Ovarian cancer risk factors in relation to family history.

BACKGROUND: Women with a family history of breast and/or ovarian cancer have an increased ovarian cancer risk. Yet it remains uncertain if common ovarian cancer risk factors-especially those which are modifiable-affect this high-risk population similarly to the general population. METHODS: Using the Danish and Swedish nationwide registers, we established two nested case-control study populations in women with a family history of breast and/or ovarian cancer (2,138 ovarian cancers, 85,240 controls) and women without (10,730 ovarian cancers, 429,200 controls). The overall and histology-specific associations were assessed with conditional logistic regression. The country-specific estimates were combined based on a fixed-effect assumption. RESULTS: Multiparity, hysterectomy, tubal ligation, salpingectomy, and oral contraceptive (OC) use were associated with a reduced risk of ovarian cancer in both women with and without a family history, while endometriosis and menopausal hormone treatment (MHT) were associated with increased risk. Multiparity and OC use presented protective effects across all histologic subtypes except mucinous ovarian cancer which was not associated with OC use. MHT increased the risk of serous ovarian cancer but decreased the risk of the mucinous and clear cell cancers. Endometriosis was especially related to an increased risk of endometrioid and clear cell ovarian cancer. CONCLUSION: Factors associated with a decreased ovarian cancer risk were similar between women with and without a family history of breast and/or ovarian cancer. Given the higher baseline risk for women with a family history, special attention should be paid to risk factors like endometriosis and nulliparity in this high-risk population.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 nonlocalized 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.

The association of reproductive factors with risk of non-epithelial ovarian cancer and comparison with serous ovarian cancer.

OBJECTIVE: To examine the association between reproductive factors and risk of non-epithelial ovarian cancer and to compare the associations with those in serous ovarian cancer. METHODS: From the Danish Cancer Registry, we identified all ovarian cancer cases (≥20 years old at diagnosis) of germ cell (n = 188), sex cord-stromal (n = 116), or serous (n = 4854) histology during 1982-2016. For each case, 15 age-matched female controls were selected with risk set sampling. Reproductive history was obtained from nationwide registries. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between reproductive factors and the three ovarian cancer types. RESULTS: Compared with nulliparity, ever giving birth was associated with increased odds for germ cell tumors (OR = 1.28, 95% CI: 0.85-1.93) and decreased odds for sex cord-stromal (OR = 0.74, 95% CI: 0.44-1.26) and serous tumors (OR = 0.70, 95% CI: 0.64-0.76). Infertility decreased odds for germ cell tumors (OR = 0.63, 95% CI: 0.23-1.76) but increased odds for sex cord-stromal tumors (OR = 2.20, 95% CI: 0.89-5.43) and serous tumors (OR = 1.97, 95% CI: 1.69-2.30). Finally, use of oral contraceptives decreased the odds for all three tumor types (germ cell: OR = 0.50, 95% CI: 0.29-0.87; sex cord-stromal: OR = 0.40, 95% CI: 0.13-1.22; serous: OR = 0.50, 95% CI: 0.40-0.62). CONCLUSIONS: Reproductive factors affected the risk of sex cord-stromal and serous ovarian cancer similarly with decreased risk associated with parity and use of oral contraceptives. Oral contraceptives also seemed to decrease the risk of germ cell tumors, whereas parity was associated with increased risk.

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.

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.

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.