Christian Munk

Long term predictive values of cytology and human papillomavirus testing in cervical cancer screening: joint European cohort study.

Objective To obtain large scale and generalisable data on the long term predictive value of cytology and human papillomavirus (HPV) testing for development of cervical intraepithelial neoplasia grade 3 or cancer (CIN3+). Design Multinational cohort study with joint database analysis. Setting Seven primary HPV screening studies in six European countries. Participants 24 295 women attending cervical screening enrolled into HPV screening trials who had at least one cervical cytology or histopathology examination during follow-up. Main outcome measure Long term cumulative incidence of CIN3+. Results The cumulative incidence rate of CIN3+ after six years was considerably lower among women negative for HPV at baseline (0.27%, 95% confidence interval 0.12% to 0.45%) than among women with negative results on cytology (0.97%, 0.53% to 1.34%)). By comparison, the cumulative incidence rate for women with negative cytology results at the most commonly recommended screening interval in Europe (three years) was 0.51% (0.23% to 0.77%). The cumulative incidence rate among women with negative cytology results who were positive for HPV increased continuously over time, reaching 10% at six years, whereas the rate among women with positive cytology results who were negative for HPV remained below 3%. Conclusions A consistently low six year cumulative incidence rate of CIN3+ among women negative for HPV suggests that cervical screening strategies in which women are screened for HPV every six years are safe and effective.

Long-term Absolute Risk of Cervical Intraepithelial Neoplasia Grade 3 or Worse Following Human Papillomavirus Infection: Role of Persistence

BACKGROUND Infection with high-risk human papillomavirus (HPV) is the main cause of high-grade cervical intraepithelial neoplasia (CIN) and cancer. It has been suggested that information about high-risk HPV type-specific infection might make cervical cancer screening more effective. Persistent HPV infection could also be a useful screening marker. We estimated the long-term risk of high-grade CIN after one-time detection of high-risk HPV DNA and after persistent infection with individual high-risk HPV types. METHODS A cohort of 8656 women from the general population of Denmark was examined twice, 2 years apart (first study examination: May 15, 1991, to January 31, 1993; second study examination: October 1, 1993, to January 31, 1995). The women underwent a gynecological examination and cervical cytology and had swabs taken for HPV DNA analysis by the Hybrid Capture 2 and line probe assays. The women were followed up through the nationwide Danish Pathology Data Bank for cervical neoplasia for up to 13.4 years. The absolute risk of developing cervical lesions before a given time was estimated as a function of time. RESULTS For women with normal cytological findings who were concurrently HPV16 DNA positive at the second examination, the estimated probability of developing CIN grade 3 (CIN3) or worse within 12 years of follow-up was 26.7% (95% confidence interval [CI] = 21.1% to 31.8%). The corresponding risks among those infected with HPV18 was 19.1% (95% CI = 10.4% to 27.3%), with HPV31 was 14.3% (95% CI = 9.1% to 19.4%), and with HPV33 was 14.9% (95% CI = 7.9% to 21.1%). The absolute risk of CIN3 or worse after infection with high-risk HPV types other than HPV16, HPV18, HPV31, or HPV33 was 6.0% (95% CI = 3.8% to 8.3%). The estimated absolute risk for CIN3 or cancer within 12 years of the second examination among women who were HPV16 DNA positive at both examinations was 47.4% (95% CI = 34.9% to 57.5%); by contrast, the risk of CIN3 or worse following a negative Hybrid Capture 2 test was 3.0% (95% CI = 2.5% to 3.5%). CONCLUSION HPV16, HPV18, HPV31, and HPV33 infection and especially HPV16 persistence were associated with high absolute risks for progression to high-grade cervical lesions. The results indicate the potential value of genotyping in cervical cancer screening. Given that HPV DNA-negative women retained their low risk of CIN3 or worse for many years, frequent screening of these women may be unnecessary.

The Burden of Genital Warts: A Study of Nearly 70,000 Women from the General Female Population in the 4 Nordic Countries

OBJECTIVE To assess the burden and correlates of genital warts in women. METHODS We conducted a population-based cross-sectional study in 69,147 women (18-45 years of age) randomly chosen from the general population in Denmark, Iceland, Norway, and Sweden. Information on clinically diagnosed genital warts and lifestyle habits was collected using a questionnaire. RESULTS Overall, 10.6% reported ever having had clinically diagnosed genital warts. In addition, 1.3% reported having experienced genital warts within the past 12 months. The cumulative incidence for different birth cohorts, estimated on the basis of age at first diagnosis of genital warts, increased with each subsequent younger birth cohort (P<.01). The lifetime number of sex partners was strongly correlated with a history of genital warts (odds ratio for > or =15 partners vs. 1 partner, 9.45 [95% confidence interval, 7.89-11.30]). The likelihood of reporting genital warts also increased with a history of sexually transmitted disease, use of hormonal contraceptives, use of condoms, smoking, and higher education. CONCLUSIONS The data suggest that 1 in 10 women in the Nordic countries experience genital warts before the age of 45 years, with an increasing occurrence in younger birth cohorts. These data are important for developing and evaluating strategies (e.g., human papillomavirus [HPV] vaccination) to control and prevent HPV infection and disease in the population.

The Absolute Risk of Cervical Abnormalities in High-risk Human Papillomavirus–Positive, Cytologically Normal Women Over a 10-Year Period

In spite of the success of cervical cytology as a cancer-screening tool, it has important limitations, and human papillomavirus (HPV) testing may be valuable in future screening. The majority of women in screened populations, who test HPV positive, will have a concurrent normal smear, and we need more information about the risk for subsequent high-grade cervical lesions in these women. We examined 8,656 younger women (22-32 years old) and 1,578 older women (40-50 years old) who were followed for development of cervical neoplasia (cytology and/or histology) through the Danish Pathology Data Bank. We estimated the proportion of women developing cervical lesions of different types before a given time point as a function of time. Among women with normal cytology and positive high-risk Hybrid Capture 2 (HC2) test, 17.7% and 24.5% of younger and older women, respectively, had a subsequent abnormal Pap smear within 5 years. The risk of CIN3 or cancer within 10 years among younger women with positive HC2 test was 13.6% (10.9-16.2) and 21.2% (2.7-36.1) among older women. An analysis among younger women also being HC2-positive 2 years before baseline showed a subsequent 10-year risk of > or =CIN3 of 18% (14.6-21.5). Among older women where HPV may be added to general screening, the estimated absolute risk of > or =CIN3 in HC2-positive women was more than 20% within 10 years. These results indicate that even a single positive HPV test in cytologically negative women is substantially predictive of high-grade CIN and suggest that HC2 testing can help stratify women into different risk categories.

Acquisition and persistence of human papillomavirus infection in younger men: a prospective follow-up study among Danish soldiers

No data is yet available on incidence or persistence of human papillomavirus (HPV) infection in men. We enrolled 374 younger male conscripts (18-29 years) in a prospective study, and they were examined twice with an interval of 6 to 8 months. Data collection included a questionnaire and a sample of cells from the penis for HPV detection using PCR. In addition, the presence of Chlamydia trachomatis DNA was assessed in urine samples by means of PCR. The HPV prevalence at the first and second examinations was 33.8% and 31.9%, respectively. The acquisition rate of HPV (overall) during follow-up was 13.8%, and nearly one fourth of the participants were HPV positive at both examinations. Number of sex partners during follow-up was the most important risk factor for acquiring HPV (odds ratio, 17.2; 95% confidence interval, 4.6-64.7, for ≥3 partners versus ≤1 partner). In contrast, acquisition of a new HPV type in initially HPV-positive men was strongly related to having multiple HPV types at enrollment (OR, 4.1; 95% confidence interval, 1.4-12.3). This was also the most important risk factor for HPV persistence together with current smoking and having a high-risk HPV type at enrollment. This is the first study to assess risk factors for acquisition and persistence of HPV. The sexually transmitted nature of the infection is confirmed, and the data point to an important role of having multiple HPV types for persistence.

Trends in head and neck cancer incidence in Denmark, 1978–2007: Focus on human papillomavirus associated sites

The aim of our study was to assess the overall trends in the incidence of head‐and‐neck cancer (HNC) among Danish men and women in 1978–2007, to describe the distribution and incidences of HNCs at different anatomical sites, and to determine whether the incidence of human papillomavirus (HPV)‐associated cancers is increasing. Data were extracted from the nationwide Cancer Registry database. To assess the possible impact of HPV infection, the sites of squamous cell carcinomas were categorized as HPV‐associated, potentially HPV‐associated or HPV‐unrelated. In total, 26,474 incident cases were identified and the overall incidence increased throughout the period. Significantly increasing incidence rates were notably seen for tumors in the oral cavity (2.2% per year), tonsils (4.8% per year), oropharynx (3.5% per year) and hypopharynx (4.4% per year). A significantly decreasing incidence of lip cancer was observed among men (–5.0% per year). Cancers at HPV‐associated sites (n = 3650) showed strongly increasing incidence rates, primarily in individuals < 60 years. In contrast, HNCs at sites not related to HPV infection showed a significant decrease (in men) or virtually no change in incidence (in women). Our results suggest a marked impact of HPV infection on the epidemiology of HNCs in Denmark. HPV16 is the type most often found in HNCs; thus, the recent introduction of vaccination against HPV may in the future prevent HPV‐associated cancers of the head and neck.

Population‐based prevalence, type‐ and age‐specific distribution of HPV in women before introduction of an HPV‐vaccination program in Denmark

Knowledge about the prevalence of human papillomavirus (HPV) on a population level is important. We conducted a large population‐based study in Denmark to determine the overall and age‐specific HPV prevalence, and HPV type distribution in women. Liquid‐based cytology samples (SurePath®) were collected consecutively. HPV testing was performed with Hybrid Capture 2 (HC2; Digene) (high‐risk and low‐risk probes), and LiPA (Innogenetics) was used for genotyping. We analyzed samples from 11,617 women; 94.0% had normal cytology, 4.3% atypical squamous cells of undetermined significance or low‐grade squamous intraepithelial lesion and 1.6% had high‐grade squamous intraepithelial lesion (HSIL). The HPV prevalence was 26.4% with a peak in women 20–24 years (50.2%) and then decreased without a second peak in older women. Among the youngest women (15–19 years), 14% had HPV 16/18 and 16% had HPV 6/11. Prevalence of high‐risk HPV types increased from 19.2% in women with normal cytology to 100% in women with cervical intraepithelial neoplasia grade 3 (CIN3)/cervical cancer. HPV 16 was the most prevalent type (6.0% of all women), and was also the most prevalent in women with HSIL (35.1%) and CIN3 (53.2%). Other common HPV types in women with CIN3 included HPV 52, 51, 31, 33 and 18. HPV 16/18 alone was present in 23% of CIN3 lesions and 67% of cervical cancers, and HPV 16/18 together with other high‐risk HPV types was present in 41% of CIN3 lesions. This suggests that an efficacious HPV 16/18 vaccine will have a substantial preventive potential in the general female population.

Comparison of the performance of different HPV genotyping methods for detecting genital HPV types

Classification of high‐risk HPV types for cervical cancer screening depends on epidemiological studies defining HPV type‐specific risk. The genotyping tests that are used, are however, not uniform with regard to type‐specific detection rates making comparisons between different studies difficult. To overcome the lack of a “gold standard” four tests were evaluated crosswise using 824 cervical smears pretested by HC2. The tests evaluated were the L1‐PCR‐based assays PGMY09/11 LBA, HPV DNA Chip and SPF LiPA and an E1 consensus PCR followed by cycle sequencing (E1‐PCR). A subset of 265 samples was tested in addition with the GP5+/6+ reverse line blot assay. Differences were noted in the sensitivity and range for specific HPV types, e.g. with detection rates for HPV53 ranging from 2.3% to 11.6%. HPV16 was the most prevalent type detected by all tests except for the SPF‐10 LiPa, which detected HPV31 more often. Kappa values calculated ranged from poor (k = 0.20) to intermediate (k = 0.54) for HPV positivity, but were higher for high‐risk type positivity (k = 0.31–0.61) and best for recognition of HPV16 (k = 0.53–0.72). The analytical sensitivity of the tests ranged between 15% and 97% for individual types and specificity was highly dependent on which test system was used as “gold standard” for the analysis. The results of histology were used for calculation of clinical sensitivity and specificity. E1‐PCR, PGMY09/11 LBA and SPF‐10 LiPA had a high clinical sensitivity (>95%) for the detection of cervical intraepithelial neoplasia 2 or higher, whereas the HPV DNA Chip reached only 84.1%. J. Med. Virol. 80: 1264–1274, 2008.

Type-specific HPV infection and multiple HPV types: prevalence and risk factor profile in nearly 12,000 younger and older Danish women.

Objectives: Human papillomavirus (HPV) is considered a necessary cause of cervical cancer. The aim of the current study was to determine the burden of HPV infection among randomly sampled Danish women before the vaccine against HPV is implemented. Further we assessed the risk factor profile for prevalent high risk (HR) HPV infection and infection with multiple HR HPV types. Methods: In the present cross-sectional study, we used baseline data from a population-based cohort study where participants were interviewed and had a gynecological examination. Cervical samples were analyzed for HR HPV using Hybrid capture 2 in 10,544 women aged 20–29 years and 1443 women aged 40–50 years. Genotyping was performed using LiPA. Results: The prevalence of HR HPV was 17.9% and 4.4% in women aged 20–29 years and 40–50 years, respectively. HPV16 was the most common HR type overall and among women with abnormal cytology. Multiple HPV types were highly prevalent, notably in the younger cohort. Lifetime number of sexual partners was the main risk factor for HR HPV infection (adj. OR = 2.8 and OR = 3.4 for ≥15 partners vs. ≤4 in respectively younger and older women), whereas number of recent sexual partners was only associated with risk in younger women. Number of partners, oral contraceptive use and self-reported chlamydia infection increased the risk of having multiple HR HPV types (compared to having a single HR HPV type). Conclusions: HR HPV infection was common among younger women, with HPV16 as the predominant type. We confirmed the importance of sexual activity for the risk of HR HPV infection. In addition, we found that sexual behavior also play an important role for the risk of having multiple HR HPV types.

Comparison of Three Commercially Available Peptide-Based Immunoglobulin G (IgG) and IgA Assays to Microimmunofluorescence Assay for Detection of Chlamydia trachomatis Antibodies

ABSTRACT Three commercially available, peptide-based enzyme-linked immunosorbent assay (ELISA) systems (Chlamydia trachomatis IgG and IgA EIA [CT-EIA; Labsystems OY, Helsinki, Finland], SeroCT IgG and IgA [SeroCT; Savyon Diagnostics Ltd., Ashdod, Israel], and Chlamydia trachomatis IgG and IgA pELISA [CT pELISA; Medac, Wedel, Germany]) were evaluated for the detection of serum immunoglobulin G (IgG) and IgA antibodies specific for Chlamydia trachomatis and compared to the “gold standard” assay, the microimmunofluorescence (MIF) assay. Serological responses were analyzed in 149 women aged 20 to 30 years. Cervical swabs obtained from these women were examined for C. trachomatis by PCR, and 43 were found to be positive. The overall seroprevalence rates detected by CT-EIA, SeroCT, CT pELISA, and the MIF assay were 42, 42, 35, and 39%, respectively, for IgG and 7, 7, 3, and 7%, respectively, for IgA. The IgG seroprevalence rates for the PCR-positive women were two to three times higher than those for the PCR-negative women, i.e., 72 versus 29%, 72 versus 29%, 47 versus 26%, and 74 versus 25% for CT-EIA, SeroCT, CT pELISA, and the MIF assay, respectively. After discrepancy analysis, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the IgG assays; for CT-EIA they were 84.7, 98.6, 98.4, and 86.7%, respectively; for CT pELISA they were 71.4, 97.3, 96.2, and 78.3%, respectively; for SeroCT they were 84.7, 98.6, 98.4, and 86.3%, respectively; and for the MIF assay they were 79.2, 83.1, 98.3, and 83.1%, respectively. In conclusion, these peptide-based ELISA systems for the serological detection of C. trachomatis infection performed as well as the MIF assay. Since these tests are less time-consuming, less expensive, and easier to perform than the MIF assay, they might be useful in the serodiagnosis of chlamydial infection.