Prevalence of high risk genital papillomaviruses in the Belgian female population determined by fast multiplex polymerase chain reaction

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.

Persistent human papillomavirus infection and smoking increase risk of failure of treatment of cervical intraepithelial neoplasia (CIN)

Women with abnormal smears have an increased risk of developing cervical cancer. During the 8 years following conservative treatment of cervical intraepithelial neoplasia (CIN), their risk of invasive cervical cancer is about 5 times greater than that of the general population. Human papillomavirus (HPV) has been associated with the natural history of both CIN and cervical cancer. To date, there have been no published reports on the predictive value of HPV testing in the treatment outcome of CIN. A prospective, multi-center, cohort study was conducted on women in the Northwest of England who were attending for treatment of CIN. They were asked to complete a questionnaire, which included a detailed smoking history. Pre- and post-treatment HPV testing was performed on cervical biopsies and cervical swab, being taken with the first follow-up smear at 6 months. A nested case-control analysis was performed, cases being defined as women who developed CIN within the 2 years of treatment and controls being sampled from those who did not experience treatment failure within 2 years. Multiple conditional logistic regression is used to study the factors associated with treatment failure of CIN. The cohort included 958 women of whom 77 (8%) experienced treatment failure (cases). Two controls were matched to each case (154). Smoking status was significantly associated with CIN treatment failure(p= 0.0013). Current smokers had a 3-fold increased risk of treatment failure of CIN as compared to non-smokers (95% CI 1.65 to 5.91). Five hundred twenty-five women underwent HPV sampling following treatment, of whom 47 (8.9%) developed further CIN. Post-treatment positive HPV testing was found to be strongly associated with treatment failure of CIN (OR 23.3; 95% CI 3.15-172.1). In 11/45 cases with negative smear at first follow-up, the HPV test was positive. The combination of both HPV and cytology in the first follow-up visit predicted treatment failure in 72% of the cases. Cigarette smoking is a factor, which, independently of HPV infection, influences the treatment outcome of CIN. Smokers and those who are HPV positive during follow-up appear to require longer, more intensive follow-up. HPV testing requires careful consideration as part of routine follow-up protocol following treatment of CIN.

Natural history of cervical human papillomavirus infection in young women: a longitudinal cohort study

BACKGROUND

Laboratory and epidemiological research suggests an association between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN). We studied the natural history of incident cervical HPV infection and its relation to the development of CIN.

METHODS

We recruited 2011 women aged 15-19 years who had recently become sexually active. We took a cervical smear every 6 months and stored samples for virological analysis. We immediately referred all women with any cytological abnormality for colposcopic assessment, but postponed treatment until there was histological evidence of progression to high-grade CIN.

FINDINGS

In 1075 women who were cytologically normal and HPV negative at recruitment, the cumulative risk at 3 years of any HPV infection was 44% (95% CI 40-48): HPV 16 was the most common type. The cumulative risk at 3 years of detecting an HPV type not present in the first positive sample was 26% (20-32). 246 women had an abnormal smear during follow-up, of whom 28 progressed to high-grade CIN. The risk of high-grade CIN was greatest in women who tested positive for HPV 16 (risk ratio 8.5 [3.7-19.2]); this risk was maximum 6-12 months after first detection of HPV 16. All HPV types under consideration were associated with cytologically abnormal smears. Although abnormality was significantly less likely to be associated with low-viral-load samples, the cumulative risk at 3 years of a high-viral-load sample after a low-viral-load sample was 45% (95% CI 35-56). Five women who progressed to high-grade CIN consistently tested negative for HPV.

INTERPRETATION

Our findings suggest that attempts to exploit the association between cervical neoplasia and HPV infection to improve effectiveness of cervical screening programmes might be undermined by the limited inferences that can be drawn from the characterisation of a woman's HPV status at a single point in time, and the short lead time gained by its detection.

A study of anal intraepithelial neoplasia in HIV positive homosexual men

OBJECTIVES

To determine the prevalence of high grade anal intraepithelial neoplasia (HGAIN), the value of anal cytology in screening for HGAIN, and the characterisation of epidemiological factors and human papillomavirus (HPV) types.

METHODS

Prospective cohort study of HIV positive homosexual men. Subjects were interviewed, underwent STD, anal cytological, and HPV screening at enrolment and at subsequent follow up visits with anoscopy and biopsy at the final visit. 57 enrolled, average CD4 count 273 x 10(6)/l (10-588); 41 completed the cytological surveillance over the follow up period (181 visits, average follow up 17 months), 38 of these had anoscopy and anal biopsy.

RESULTS

Oncogenic HPV types were detected in 84% and high grade dyskaryosis in 10.5% (6/57) at enrollment. There was a 70% incidence of high grade dyskaryosis during follow up in patients with negative/warty or low grade dyskaryosis at enrollment. Anoscopy correlated with histology in high grade AIN lesions (sensitivity 91%, specificity 54%) and cytology was 78% sensitive (18/23) for HGAIN on biopsy.

CONCLUSIONS

AIN and infection with multiple oncogenic HPV types are very common among immunosuppressed HIV positive homosexual men. Apparent progression from low to high grade cytological changes occurred over a short follow up period, with no cases of carcinoma. All 23 cases of HGAIN were predicted by cytology and/or anoscopy. Future studies focusing on the risk of progression to carcinoma are needed before applying anal cytology as a screening tool for AIN in this population.

Genital papillomavirus in Greek women with high-grade cervical intraepithelial neoplasia and cervical carcinoma

Fifty biopsies from high-grade squamous intraepithelial lesions (HG-SIL) and 14 cervical carcinoma biopsies from Greek women were screened for the presence of human papillomavirus (HPV) DNA sequences by Southern blot hybridization and by the polymerase chain reaction (PCR) for the presence of different HPV types. In high-grade SIL, HPV DNA sequences were detected in 44 of 50 biopsies with the following distribution: 36% HPV 16, 12% HPV 18, 6% HPV 31, 6% HPV 33, 4% HPV 51, and 24% unclassified HPV types. In cervical carcinoma biopsies, 13 of 14 specimens were positive for HPV DNA sequences. Six biopsies were positive for HPV 16, three were positive for HPV 18, and four contained unclassified HPV types. Overall, of the total 64 biopsies, 57 (89%) were positive for HPV DNA sequences. Of these, Southern blot hybridization alone detected HPV DNA sequences in 39 cases, whereas by PCR 18 additional specimens were found to be positive for HPV. Among the HPV 16-positive biopsies, two samples produced a Pstl banding pattern very similar but not identical to that of HPV 16 prototype and were referred to as HPV 16 isolates. One HPV 16 isolate appears to carry a mutation within the carboxy-terminal half of the L2 gene that results in the loss of a Pstl site. The other HPV 16 isolate had a similar Pstl banding pattern to that previously reported as HPV 16 "variant" found in Cape Town [Williamson et al., 1989, Journal of Medical Virology 28: 146-149, 1994, Journal of Medical Virology 43: 231-237.] and in Italy [Li Vigni et al., 1994, 2nd International Congress of Papillomavirus in Human Pathology (Abstracts), p 100.].

Human papilloma virus types in routine cytological screening and at colposcopic examinations

Certain types of human papillomaviruses (HPV) play a crucial role in the development of anogenital cellular dysplasia and cancer. We have searched for a broad spectrum of HPV-types by PCR in cervical cell samples from 230 women aged 20-29 years enrolled at routine gynecological health control and 506 women referred to colposcopy due to suspected cytological changes. Thirteen percent of the health control women had HPV DNA of identified types. Half of the colposcopy patients showed benign histology with corresponding HPV DNA prevalence of 18%, while among the patients with cervical intraepithelial neoplasia between 61% and 78% had HPV DNA. Among both women with normal cytology or histology and those with various degrees of cervical dysplasia, cancer-related HPV types represented about 85% of the types found. The strong correlation between HPV infections and development of cervical dysplasia is an argument for HPV DNA testing of certain patient groups.

Using the polymerase chain reaction to genotype human papillomavirus DNAs in samples containing multiple HPVs may produce inaccurate results

Compared with other laboratory techniques, the polymerase chain reaction (PCR) is a simple, rapid, sensitive method for detecting human papillomavirus (HPV) DNA in cervical samples. However, since many cervical samples contain multiple HPV types, we decided to investigate whether PCR results from such samples accurately reflected the relative amounts of each HPV type present. Theoretical calculations of product accumulation when multiple DNAs with different amplification efficiencies are present in the same sample were done. In addition a set of samples in which cloned HPV DNAs were mixed in varying proportions prior to PCR was tested. Finally, four clinical samples containing multiple HPV types by hybridization assays were subjected to PCR, using two different primer sets. Each of these lines of investigation showed that selective amplification of one HPV DNA over another can occur when mixed HPV types are present. This effect may lead to inaccurate information regarding both types and relative amounts of HPV DNAs in samples containing multiple HPV types. A protocol to avoid this problem is described.

High-risk genital papillomaviruses and degree of dysplastic changes in the cervix: a prospective study by fast multiplex polymerase chain reaction in Belgium

The epidemiologic studies with the least selection bias do not support the hypothesis that HPV types 16 and/or 18 are strongly associated with cervical cancer. In this preliminary report, we describe our findings regarding type 16, 18, and 33 detection rates in 323 normal and 71 dysplastic or neoplastic cervical scrapes using fast multiplex PCR. This modified PCR technique has been shown to be the most sensitive, specific, and reproducible DNA detection method for large epidemiologic studies. The results indicate a high relative risk of increasingly severe cervical abnormality associated with the presence of high-risk HPV DNA. The analysis of the prevalence and age data according to CIN status by non-parametric statistic tests highlights the importance of other factors inversely correlated with age in the cervical transformation process.