.

CONCLUSIONS

Only among women with localized EOC, there seemed to be a long-term survival loss associated with a history of autoimmune disease. In contrast, no significant association between a history of autoimmune disease and survival was observed in women with nonlocalized EOC where the survival is already low.

Human papillomavirus vaccination and anal high-grade precancerous lesions and cancer-a real-world effectiveness study

BACKGROUND

Human papillomavirus (HPV) vaccination has shown high efficacy against anal HPV infection and lesions in clinical trials, and the HPV prevalence and type distribution in anal precancers and cancer predict a high preventable potential for HPV vaccination. However, the real-world effectiveness of HPV vaccination against anal high-grade lesions and cancer is yet to be shown.

METHODS

We investigated HPV vaccine effectiveness against anal high-grade squamous intraepithelial lesion (HSIL) or worse in a nationwide cohort including all Danish women aged 17-32 years during October 2006 to December 2021 (n = 968 881). HPV vaccinations and first occurrence of anal HSIL or worse were retrieved from nationwide registries. Women were considered vaccinated after first dose and classified by age at vaccination. Using Cox regression, hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for anal HSIL or worse according to vaccination status.

RESULTS

During follow-up, the number of incident histological anal HSIL or worse cases was 37 in unvaccinated women, and less than 5 and 26 in women vaccinated at ages younger than 17 years and 17-32 years, respectively. The overall number of cancers was less than 5. Compared with unvaccinated women, the risk of histological anal HSIL or worse was reduced for women vaccinated at age younger than 17 years (HR = 0.30, 95% CI = 0.10 to 0.87). For women vaccinated at age 17-32 years, the hazard rate of anal HSIL or worse was 1.21 (95% CI = 0.73 to 2.03).

CONCLUSION

This is the first study to demonstrate that HPV vaccination at a younger age is associated with substantially reduced risk of anal HSIL or worse in the general population.

Paracetamol use and risk of epithelial ovarian cancer: A nationwide nested case-control study

OBJECTIVE

To investigate whether paracetamol use is associated with a reduced risk of epithelial ovarian cancer (EOC).

DESIGN

A nationwide nested case-control study.

SETTING

Danish female population.

POPULATION

A total of 9589 EOC cases diagnosed from 2000 to 2019 were age-matched with 383 549 randomly selected female controls using risk set sampling.

METHODS

Paracetamol use, reproductive history, history of medication and history of surgery were retrieved from Danish national registers. Paracetamol use was defined as at least two prescriptions for up to 1 year before the index date, and was further classified according to recency, duration, cumulative dose and intensity of dose.

MAIN OUTCOME MEASURES

Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals for the association between paracetamol and EOC risk, overall and by histological subtypes.

RESULTS

'Ever' use of paracetamol was associated with a reduced EOC risk after adjusting for potential confounding factors (OR 0.92, 95% CI 0.87-0.97). The association was only significant among recent users (OR 0.89, 95% CI 0.84-0.95). The risk declined further with the increasing level of cumulative dose and intensity; women from the group with a high cumulative dose and a high intensity had a 13% (OR 0.87, 95% CI 0.80-0.94) and 14% (OR 0.86, 95% CI 0.79-0.93) reduced risk, respectively. In the histological subtype analysis, reduced risk with 'ever' use was most pronounced for serous and clear cell tumours.

CONCLUSIONS

Paracetamol use was associated with a decreased risk of EOC in a dose-response manner. Future studies are needed to validate the findings and investigate the mechanisms behind the association.

Risk of ovarian cancer after salpingectomy and tubal ligation: Prospects on histology and time since the procedure

OBJECTIVE

Recent theories propose that most epithelial ovarian cancer (EOC), depending on histological type, originate from other gynecological tissues and involve the ovary secondarily. According to these theories, any protective effect of salpingectomy and tubal ligation may vary by histological type. The study aim was to examine the association between salpingectomy and tubal ligation, respectively, and risk of EOC, with a focus on associations specific for histological types.

METHODS

We identified EOC cases and matching controls in national registries and gathered information on surgical procedures and potential confounders. Conditional logistic regression was used to estimate odds ratio (OR) with 95% confidence interval (CI) of EOC related to salpingectomy and tubal ligation, respectively, overall and stratified by histological type. Furthermore, we investigated the association according to timing of the procedures.

RESULTS

Our study comprised 16,822 EOC cases. Each case was matched with 40 controls. There was an overall EOC risk reduction after unilateral (OR = 0.73; 95% CI: 0.60-0.87) and bilateral salpingectomy (OR = 0.46; 95% CI: 0.31-0.67). A slight risk reduction was seen among women with previous tubal ligation (OR = 0.91; 95% CI: 0.83-0.99). For salpingectomy, the risk reduction increased with increasing time since the surgical procedure and was only present among women younger than 50 years at salpingectomy. Unilateral and bilateral salpingectomy was associated with a risk reduction for most histological types.

CONCLUSION

The association between previous salpingectomy and reduced risk of several histological subtypes of EOC supports the suggested theories about the site of origin of EOC and may be of clinical importance.

Hysterectomy and risk of epithelial ovarian cancer by histologic type, endometriosis, and menopausal hormone therapy

BACKGROUND

This nationwide, register-based case-control study investigated the association between hysterectomy and risk of epithelial ovarian cancer according to histology and by history of endometriosis and menopausal hormone therapy (MHT) use.

METHODS

From the Danish Cancer Registry, all women registered with epithelial ovarian cancer at age 40-79 years during 1998-2016 were identified (n = 6738). Each case was sex- and age-matched to 15 population controls using risk-set sampling. Information on previous hysterectomy on benign indication and potential confounders was retrieved from nationwide registers. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between hysterectomy and ovarian cancer according to histology, endometriosis, and use of MHT.

RESULTS

Hysterectomy was not associated with risk of epithelial ovarian cancer overall (OR=0.99; 95% CI 0.91 -1.09) but was associated with reduced risk of clear cell ovarian cancer (OR=0.46; 95% CI 0.28-0.78). In stratified analyses, decreased ORs associated with hysterectomy were seen in women with endometriosis (OR=0.74; 95% CI 0.50-1.10) and in non-users of MHT (OR=0.87; 95% CI 0.76-1.01). In contrast, among long-term MHT users, hysterectomy was associated with increased odds for ovarian cancer (OR=1.20; 95% CI 1.03-1.39).

CONCLUSION

Hysterectomy was not associated with epithelial ovarian cancer overall but with reduced risk of clear cell ovarian cancer. Our findings may suggest a reduced risk of ovarian cancer after hysterectomy in women with endometriosis and in MHT non-users. Interestingly our data pointed to an increased ovarian cancer risk associated with hysterectomy among long-term users of MHT.

Risk of nonovarian cancer in a nationwide-based study of nearly 5000 women with borderline ovarian tumors in Denmark

Evidence regarding cancer risk after borderline ovarian tumors (BOTs) is limited. We conducted a nationwide cohort study examining the incidence of nonovarian cancers in women with serous or mucinous BOTs compared with the general female population with up to 41 years of follow-up. Through the nationwide Pathology Registry, we identified nearly 5000 women with BOTs (2506 serous and 2493 mucinous) in Denmark, 1978 to 2018. We computed standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) as relative risk estimates of specific nonovarian cancers. Compared with general female population rates, women with serous BOTs had increased rates of particularly malignant melanoma (SIR = 1.9; 95% CI: 1.3-2.6), thyroid cancer (SIR = 3.0; 95% CI: 1.4-5.4) and myeloid leukemia (SIR = 3.2; 95% CI: 1.5-5.8), and women with mucinous BOTs had elevated rates of lung cancer (SIR = 1.7; 95% CI: 1.3-2.1), pancreatic cancer (SIR = 1.9; 95% CI: 1.2-2.9) and myeloid leukemia (SIR = 2.3; 95% CI: 0.9-4.7). We found no convincing association with neither breast nor colorectal cancer in women with BOTs. This is the first large nationwide study showing that women with specific types of BOTs have increased risks of several nonovarian cancers, likely due to some shared risk factors or genetic characteristics.

The relative and interactive impact of multiple risk factors in schizophrenia spectrum disorders: a combined register-based and clinical twin study

BACKGROUND

Research has yielded evidence for genetic and environmental factors influencing the risk of schizophrenia. Numerous environmental factors have been identified; however, the individual effects are small. The additive and interactive effects of multiple risk factors are not well elucidated. Twin pairs discordant for schizophrenia offer a unique opportunity to identify factors that differ between patients and unaffected co-twins, who are perfectly matched for age, sex and genetic background.

METHODS

Register data were combined with clinical data for 216 twins including monozygotic (MZ) and dizygotic (DZ) proband pairs (one or both twins having a schizophrenia spectrum diagnosis) and MZ/DZ healthy control (HC) pairs. Logistic regression models were applied to predict (1) illness vulnerability (being a proband v. HC pair) and (2) illness status (being the patient v. unaffected co-twin). Risk factors included: A polygenic risk score (PRS) for schizophrenia, birth complications, birth weight, Apgar scores, paternal age, maternal smoking, season of birth, parental socioeconomic status, urbanicity, childhood trauma, estimated premorbid intelligence and cannabis.

RESULTS

The PRS [odds ratio (OR) 1.6 (1.1-2.3)], childhood trauma [OR 4.5 (2.3-8.8)], and regular cannabis use [OR 8.3 (2.1-32.7)] independently predicted illness vulnerability as did an interaction between childhood trauma and cannabis use [OR 0.17 (0.03-0.9)]. Only regular cannabis use predicted having a schizophrenia spectrum diagnosis between patients and unaffected co-twins [OR 3.3 (1.1-10.4)].

CONCLUSION

The findings suggest that several risk factors contribute to increasing schizophrenia spectrum vulnerability. Moreover, cannabis, a potentially completely avoidable environmental risk factor, seems to play a substantial role in schizophrenia pathology.

Time trends in prevalence of p16 positivity and combined HPV/p16 positivity in a large cohort of Danish vulvar cancer patients

Vulvar cancer is rare, but causes substantial morbidity in affected patients. A subset of vulvar cancers is caused by high-risk human papillomavirus (hrHPV), which primarily exerts its oncogenic effect through upregulation of tumor suppressor protein p16. Tumors positive for both hrHPV and p16 (double positive) are assumed to be HPV-driven, but only few large studies have investigated the combined prevalence of hrHPV and p16 positivity in vulvar cancer over time. In this Danish cross-sectional study, we assessed the prevalence of p16 positivity and double positivity for hrHPV and p16 in a large sample of vulvar squamous cell carcinomas (VSCCs) diagnosed during 1990 to 2017. In a nationwide register, we identified VSCCs from 13 hospitals across Denmark, and collected archival tumor tissue for hrHPV testing with INNO-LiPA and immunohistochemical p16 staining. We calculated the prevalence of hrHPV, p16 positivity and double positivity according to time, age and histological subtype and evaluated time trends through estimated annual percentage changes. We included 1278 VSCCs. Overall, 35.0% (95% confidence interval [CI]: 32.4-37.6) were positive for p16 and 31.0% (95% CI: 28.4-33.5) were positive for both hrHPV and p16. The prevalence of p16 positivity and double positivity increased over time, both in women aged ≤59 and ≥60 years. The double positive prevalence was higher in nonkeratinizing (60.7%) and warty/basaloid VSCCs (67.5%) than in keratinizing (16.1%) and verrucous VSCCs (5.0%). These results indicate that approximately one-third of vulvar cancers were caused by hrHPV infection, supporting a substantial preventive potential of the HPV vaccine.

Changes in HPV prevalence in Danish women with vulvar cancer during 28 years - A nationwide study of >1300 cancer cases

OBJECTIVE

A substantial proportion of vulvar cancers are caused by high-risk human papillomavirus (hrHPV), but hrHPV prevalence in vulvar cancer has mainly been investigated in smaller studies which did not evaluate time trends. Our aim was to assess hrHPV prevalence in >1300 Danish vulvar cancers diagnosed during 1990-2017, including changes in hrHPV prevalence over time.

METHODS

In a nationwide pathology register, we identified women diagnosed with vulvar cancer at thirteen hospitals from all Danish regions. Archival tumor tissue was collected from local repositories and, upon pathology review, sent to a central laboratory for HPV testing using INNO-LiPA. We calculated hrHPV prevalence according to time, age and histology, and evaluated the overall and age-specific estimated annual percentage change (EAPC).

RESULTS

We included 1308 vulvar cancer cases, with a median age of 72 years at diagnosis. The overall hrHPV prevalence was 52.0% (95% CI: 49.3-54.7). HPV types 16/18 were found in 39.6% of cases, whereas nine-valent HPV (9vHPV) vaccine types 16, 18, 31, 33, 45, 52, and 58 were found in 50.8%. The hrHPV prevalence showed an increasing trend over time, with an EAPC of 0.35% (95% CI: 0.00-0.71). The hrHPV prevalence was higher in younger women throughout the study period, and increasing trends over time were seen in both older (age ≥ 60) and younger (age < 60) women. The hrHPV prevalence was higher in non-keratinizing (71.0%) and warty/basaloid (78.0%) carcinomas than in keratinizing (39.4%) and verrucous (36.4%) carcinomas.

CONCLUSIONS

Our results indicate that the 9vHPV vaccine could potentially prevent a substantial proportion of vulvar cancers in Denmark.

Long-term survival of non-localized epithelial ovarian cancer among women using menopausal hormone therapy prior to diagnosis - the Extreme study

Prediagnostic use of menopausal hormone therapy (MHT) has been suggested to be associated with improved survival of epithelial ovarian cancer (EOC). We investigated the potential long‐term survival benefit of prediagnostic MHT use in women ≥50 years with nonlocalized EOC using the Extreme study including all women in Denmark registered with nonlocalized EOC during 2000 to 2014 (N = 3776). We obtained individual‐level information on prediagnostic use of systemic estrogen therapy (ET) and estrogen plus progestin therapy (EPT) from the National Prescription Registry and estimated absolute and relative 5‐ and 10‐year survival probabilities with 95% confidence intervals (CIs) using pseudo‐values, taking into account histology, comorbidity, income and residual disease. Among women not having used prediagnostic MHT, 5‐ and 10‐year absolute survival probabilities were 19% and 11%, respectively. Compared to MHT nonusers, prediagnostic systemic ET use for 3 to 4 years and ≥ 5 years was associated with 1.43 (95% CI: 1.01‐2.02) and 1.22 (95% CI: 0.96‐1.55) times higher 5‐year survival probabilities, respectively. Ten‐year survival probabilities were also increased but not statistically significantly. Among prediagnostic EPT users, increased 5‐year (1.14, 95% CI: 0.85‐1.53) and 10‐year (1.38, 95% CI: 0.91‐2.08) survival probabilities were observed after use for 3 to 4 years compared to MHT nonuse, whereas EPT use for ≥5 years was not associated with long‐term survival of nonlocalized EOC. Our findings may suggest a better long‐term survival of nonlocalized EOC in women having used long‐term prediagnostic ET. However, the statistical precision of our results did not allow firm conclusions and more studies are needed.

Trends in survival of epithelial ovarian/tubal cancer by histology and socioeconomic status in Denmark 1996-2017

OBJECTIVES

To examine time trends in ovarian/tubal cancer relative survival, excess mortality, and all-cause mortality for different histological types and levels of socioeconomic position.

METHODS

Women with ovarian/tubal cancer diagnosed 1996-2017 were identified in the Danish Cancer Registry (n = 11,755). Age-standardized 5-year relative survival over time was estimated by histology, socioeconomic status, and stage. Furthermore, 5-year excess mortality rate ratios (EMRR) according to calendar time for all categories of histology and socioeconomic status were calculated using a Poisson regression model. Finally, all-cause mortality by histology and socioeconomic status was estimated in multivariate Cox proportional hazards regression models.

RESULTS

Statistically significant improvements in 5-year relative survival occurred for all histological types over time except mucinous tumors (5-year EMRR, localized: 0.92 (95% CI: 0.71-1.16); advanced: 0.96 (95% CI: 0.85-1.08). Increase in relative survival over time and corresponding decrease in excess mortality was observed for all categories of socioeconomic status except for women with localized disease in the lowest income group (5-year EMRR = 0.91 (95% CI:0.76-1.10)). The impact of histology and socioeconomic status on all-cause mortality depended on time since diagnosis. Among the socioeconomic factors, especially low educational level and living alone were associated with increased all-cause mortality, particularly in the first year after diagnosis.

CONCLUSIONS

Ovarian/tubal cancer survival generally increased over time across histological types and socioeconomic factors. However, the lack of improvement for mucinous tumors needs further research. Additionally, the results for women with low income and education shows that continued focus on social equality in survival is necessary.

Real-World Effectiveness of Human Papillomavirus Vaccination Against Cervical Cancer

BACKGROUND

The primary goal of human papillomavirus (HPV) vaccination is to reduce morbidity and mortality from HPV-associated disease, especially cervical cancer. We determined the real-world effectiveness of HPV vaccination against cervical cancer.

METHODS

The study included women aged 17-30 years living in Denmark October 2006-December 2019. From nationwide registries, information on HPV vaccination and cervical cancer diagnoses were retrieved. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for cervical cancer according to vaccination status were estimated using Poisson regression with HPV vaccination treated as a time-varying variable and stratified by age at vaccination. We adjusted for attained age, education, and ethnicity. To address the effect of prevalent disease, different buffer periods were used, with 1-year buffer period as primary analysis.

RESULTS

The cohort comprised 867 689 women. At baseline, 36.3% were vaccinated at age 16 years and younger, and during follow-up, 19.3% and 2.3% were vaccinated at ages 17-19 years and 20-30 years, respectively. For women vaccinated at ages 16 years and younger or 17-19 years, the IRRs of cervical cancer were 0.14 (95% CI = 0.04 to 0.53) and 0.32 (95% CI = 0.08 to 1.28), respectively, compared with unvaccinated women. In women aged 20-30 years at vaccination, the incidence rate was higher than among unvaccinated women (IRR = 1.19, 95% CI = 0.80 to 1.79) but slightly decreased with increasing buffer period (IRR = 0.85, 95% CI = 0.55 to 1.32, with 4-year buffer period).

CONCLUSION

HPV vaccine effectiveness against cervical cancer at the population level is high among girls vaccinated younger than age 20 years. The lack of immediate effect in women vaccinated at age 20-30 years points to the importance of early age at vaccination.

Prediction of drop-out and functional impairment in recent-onset schizophrenia spectrum disorders

Persistent negative symptoms are associated with worse outcome in both first-episode and chronic subjects with schizophrenia. The identification of these symptoms in recent-onset subjects is still controversial as retrospective data are often unavailable. The prospective assessment of persistence of negative symptoms might represent a valid alternative but the length of the persistence is still to be established. The present study investigated the prevalence of negative symptoms of moderate severity, unconfounded by depression and extrapyramidal symptoms at baseline in a large cohort of patients in the early stage of a schizophrenia-spectrum disorder, recruited to the OPTiMiSE trial. Persistent unconfounded negative symptoms were assessed at 4, 10 and 22 weeks of treatment. Symptomatic remission, attrition rate and psychosocial functioning was evaluated in subjects with short-term (4 weeks) persistent negative symptoms (PNS) and in those with negative symptoms that did not persist at follow-up and/or were confounded at baseline (N-PNS). Negative symptoms of moderate severity were observed in 59% of subjects at baseline and were associated to worse global functioning. PNS were observed in 7.9% of the cohort, unconfounded at both baseline and end of 4-week treatment. PNS subjects showed lower remission and higher attrition rates at the end of all treatment phases. Fifty-six percent of subjects completing phase 3 (clozapine treatment) had PNS, and 60% of them were non-remitters at the end of this phase. The presence of short-term PNS during the first phases of psychosis was associated with poor clinical outcome and resistance to antipsychotic treatment, including clozapine.

Prognostic impact of socioeconomic status on long-term survival of non-localized epithelial ovarian cancer ꟷ The Extreme study

OBJECTIVE

To examine the influence of socioeconomic status (SES) on long-term survival of non-localized ovarian cancer.

METHODS

All women in Denmark with a first diagnosis of non-localized epithelial ovarian cancer 1982-2007 were identified in the Cancer Registry and/or the Pathology Registry and followed up until December 2017. The survival probability was estimated after respectively 5 and 10 years, using so-called pseudo observations, and analyzed according to education, income, and marital status defined from nationwide registries.

RESULTS

The study cohort included 6486 women, and the estimated 5- and 10-year survival probabilities were 21.4% and 12.7%, respectively. Compared to women with short education, the 5-year survival probability was 7% higher for women with medium (relative survival probability = 1.07, 95% CI: 0.97, 1.19) and long education (relative survival probability = 1.07, 95% CI: 0.93, 1.24). Compared with married women, the 5-year survival probability for divorced women/widower was slightly lower (0.85, 95% CI: 0.69, 1.04) and for unmarried women slightly higher (1.08, 95% CI: 0.94, 1.23). Finally, the probability of being alive 5 years after diagnosis was 1.09 times higher (95% CI: 0.95, 1.24) for medium-income women and 1.23 times higher (95% CI: 1.08, 1.41) for high-income women compared with low-income women. Similar patterns were observed for 10-year survival.

CONCLUSIONS

Non-localized ovarian cancer patients have a poor prognosis. Our data suggest that among Danish women with advanced ovarian cancer, higher personal income is associated with slightly higher probability of long-term survival, whereas education and marital status did not affect the probability of long-term survival.

Real-World Effectiveness of Human Papillomavirus Vaccination Against Vulvovaginal High-Grade Precancerous Lesions and Cancers

BACKGROUND

Vaccination against human papillomavirus (HPV) has proven to be effective against severe cervical lesions and genital warts, whereas no previous study has provided real-world data on the HPV vaccine effectiveness against high-grade vulvovaginal lesions.

METHODS

A cohort of all women age 17-26 years living in Denmark during 2006-2019 was followed in nationwide registers for individual-level information about HPV vaccination and first diagnoses of vulvar and vaginal high-grade squamous intraepithelial lesions (HSIL+) or worse. The cumulative incidence of vulvar and vaginal HSIL+, respectively, was estimated with the Aalen-Johansen estimator, and Cox proportional hazards regression was used to estimate hazard ratios (HRs) for vulvar and vaginal lesions separately, comparing women vaccinated at age 16 years or younger and at age 17-26 years with unvaccinated women.

RESULTS

The cohort consisted of 514 537 women, of which 50.6% were vaccinated at baseline (<16 years), 31.8% were vaccinated during follow-up (17-26 years), and 17.6% remained unvaccinated. The cumulative incidence was less than 0.6‰ for vulvar HSIL+ and less than 0.2‰ for vaginal HSIL+. Adjusted analyses showed reduced HRs for both vulvar (HR = 0.22, 95% confidence interval = 0.13 to 0.38) and vaginal HSIL+ (HR = 0.16, 95% confidence interval = 0.04 to 0.55) for women vaccinated at age 16 years or younger compared with unvaccinated women. For women vaccinated at 17-26 years of age, the reductions in HRs were smaller for vaginal HSIL+ and close to 0 for vulvar HSIL+.

CONCLUSIONS

HPV vaccination before 17 years of age reduces the risk of vulvar and vaginal HSIL+ based on real-world data.

Borderline ovarian tumors in Denmark 1997-2018: Time trends in incidence by histology, age and educational level

INTRODUCTION

After some decades with an increasing incidence of borderline ovarian tumors, more recent studies have observed that the incidence rate seems to be leveling off or declining. In this study, we describe the incidence of borderline ovarian tumors in Denmark 1997-2018 by histology, age at diagnosis and educational level.

MATERIAL AND METHODS

All borderline ovarian tumors registered in the Danish Pathology Registry during 1997-2018 were identified and individual-level educational information was retrieved from nationwide registers. Age-standardized incidence rates were estimated according to histology, age at diagnosis and educational level. To investigate incidence trends over time, the average annual percentage change and corresponding 95% confidence intervals (CIs) were estimated using Poisson regression.

RESULTS

We identified 3927 women with borderline ovarian tumors during the study period, of which 1997 (50.9%) were serous and 1743 (44.4%) were mucinous. The age-standardized incidence rate of serous borderline ovarian tumors did not change significantly over calendar time (average annual percentage change = -0.13, 95% confidence interval [CI] -1.13 to 0.88). For mucinous tumors, the age-standardized incidence rate was also relatively stable during the first half of the study period, followed by a decrease from 2.56 to 1.25 per 100 000 person-years between 2007-2011 and 2017-2018. Over the entire study period, the incidence rate of mucinous borderline tumors declined on average by 2.91% (95% CI -4.24 to -1.51) per year. The incidence of both types of borderline ovarian tumors seemed to be highest among women with a low educational level. Over calendar time, the incidence of mucinous tumors decreased in all educational groups, whereas the incidence of serous tumors decreased exclusively in women with a high educational level. Time trends did not differ markedly by age at diagnosis.

CONCLUSIONS

In Denmark, the incidence of serous borderline ovarian tumors was stable during 1997-2018, whereas the incidence of mucinous borderline ovarian tumors decreased. The incidence rates of both types of borderline ovarian tumors tended to be highest among women with a low educational level throughout the study period.

One-Dose Human Papillomavirus Vaccination and the Risk of Genital Warts: A Danish Nationwide Population-based Study

BACKGROUND

Increasing evidence suggests that 1-dose human papillomavirus (HPV) vaccination may protect significantly against HPV-related disease. We provide nationwide, real-world data on the risk of genital warts (GWs) after <3 vaccine doses.

METHODS

All Danish women born in 1985-2003 were identified, and individual-level vaccination data were retrieved. The cohort was followed up for first occurrence of GWs until 31 December 2016. Using Poisson regression, we calculated incidence rates (IRs) of GWs per 100 000 person-years and IR ratios (IRRs) with corresponding 95% confidence intervals (CIs) for GWs, according to vaccination status, age at first dose, and calendar time.

RESULTS

The cohort comprised 1 076 945 girls and women, of whom 485 408 were vaccinated. For girls initiating vaccination at age 12-14 years and 15-16 years, 1-dose vaccine effectiveness (VE) was 71% (IRR = 0.29; 95% CI, .22-.38) and 62% (0.38; .29-.49), respectively, compared with unvaccinated girls. In the same age groups, 2-dose VE was 78% (IRR, 0.22; 95% CI, .18-.26) and 68% (0.32; .26-.38), respectively. After 2009, the IRRs for 3 versus 1 dose and 2 versus 1 dose increased towards unity over calendar time, being 0.69 (95% CI, .57-.84) and 0.86 (.68-1.08) in 2016, respectively.

CONCLUSIONS

In this study, 1 or 2 doses of quadrivalent HPV vaccine was associated with substantial protection against GWs in girls vaccinated at age ≤16 years. The 1-dose VE approached that of 3 or 2 doses over calendar time, probably reflecting the impact of herd protection.

The current epidemic of HPV-associated oropharyngeal cancer: An 18-year Danish population-based study with 2,169 patients

BACKGROUND

The objectives of this study were to investigate the incidence of high-risk genotypes of human papillomavirus (HPV) in tumours of patients with oropharyngeal squamous cell carcinoma (OPSCC) during an 18-year period in Eastern Denmark.

METHODS

In this population-based, consecutive, semi-national registry study, all patients diagnosed with OPSCC from 2000 to 2017 in Eastern Denmark were evaluated at head and neck oncological departments at public university hospitals. Analyses included tumour characteristics (HPV-positive [HPV+] versus HPV-negative [HPV-]), age-adjusted incidence rates (AAIRs), average annual percentage change (AAPC) of OPSCC, and patient demographics. All HPV+ cases from 2011 to 2017 were genotyped.

RESULTS

In total, 55% of 2169 OPSCC cases were HPV+. HPV16, HPV33, HPV35 or other types were found in 86%, 7.4%, 3.4% and 3.2% of cases, respectively. The AAIR per 100,000 of all OPSCCs was 1.8 in 2000, which increased to 5.1 in 2017 (HPV+: threefold increase, HPV-: twofold increase). The AAPC from 2000 to 2017 increased by 7% (HPV+ increased by 10% and HPV- by 4%). The median age at diagnosis for all OPSCC cases increased during the 18-year study period (HPV+: 58-61 years, p < 0.001; HPV-: 60-65 years, p < 0.001).

CONCLUSION

We report a threefold increase in OPSCC incidence during the 18-year observation period and a significant increase in median age at diagnosis. Over 93% of HPV genotypes in HPV+ OPSCC are included in current HPV vaccines except for HPV35 (4%). HPV vaccination of both sexes is advised to halt this emerging cancer epidemic.

Non-epithelial ovarian cancer in Denmark - Incidence and survival over nearly 40 years

OBJECTIVE

To examine trends in incidence and survival of non-epithelial ovarian cancer in Denmark over nearly 40 years, using nationwide, population-based cancer registry data.

METHODS

From 1978 to 2016, we identified the non-epithelial ovarian cancer cases among all ovarian malignancies in the Danish Cancer Registry. Age-specific incidence rates, age-standardized incidence rates, and average annual percentage change (AAPC) were estimated with 95% confidence intervals (CIs). Overall and 5-year relative survival analyses were conducted and supplemented with Cox regression to explore the effect of different characteristics on overall mortality.

RESULTS

A total of 720 non-epithelial ovarian cancers were identified, corresponding to 3.4% of all ovarian malignancies. The majority of non-epithelial ovarian cancers were germ cell tumors (49.9%) and sex cord-stromal tumors (38.6%). The age-standardized incidence rate of germ cell tumors was stable over the study period, ranging between 0.33 and 0.39 per 100,000 woman-years. In contrast, the age-standardized incidence rate of sex cord-stromal tumors declined from 0.30 (1978-1987) to 0.09 (2008-2016) per 100,000 woman-years (AAPC = -5.15%; 95% CI: -7.29, -2.96). The 5-year relative survival of germ cell tumors and sex cord-stromal tumors was 94% and 79%, respectively, in the most recent period (2008-2011). Cox regression showed that overall mortality was associated with calendar year, age, and stage.

CONCLUSIONS

The incidence of germ cell tumors was stable over calendar time, whereas the incidence of sex cord-stromal tumors decreased significantly. Non-epithelial ovarian cancer overall mortality has decreased during the study period and this could not be explained by taking stage and age at diagnosis into account.

[Perspectives on recurrent respiratory papillomatosis and human papillomavirus]

Recurrent respiratory papillomatosis (RRP) is a condition with benign tumours in the respiratory tract. RRP ensues in both children and adults. The disease is induced by low-risk human papillomavirus (HPV) types HPV-6 and HPV-11. RRP have a recurrent nature with symptoms ranging from hoarseness, dyspnoea, and dysphagia to life-threatening airway obstructions. Currently, no medical curative treatment of RRP is available, however, the literature indicates, that the HPV-vaccines could protect against RRP by preventing genital warts.

Conceptualizing patient-reported outcome measures for use within two Danish psychiatric clinical registries: description of an iterative co-creation process between patients and healthcare professionals

BACKGROUND

Denmark has national clinical indicator programs for adult patients diagnosed with depression and schizophrenia, respectively. Within each program, the responsible steering group (SG) decided to add some indicators based upon patient-reported outcome measures (PROMs).

AIMS

The primary aim was to describe the process of selecting PROMs and defining a national measurement concept for use in clinical practice and for indicator monitoring and the secondary aim s to collect patient recommendations for implementation.

METHODS

An interdisciplinary SG of healthcare professionals and a Patient Peer Board (PPB) representing both patient groups co-created the output in an iterative process. The work included literature search, PPB workshops, SG meetings, ratings of PROM topics and items, and a pilot. The PPB discussed the following: item relevance, mode of data collection, graphical format of the online PROMs, and display of results. Finally, requirements for PROM patient information were identified. Based upon input from the PPB, the SG selected the items and specified the measurement concept.

RESULTS

The PPB prioritized 20 of 53 suitable items and suggested alternative wording and answer categories. A pilot was performed and 19 items covering well-being, lack of well-being, impairment of functioning, and overall health were selected for clinical testing. The patients recommended concrete, unambiguous, easily understandable information and procedures for data collection and display of results.

CONCLUSIONS

The iterative co-creation process based upon a high degree of patient involvement resulted in a set of PROMs, a national measurement concept, and patient recommendations for implementation. The cooperation between patients and professionals was successful.

Use of antidepressants and risk of epithelial ovarian cancer

Antidepressants are widely prescribed among women to treat depression and anxiety disorders, but studies of their effects on gynecological cancer risk are sparse. We assessed associations between various antidepressants and risk of epithelial ovarian cancer. By using Danish nationwide registers, we identified all women (cases) aged 30-84 years with incident epithelial (serous, endometrioid, clear cell or mucinous) ovarian cancer during 2000-2011 (n = 4,103) and matched each case to 20 population controls (n = 58,706) by risk-set matching. Data on drug use (including tricyclic and related antidepressants, selective serotonin reuptake inhibitors, other antidepressants, and potential confounder drugs), medical and reproductive history and socioeconomic parameters, were obtained from nationwide registries. We used conditional logistic regression models to estimate adjusted odds ratios (ORs) and two-sided 95% confidence intervals (CIs) for epithelial ovarian cancer associated with antidepressive drug use. Compared with non-use, use of selective serotonin reuptake inhibitors was associated with a decreased risk of ovarian cancer (OR, 0.85; 95% CI, 0.74-0.96), whereas the associations for other antidepressants were close to unity [tricyclic and related antidepressants: OR, 0.99 (95% CI, 0.78-1.26); other antidepressants: OR, 1.05 (95% CI, 0.76-1.46)]. For individual types of SSRI, reduced ORs were observed for citalopram OR, 0.78 (95% CI, 0.66-0.93), paroxetine 0.79 (95% CI, 0.56-1.12) and sertraline 0.80 (95% CI, 0.60-1.08). Among postmenopausal women, the inverse association was restricted to users of menopausal hormone therapy. In conclusion, use of selective serotonin reuptake inhibitors was associated with a decreased risk of epithelial ovarian cancer; thereby implying potential chemopreventive properties of these drugs.

Parity, infertility, oral contraceptives, and hormone replacement therapy and the risk of ovarian serous borderline tumors: A nationwide case-control study

OBJECTIVE

Few studies have examined the risk of an ovarian serous borderline tumor (SBT) associated with parity, infertility, oral contraceptives (OCs), or hormone replacement therapy (HRT), which was the study aim.

METHODS

This nationwide case-control study included all women with an SBT diagnosis in Denmark, 1978-2002. SBTs were confirmed by centralized expert pathology review. For each case, 15 age-matched female controls were randomly selected using risk-set sampling. Cases and controls with previous cancer (except for non-melanoma skin cancer) and controls with bilateral oophorectomy or salpingo-oophorectomy were excluded. Conditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We found a strongly decreased risk of SBTs among parous women which decreased with increasing number of children (p<0.01). Older age at first birth also decreased the SBT risk (p=0.03). An increased SBT risk was associated with infertility (OR=3.31; 95% CI: 2.44-4.49), which was present both among parous and nulliparous women. HRT use increased the SBT risk (OR=1.32; 95% CI: 1.02-1.72), whereas OC use decreased the risk (OR=0.40; 95% CI: 0.26-0.62).

CONCLUSIONS

Our nationwide study with expert histopathologic review of all SBTs showed that parity, infertility, use of HRT, and use of OCs, respectively, were strongly associated with the risk of SBTs. This is the first study to report a strong and significantly decreased SBT risk associated with OC use and a significantly increased risk with infertility, and HRT use. This supports that SBTs and serous ovarian cancer share similar risk factors.

New users of antipsychotic medication: A population-based cohort study of occupational outcome measures in relation to antipsychotic on-label and off-label prescribing practices

BACKGROUND

Treatment with antipsychotic medication is thoroughly investigated in schizophrenia and bipolar disorder but is also widely applied for a diversity of off-label conditions, despite an uncertain risk-benefit ratio. This study examined the relationship between antipsychotic prescribing patterns and labor market affiliation, considering both authority approved and off-label prescriptions and the relation to polypharmacy.

METHODS

Register-based cohort study using a dataset of 71,254 new antipsychotic users with a psychiatric diagnosis. Labor market affiliation and duration of welfare payments were analyzed using linear regression models and duration analysis. The analyses were adjusted for the following confounding variables: age, gender, diagnosis, marital status, length of education, and utilization of mental health care services.

RESULTS

The majority of new antipsychotic users received welfare payments for prolonged periods of time during the observation period, even more so for individuals treated with antipsychotic polypharmacy or other antipsychotic combination regimens. The risk of permanently leaving the labor market was also associated with antipsychotic combination regimen.

CONCLUSIONS

Antipsychotic treatment, especially in combination with other antipsychotics or other psychotropic drugs, could serve as a marker of subjects with increased need for support to maintain the labor market affiliation. However, causality cannot be inferred from an observational study because of residual confounding that could not be adjusted for in this study.

Drugs with potential chemopreventive properties in relation to epithelial ovarian cancer--a nationwide case-control study

Ovarian cancer has a poor prognosis because the disease in the majority of patients is diagnosed at an advanced stage as a result of nonspecific symptoms and lack of efficient screening methods. Because of the poor prognosis of ovarian cancer and the challenge of early detection of the disease, identification of protective factors is important. It has been suggested that some commonly used drugs may have a protective effect against cancer, including ovarian cancer; however, the literature on chemopreventive measures for ovarian cancer is sparse and the results are inconclusive. Most previous studies have substantial methodological constraints, including limited study size and self-reporting of drug use, which introduces potential recall bias and misclassification. This PhD thesis includes a nationwide case-control study to evaluate associations between use of drugs with potential chemopreventive properties and risk of epithelial ovarian cancer. The study is nested in the entire Danish female population using data from the following nationwide registries: the Danish Cancer Registry, the Danish Civil Registration System, the Danish Prescription Registry, the Danish National Patient Register, and registries in Statistics Denmark on fertility, education, and income. Information from the included registries is linked by use of the unique personal identification number assigned to all Danish citizens. The cases were all women in Denmark with epithelial ovarian cancer diagnosed during 2000-2009 (Paper 1) and 2000-2011 (Papers 2 and 3), identified in the Cancer Registry. Age-matched female population controls were randomly selected from the Civil Registration System by risk-set sampling. We required that cases and controls have no history of cancer (except non-melanoma skin cancer) and that controls not previously have undergone bilateral oophorectomy or salpingo-oophorectomy. The total study population comprised 3741 epithelial ovarian cancer cases and 50,576 controls in Paper 1, and 4103 epithelial ovarian cancer cases and 58,706 controls in Papers 2 and 3. We used the Danish Prescription Registry to assess use (≥2 prescriptions on separate dates) of paracetamol, non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs), low-dose aspirin, and statins. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for epithelial ovarian cancer associated with use of the study drugs, with adjustment for potential confounding factors selected a priori. We performed detailed analyses according to duration, intensity, and continuity of study drug use, and the analyses were stratified according to specific histologic types of epithelial ovarian cancer. In all studies, non-use (< 2 prescriptions) of the individual study drugs was defined as the reference group. A striking result of the PhD thesis was a strong inverse association between prescription use of paracetamol and risk of epithelial ovarian cancer. The risk estimates decreased with increasing duration and intensity of paracetamol use, reaching a more than 50% reduction for the longest duration (>10 years) and the highest doses (OR: 0.45; 95% CI: 0.24-0.86). In contrast, we did not observe an inverse association between use of non-aspirin NSAIDs and risk of epithelial ovarian cancer. Moreover, this thesis provides further evidence that use of low-dose aspirin is associated with a reduced risk of epithelial ovarian cancer. In particular, long-term (≥5 years) continuous use of low-dose aspirin, defined as overlapping prescription coverage periods, was associated with a large reduction in risk (OR: 0.56; 95% CI: 0.32-0.97). Finally, we found no apparent association between statin use and epithelial ovarian cancer risk, although the analysis by histologic type suggested an inverse association with the risk of mucinous tumors. The results of this PhD thesis add important knowledge to the area of chemoprevention in relation to epithelial ovarian cancer. As for any observational study, we cannot exclude potential con-founding and exposure misclassification; however, methodological limitations appear unlikely to fully explain the observed reductions in epithelial ovarian cancer risk associated with paracetamol and low-dose aspirin use. Additional research, ideally from clinical trials, is needed before our observations may lead to recommendations for chemopreventive measures against ovarian cancer. In case consensus points to a true protective effect of paracetamol or low-dose aspirin, comprehensive risk-benefit evaluations will also have to be performed. We hope that our results will encourage researchers to look more deeply into the potential chemo-preventive effects of the study drugs against epithelial ovarian cancer risk.

Use of nonsteroidal anti-inflammatory drugs and risk of endometrial cancer: a nationwide case-control study

PURPOSE

We examined the association between use of low-dose aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) and endometrial cancer risk in a nationwide case-control study.

METHODS

Cases were all women in Denmark diagnosed with endometrial cancer during 2000-2009. Age-matched female controls were randomly selected by risk-set sampling. Information on NSAID use was collected from the Prescription Registry and classified according to duration and intensity. Conditional logistic regression was used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs), adjusting for potential confounders. Analyses were stratified by endometrial cancer type, and potential effect modification by parity, obesity, and hormone replacement therapy (HRT) use was investigated.

RESULTS

We identified 5,382 endometrial cancer cases and 72,127 controls. Endometrial cancer was not associated with use of low-dose aspirin (OR 0.97, 95 % CI 0.89-1.05) or non-aspirin NSAIDs (OR 0.96, 95 % CI 0.91-1.02) compared with nonuse. The ORs did not vary with increasing duration or intensity of NSAID use or with type of endometrial cancer. Interaction analyses showed reduced endometrial cancer risk associated with low-dose aspirin use among nulliparous women (OR 0.82, 95 % CI 0.70-0.95) and with non-aspirin NSAID use among women having used HRT (OR 0.90, 95 % CI 0.82-0.99).

CONCLUSIONS

We found no association between use of NSAIDs and endometrial cancer risk overall, although there were some indications of risk reductions associated with low-dose aspirin use among nulliparous women and with non-aspirin NSAID use among women having used HRT.

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis

BACKGROUND

Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations.

METHODS

We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure.

FINDINGS

We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects.

INTERPRETATION

Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement.

FUNDING

The Canadian Institutes of Health Research.

Tubal ligation and salpingectomy and the risk of epithelial ovarian cancer and borderline ovarian tumors: a nationwide case-control study

OBJECTIVE

According to the recent theories on the ovarian cancer origin, any protective effect of tubal ligation may vary with histologic subtype of ovarian cancer. Furthermore, bilateral salpingectomy may represent an opportunity for surgical prevention of serous ovarian cancer.

DESIGN

Nationwide register-based case-control study.

SETTING

Denmark during 1982-2011.

POPULATION

Cases were all Danish women diagnosed with epithelial ovarian cancer (n = 13 241) or borderline ovarian tumor (n = 3605) in the study period. Age-matched female population controls were randomly selected by risk set sampling. We required that cases and controls have no previous cancer and that controls have no previous bilateral oophorectomy.

METHODS

Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusting for potential confounders.

MAIN OUTCOME MEASURES

Epithelial ovarian cancer and borderline ovarian tumors stratified according to histology.

RESULTS

Tubal ligation reduced overall epithelial ovarian cancer risk (odds ratios 0.87; 95% confidence interval 0.78-0.98). We observed significant risk variation according to histology (p = 0.003) with the strongest risk reductions associated with endometrioid cancer (odds ratios 0.66; 95% confidence interval 0.47-0.93) and epithelial ovarian cancer of "other" histology (odds ratios 0.60; 95% confidence interval 0.43-0.83). Tubal ligation was not associated with risk of borderline ovarian tumors. Finally, bilateral salpingectomy reduced epithelial ovarian cancer risk by 42% (odds ratios 0.58; 95% confidence interval 0.36-0.95).

CONCLUSIONS

We confirmed that tubal ligation reduces the risk of epithelial ovarian cancer and particularly endometrioid cancer. To our knowledge, this is the first observational publication to report on salpingectomy and ovarian cancer risk and our promising findings warrant further investigation.

The prevalence of human papillomavirus in colorectal adenomas and adenocarcinomas: a systematic review and meta-analysis

BACKGROUND

The role of human papillomavirus (HPV) in colorectal cancer has been widely studied with conflicting results. We performed a systematic review and a meta-analysis to estimate the prevalence of HPV in colorectal adenocarcinomas and adenomas, and test the potential association.

METHODS

The pooled HPV prevalence was estimated using a random effects model and the I(2) statistic was used to describe the amount of heterogeneity. Potential sources of heterogeneity were evaluated by meta-regression and stratified analyses. For the studies on adenocarcinomas including control tissue, random effects estimates of odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

Thirty-seven studies were included. Among the 2630 adenocarcinomas, the pooled HPV prevalence was 11.2% (95% CI, 4.9-19.6%) with substantial between-study heterogeneity (I(2)=97.2%). The HPV prevalence varied by geographical region with highest prevalence in South America (45.1%, 95% CI, 21.9-69.4%), Asia (39.2%, 95% CI, 20.3-60.0%) and the Middle East (32.2%, 95% CI, 1.1-79.3%), and by detection method with the highest HPV prevalence in PCR-based studies. In the eight case-control studies, the pooled HPV prevalence was 36.8% (95% CI, 21.3-53.8%) in adenocarcinomas and 1.6% (95% CI, 0.0-9.6%) in controls giving an OR of 6.0 (95% CI, 2.0-17.9%) for the association between HPV and colorectal cancer. Among the 415 adenomas, the pooled HPV prevalence was 5.1% (95% CI, 0.0-17.8%; I(2)=93.7%).

CONCLUSIONS

HPV may be associated with a subset of colorectal cancers. Future large-scale multicenter case-control studies with data on risk factors such as lifestyle and sexual behaviour are needed.

Nonsteroidal anti-inflammatory drugs and risk of ovarian cancer: systematic review and meta-analysis of observational studies

OBJECTIVE

Several observational studies have investigated the association between nonsteroidal anti-inflammatory drug (NSAID) use and ovarian cancer risk, but with conflicting results. We performed a systematic review and meta-analysis of the association between NSAID use and ovarian cancer risk.

DESIGN

Systematic review and meta-analysis of observational studies published until September 2012.

SETTING

Studies were identified from the PubMed database.

POPULATION

Fourteen case-control and seven cohort studies were included.

METHODS

Pooled relative risks (RRs) with corresponding 95% confidence intervals (CI) for aspirin and non-aspirin NSAIDs, separately, were calculated. Both fixed and random effect models were applied, but only random effect pooled RRs are presented. Risk estimates for invasive and borderline ovarian tumors combined and for invasive ovarian tumors only were calculated. Furthermore, heterogeneity and publication bias were evaluated.

MAIN OUTCOME MEASURES

Ovarian cancer.

RESULTS

In the combined analysis, a slight inverse association between use of aspirin (RR 0.93; 95% CI 0.84-1.02) and non-aspirin NSAIDs (RR 0.94; 95% CI 0.84-1.06) and ovarian cancer risk was found, although it was not statistically significant. However, the risk of invasive ovarian cancer was significantly reduced with use of aspirin (RR 0.88; 95% CI 0.79-0.98). A similar tendency was observed for non-aspirin NSAIDs, but the results were not significant.

CONCLUSIONS

This meta-analysis showed a slight inverse association between NSAIDs and risk of ovarian cancer. However, data suggest that a chemopreventive effect of NSAIDs may be restricted to invasive ovarian tumors. Further research on NSAIDs and ovarian cancer is needed before definite conclusions can be drawn.

HPV16 is associated with younger age in women with cervical intraepithelial neoplasia grade 2 and 3

OBJECTIVE

To evaluate if women with HPV16 positive CIN2 and CIN3 are diagnosed at a younger age.

METHODS

We conducted a population-based cohort study including more than 40,000 women having a liquid based cervical cytology sample taken as part of routine screening. HPV analysis was performed using Hybrid Capture 2 and LiPAv2. The study population was linked to the Danish Pathology Data Bank to retrieve information on subsequent cervical histology. We included HR HPV positive CIN2/3 samples, comprising 173 CIN2 and 467 CIN3 lesions. Due to a high number of multiple concurrent HPV infections, the causative HPV type was assigned to a hierarchically group.

RESULTS

In CIN3, the estimated proportion of lesions positive for HPV16 was 68.1% among women aged 20 years and decreased to 38.9% among women aged 50 years. A decrease in HPV16 positivity with increasing age was also observed in CIN2. In a multinomial logistic regression analysis, young age was strongly associated with HPV16 positivity in CIN3 lesions (OR=0.46 per 10 year increase in age, 95% CI: 0.32-0.65). The proportion of HPV16 and/or 18 positive lesions among women diagnosed with CIN2 and CIN3 below 30 years of age was 44% and 75%, respectively.

CONCLUSIONS

HPV16 positivity was significantly associated with younger age at diagnosis of CIN3. In a population vaccinated against HPV16 and 18, we will experience a shift to older ages in cervical precancerous lesions. These findings may imply that cervical cancer screening programs could start at an older age in HPV vaccinated populations.

Chronic post-traumatic headache--a clinical analysis in relation to the International Headache Classification 2nd Edition

The clinical presentation of chronic post-traumatic headache in 53 patients from a highly specialized headache clinic was analysed and classified according to the diagnostic criteria of the primary headaches in The International Headache Classification 2nd Edition, and compared with the 1st Edition. All patients fulfilled the criteria for both editions indicating that the restrictions in the 2nd Edition have no major influence on the prevalence in specialized clinics. We found the phenomenology to be very heterogeneous, but the vast majority (77%) of patients presented with headache resembling chronic tension-type headache, either as the only manifestation or in combination with migraine symptoms. For the first time episodic tension-type headache is described as occurring after head trauma. The prevalence of coexisting analgesic overuse was 42% and the treatment outcome for these patients was just as favourable as in primary headaches, whereas the time-consuming multidisciplinary treatment demonstrated only very modest results.