Risk factors for HPV detection in archival Pap smears. A population-based study from Greenland and Denmark

Developing and validating the Personal Risk of Oncogenic Human Papillomavirus infection score in US Women

BACKGROUND

Determining risk scores for genital high-risk human papillomavirus (HRHPV) infection in women will support more efficient cervical cancer screening strategies.

OBJECTIVE

We developed and validated point scores to predict the likelihood of any genital HRHPV infection in women.

METHODS

We conducted the cross-sectional analysis in 2017 and used data from the 2005-14 US National Health and Nutrition Examination Survey (7337 women aged 25-59 years; 6300 women aged 30-59 years). Predictors were reproductive health practices, risk behaviors and demographic variables. The outcome was a positive result for any of the 21 genital HRHPV genotypes. The 2005-12 cohorts were used as training and testing sets to develop scores that best classified women into three risk groups: low risk (<20%), average risk (20-30%) and high risk (>30%). The 2013-14 cohort was used to validate the final scores.

RESULTS

Two-point scores with six self-reported variables were created to predict any HRHPV risks for the two age groups: the Personal Risk of Oncogenic HPV (PRO-HPV25) for women aged 25-59 years old and PRO-HPV30 for women aged 30-59 years old. The scores were successfully prospectively validated, with good calibration with regards to the predicted and observed rates of HRHPV infection. The scores had fair discrimination (c-statistics: 0.67-0.68).

CONCLUSION

The PRO-HPV risk scores can identify groups at low, average and high risk of genital HRHPV infection. This information can be used to prioritize women for cervical cancer screening in low-resource settings or to personalize screening intervals.

Age-specific prevalence of infection with human papillomavirus in females: a global review

PURPOSE

Global data on age-specific prevalence of human papillomavirus (HPV) infection overall, and for high-risk HPV types 16 and 18, are essential for the future implementation of HPV prophylactic vaccines for cervical cancer prevention.

METHODS

A systematic review of peer-reviewed publications was conducted to summarize worldwide data on genital HPV-DNA prevalence in women. Studies with clear descriptions of polymerase chain reaction or hybrid capture detection assays were included.

RESULTS

A total of 346,160 women were included in 375 studies. Of 134 studies with age-stratified HPV prevalence data (116 low sexual risk populations, 18 high sexual risk populations), over 50% were from Europe and the Middle East (38%) and North America (19%), with smaller proportions from Asia and Australia (21%), Central and South America (11%), and Africa (10%). Across all geographical regions, data on HPV prevalence were generally limited to women over 18 years of age. Consistently across studies, HPV infection prevalence decreased with increasing age from a peak prevalence in younger women (< or =25 years of age). In middle-aged women (35-50 years), maximum HPV prevalence differed across geographical regions: Africa (approximately 20%), Asia/Australia (approximately 15%), Central and South America (approximately 20%), North America (approximately 20%), Southern Europe/Middle East (approximately 15%), and Northern Europe (approximately 15%). Inconsistent trends in HPV prevalence by age were noted in older women, with a decrease or plateau of HPV prevalence in older ages in most studies, whereas others showed an increase of HPV prevalence in older ages. Similar trends of HPV 16 and/or 18 prevalence by age were noted among 12 populations with available data.

DISCUSSION

Genital HPV infection in women is predominantly acquired in adolescence, and peak prevalence in middle-aged women appears to differ across geographical regions. Worldwide variations in HPV prevalence across age appear to largely reflect differences in sexual behavior across geographical regions. Further studies of HPV prevalence in adolescents are needed for all geographic regions.

Cancer risk among patients with condylomata acuminata

Condylomata acuminata have been shown to increase the risk of anogenital cancers. However, previous studies have been of limited sample size and/or short follow-up duration, which prevent precise estimates of long-term excess risk, especially for specific cancer sites. We estimated the risk of specific cancers in a large cohort of hospitalized patients with condylomata acuminata, as recorded in the Swedish Inpatient Register between 1965 and 1999. Altogether, 10,971 patients (1,685 men and 9,286 women) were followed through 1999 for a median of 13 years. The standardized incidence ratio (SIR)--the ratio of the observed number of cancers to the number expected on the basis of the incidence in the Swedish population at large--was used as a measure of relative risk. After excluding the first-year of follow-up, we observed 43 cases of anogenital cancer in women, and 7 cases in men. Risks were elevated for cancers of the vulva (N = 13, SIR = 10.2, 95% confidence interval (CI) = 5.4-17.4), vagina (N = 4, SIR = 12.0, 95% CI = 3.3-30.7) and penis (N = 5, SIR = 21.9, 95% CI = 7.1-51.2). There was a moderate excess risk of cervical cancer in situ (N = 259, SIR = 1.9, 95% CI = 1.7-2.1), but not invasive cervical cancer. Excess risks of esophageal, buccal cavity, nonmelanoma skin, lung and bladder cancers, and Hodgkin and non-Hodgkin lymphoma, were also observed in both men and women. In conclusion, condylomata acuminata are strongly associated with increased risk of cancers of the vulva, vagina, penis and anus, as well as some nonanogenital malignancies, but not invasive cervical cancer.

Are Muslim women less susceptible to oncogenic human papillomavirus infection? A study from rural eastern India

Muslim women are known to have lower incidences of cervical cancer and/or human papillomavirus (HPV) infection. Here we aim to determine any association that may be present between the oncogenic HPV16/18 infections and abnormal cytological lesions along with demographic and other attributes among Indian Muslim women (n = 478) and compare with the neighboring Hindus (n = 534) from a prospective cohort study. Agewise distribution of both subject-groups is similar. HPV16/18 infection is present in 9.6% Muslims and 7.5% Hindu women. Jointly atypical cells of undetermined significance (a typical cells of undetermined significance) and HPV16/18 are present in seven Muslim and two Hindu women. No high squamous intraepithelial lesions or cervical cancer is detected at the baseline. HPV16/18 infections show trends that varied with age, a nonlinear trend among Muslim women. In Hindu women the prevalence is highest at age < or =24 years, which linearly drops with increasing age. Abnormal cytology increases significantly in both religion-groups with increasing age. The data show that these Indian Muslim women are equally susceptible to HPV16/18 infection and for the development of abnormal cytology. There is a paucity in epidemiological data, which justifies the need to screen women of all religions for cervical cancer (that includes oncogenic HPV testing).

Toxicological evaluation of nitrosamines in condoms

Volatile N-nitrosamines have been found in rubber products including gloves, balloons, toys, baby bottle teats, soothers, and condoms. N-Nitrosamines are potent carcinogens, and therefore, European legislation has limited the release of N-nitrosamines and N-nitrosatable compounds in teats and soothers to 0.01-0.1 mg/kg rubber, respectively. Previously, endogenous nitrosamine formation in the vagina has been suggested as a cause of cervical cancer. It was speculated that exogenous N-nitrosamines and N-nitrosatable compounds from condoms may also lead to genital cancer. Therefore, we reviewed the literature and calculated the risk for the induction of tumors by nitrosamines from condoms. In vitro Biaudet et al. (1997) found up to 88 ng nitrosatable compounds migrating from condoms to cervical mucous within 24 hrs. During sexual intercourse about 0.6 ng may migrate in the female genital mucous membranes because of the short contact to the condom, e.g. 10 min. Comparable amounts of nitrosamines may also migrate in the penile skin. Estimating 1500 contacts to condoms during lifetime (50 condoms/year for 30 years) this may result in the adsorption of up to 0.9 microgram nitrosamines in total. Animal studies in Syrian hamsters showed the induction of local and/or systemic tumors, in particular liver tumors, after topical application of nitrosamines to the skin or mucous membrane at a total dose of about 1 g. This dose exceeds the dose to be expected from contact with condoms by more than 1 million. Also, epidemiological studies do not support a role for condoms in the induction of cancer. The incidence of cervical cancer and liver tumors is high in developing countries, where condoms are seldom used. In addition, humans are regularly exposed to nitrosamines from food and tobacco smoke at a dose which is 1,000 to 10,000 fold higher than expected from condom use. In summary, the risk for the induction of tumors from nitrosamines in condoms is very low.

The relationship of human papillomavirus (HPV) detection to pap smear classification of cervical-scraped cells in asymptomatic women in northeast Thailand

OBJECTIVE

To correlate the detection of human papillomavirus (HPV) with the Pap smear classification of cervical-scraped cells from asymptomatic women living in northeast Thailand.

METHODS

A total of 260 asymptomatic women attending the Obstetrics and Gynecology's Outpatient Clinic, Srinagarind Hospital, Thailand, were interviewed for risk factors and cervical scrapes were taken. The cells were examined by Pap smear for cytological changes and by PCR for HPV DNAs--nononcogenic (HPVs 6 and 11) and oncogenic (HPVs 16, 18 and 33) types. Cervical biopsies were taken from women with abnormal Pap smears for histological examination.

RESULTS

Of the 260 cervical smear samples, the cervical cells were classified as normal and abnormal in 174 and 86, respectively. Twenty-three percent of all samples were positive for overall HPV DNA. HPV DNAs (mostly HPVs 6 and 11) were detected in 21% of normal cells, and the higher detection rate (27%) for HPV DNA in abnormal cells gradually increased in severity from 16% in Class 3 to 35 and 60% in Classes 4 and 5, respectively. Histologically 46, 90 and 100% of HPV detection was associated with CIS, SCC and adenocarcinoma, respectively. Almost all of the HPV DNAs detected were types 16, 18 or 33. There was no significant association between HPV infection and reproduction history, sexual behavior and demographic variables.

CONCLUSION

We speculated that an abnormal Pap smear and the detection of an oncogenic type HPV may indicate the presence of neoplastic cells in asymptomatic woman who might be at risk for the development of cervical cancer.

Prediction of high-grade cervical intraepithelial neoplasia in cytologically normal women by human papillomavirus testing

Human papillomavirus (HPV) testing has been suggested for primary screening of cervical cancer. Prediction of future high-grade cervical lesions is crucial for effectiveness and cost. We performed a case control study in a retrospective cohort of women with at least two cervical smears, all but the last one being negative, from the organized cervical screening programme in Florence, Italy. We searched for high-risk HPV in all previous, archival, smears from cases (new histologically confirmed cervical intraepithelial neoplasia (CIN) grade II or worse) and in one previous smear from each control (last smear cytologically normal, matched by age and interval (latency) from last smear). We applied polymerase chain reaction (PCR), and the b-globin gene was used as a DNA preservation marker. High-risk HPV was identified in 71/92 (77.17%) previous smears from 79 cases and 17/332 controls (5.12%). The odds ratio (OR) was 63.76 (95% CI 30.57-132.96). Among cases the proportion of HPV-positive smears declined slightly with increasing latency. Among cases, HPV was found in 81.24% (95% CI 69.93-88.96%) of smears with latency < 4 years and in 67.80% (95% CI 47.72-82.93%) of those taken at longer intervals, up to 6 years. These findings suggest that testing for high-risk HPV allows predicting 80% of CINII/III 3 years before the cytological diagnosis and two thirds 6 years before. They also suggest that testing women negative for high-risk HPV at longer interval and strictly following-up women who are HPV positive could be an effective strategy for cervical cancer screening.

Human papillomavirus infection in Danish female sex workers. Decreasing prevalence with age despite continuously high sexual activity

BACKGROUND

The prevalence of the human papillomavirus (HPV) has been found to decrease with age, but whether this applies to all populations is not clear. Knowledge about the generalizability of this age dependency is important to understand the natural history of the infection, but may also have implications in relation to the use of HPV testing in cervical cancer screening.

GOAL

To study the prevalence and risk factors for HPV infection in a selected population of female sex workers and to compare the results with persons with different sexual habits from two other populations in the same geographic area.

STUDY DESIGN

A case-control study among 188 female sex workers from Copenhagen. Data were obtained by personal interviews. Cervical material was collected by a self-administered lavage kit, and HPV testing was done by means of GP5+/6+ primers based on HPV, polymerase chain reaction, enzyme immunoassay.

RESULTS

Among sex workers, age was the most important risk factor for HPV infection. Number of private sex partners in the last 4 months was also a significant risk factor, and a protective effect of condom use was indicated.

CONCLUSION

The HPV prevalence is declining in sex workers with age despite continuously high sexual activity, most likely indicating that an immune response is acquired over time.