A population-based study of human papillomavirus deoxyribonucleic acid testing for predicting cervical intraepithelial neoplasia

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.

Human papillomavirus testing improves the accuracy of colposcopy in detection of cervical intraepithelial neoplasia

To assess the performance of human papillomavirus (HPV) testing and colposcopy in detection of cervical pathology. A series of 389 women referred for colposcopy due to an abnormal Pap smear had cervical swabs analyzed for oncogenic (high-risk [HR]) HPV types using Hybrid Capture II (HC2) assay. Loop electrical excision procedure cone biopsy (88%) or colposcopic biopsy (11%) was used as the gold standard. Of the atypical squamous cells of undetermined significance (ASCUS) smears, 48% were positive for HR HPV, as compared to 76.3% of low-grade squamous intraepithelial lesions (LSIL) smears. HR HPV was detected in 66.7% and 90% of patients with cervical intraepithelial neoplasia (CIN) 1 and CIN2 (or higher), respectively. The sensitivity of the Pap smear using an ASCUS threshold in detecting high-grade CIN was 94.5% (95% confidence intervals (CI): 91-97%) and that of colposcopy 98.5% (95% CI: 95-99%). The respective specificities were 30% (95% CI: 17-28%) and 35.6% (CI: 29-42%). HC2 test had comparable sensitivity, 90% (95% CI: 85-93%), but higher specificity, 54.3% (95% CI: 47-61%). Combining HC2 test with Pap increased specificity, 66.7% and 41.3% for ASCUS and LSIL cutoff, respectively. The minor-abnormality threshold together with HC2 increased specificity of colposcopy with no changes in sensitivity. High viral load (>100 relative light unit/positive control) was associated with significant disease. HPV DNA testing improves the accuracy of colposcopy in the detection of high-grade CIN in women with ASCUS or LSIL smears.

Role of human papillomavirus (HPV) testing in the follow-up of patients after treatment for cervical precancerous lesions

OBJECTIVE

To evaluate the role of human papillomavirus (HPV) testing in post-treatment follow-up of patients after therapeutic excision of the cervix due to positive screening tests.

STUDY DESIGN

A hospital-based retrospective analysis was performed with prospective collection of patient data of women screened for cervical cancer at a Gynecologic Outpatient Clinic. Patients after therapeutic excision due to positive screening results were identified and followed up with HPV testing and serial cytology.

RESULTS

After 61 treatment for cervicalis intraepithelialis neoplasia (CIN), high-risk HPV infection was detected during the post-treatment follow-up at 18 cases (29.5%), 10 of them had persisting cytological atypia (positive predictive value (PPV): 56%), 5 developed CIN (PPV: 28%). When the HPV test was negative (43 patients) in the post-treatment period, neither CIN nor persisting cytological atypia developed (negative predictive value (NPV): 100%) during 1201 patient months (median 26 months).

CONCLUSIONS

A negative HPV test eliminates the risk of recurrent disease after treatment for CIN.

Moderate variation of the oncogenic potential among high-risk human papillomavirus types in gynecologic patients with cervical abnormalities

The oncogenic potential of human papillomavirus (HPV) infection was assessed by following the disease course in 455 patients who had had a routine diagnostic Hybrid Capture HPV test due to squamous cell abnormalities of the uterine cervix as detected by cytology and/or colposcopy. At entry, 308 patients had cytologic atypia classified as P3 by the Papanicolau classification, 168 had a positive high-risk HPV test, and 23 were infected only with low-risk HPV. The patients were followed-up using the patient registry until the endpoint of histologically diagnosed cervical intraepithelial neoplasia (CIN). High-grade CIN was diagnosed in 75 surgical biopsies. High-risk HPV infection (relative risk: 76.8 CI(95): 23.7-249.5), cytologic atypia (RR: 16.2 CI(95): 3.9-66.6), and age above 35 (RR: 1.99 CI(95): 1.26-3.16) were independent risk factors for high-grade CIN, while the viral load did not predict oncogenic progression (P = 0.47). After PCR-RFLP typing, the high-risk types were classified into groups as follows: (1) types 16 and 18, (2) types 45, 52, and 56, (3) types 31, 33, 35, 51, and 58. The relative risks of high-grade CIN were 119.1 (CI(95): 36.2-390.9) for group 1, 44.4 (CI(95): 9.8-201) for group 2, and 39.7 (CI(95): 10.9-144.8) for group 3, respectively. The risk ratios between the groups of high-risk types were found to differ at most by a factor of 2.98 (corrected P value: 0.007) indicating that the oncogenic potential varies moderately within the high-risk group of HPVs.

Value of human papillomavirus testing after conization by loop electrosurgical excision for high-grade squamous intraepithelial lesions

OBJECTIVE

The aim of the study was to evaluate human papillomavirus (HPV) testing during the follow-up of patients after conization by loop electrosurgical excision for high-grade squamous intraepithelial lesion.

METHODS

A prospective study was conducted on 205 patients who underwent conization for high-grade squamous intraepithelial lesion (CIN 2 or 3). Loop electrosurgical excision procedure (LEEP) was used in all cases. High-risk HPV testing was realized by the Hybrid Capture II system before and 3 months after conization.

RESULTS

Of the 205 patients, 193 (94.1%) were positive for the HPV test before conization. Seventy-one were HPV positive after conization (34.6%). The margins were positive in 36.1%. Residual disease was observed in 27 cases (13.2%). Four patients (2%) developed a recurrence after a mean follow-up of 18.1 months (+/-12). There was no correlation between pretreatment HPV testing and the residual disease or recurrence. Patients with positive margins were significantly more likely to have residual disease than those with negative margins (P < 0.0001). Residual disease was more likely to occur when the posttreatment HPV test was positive (P < 10(-7)). All recurrences were observed in patients with a positive posttreatment HPV test (P < 0.05). Residual disease and recurrence were correctly predicted with a sensitivity of 81 and 100%, respectively, and a negative predictive value of 96 and 100%.

CONCLUSION

Posttreatment HPV testing could be useful in the follow-up of patients after conization. In case of negative posttreatment HPV testing, the frequency of follow-up could be reduced, particularly in those patients with free margins.

Use of human papillomavirus DNA testing to compare equivocal cervical cytologic interpretations in the United States, Scandinavia, and the United Kingdom

BACKGROUND

Human papillomavirus (HPV) DNA testing may be useful in clarifying equivocal cervical cytologic interpretations. One application might be to standardize the meaning of equivocal interpretations from laboratories in various regions. Because international differences may be particularly marked, international comparisons of emerging data will require clear translations of "equivocal" and similar terms.

METHODS

To perform a three-country comparison, the authors selected a morphologically diverse set of 188 conventional Papanicolaou tests initially classified as "squamous atypia" from a study of more than 20,000 women in Portland, Oregon (1989-1990). Previously, five U.S. expert cytopathologists independently interpreted the slides with screening cytotechnologists' marks in place. For this comparison, one British and two Scandinavian reviewers involved in HPV research reviewed the slides after original marks had been removed. The authors compared all eight reviewers' classifications of negative, equivocal, or abnormal in a series of pairwise comparisons using the kappa statistic. They then compared cytologic interpretations with HPV DNA testing.

RESULTS

Oncogenic HPV DNA detection was significantly associated with increasingly abnormal interpretations for each reader. The British reader tended to rate tests as more abnormal than the American pathologists did, whereas the Scandinavians tended to rate tests as more normal. Reference to the HPV DNA standard clarified the tendency of readers to render systematically more or less severe interpretations. For example, the Scandinavian cytologists discounted subtle (often HPV-associated) changes in favor of cytologic certainty, making HPV triage of equivocal tests less applicable there.

CONCLUSIONS

International research on cytopathology, particularly on the possible uses of HPV DNA testing, will require calibration of local cytologic definitions.

Primary screening for human papillomavirus infection

As human papillomavirus infection is now known to be a necessary risk factor for at least 95% of cervical cancers, the medical community has a responsibility to assess and evaluate how this knowledge should best be used for the prevention of cervical cancer. Organized screening strategies combining cytological screening with human papillomavirus testing in older age groups could theoretically be more sensitive than current screening programmes in reducing the incidence of cervical cancer. If it is possible safely to extend the screening interval in human papillomavirus-negative women, such programmes could also both be more effective and more cost-efficient. Although some modelling studies have indicated that this could indeed be the case, evidence from clinical trials evaluating the long-term protective effect of primary human papillomavirus screening is still lacking. The key issues on the research agenda for primary human papillomavirus screening are reviewed.

The role of human papillomavirus in screening for cervical cancer

PURPOSE

To review the options for effectively screening for cervical cancer, including human papilloma virus (HPV) identification, cytologic screening, colposcopy, or a combination approach. Current pathophysiology, diagnostic criteria, treatment approaches, and patient preparation and education related to cervical cancer screening and prevention are also included.

DATA SOURCES

Comprehensive review of current literature, including research and review articles.

CONCLUSION

Because the Papanicolau (Pap) smear is a screening tool, not a diagnostic tool, further studies must be done to identify the actual nature of discovered abnormalities. Of particular concern is the classification of atypical squamous cells of undetermined significance (ASCUS), which may simply indicate inflammation, or may be the first indicator of serious pathology. Following ASCUS Pap smears with HPV screening will allow for a clarification of the best approach to treatment. A screening algorithm supported by a review of the literature is proposed.

IMPLICATIONS FOR PRACTICE

Cervical cancer is a preventable disease caused by certain forms of HPV. Current screening protocols are based on the use of the Pap smear; and in areas where this test is routine and available, morbidity and mortality rates have dropped dramatically. Many women throughout the world and in underserved regions of the U. S. do not have adequate access to routine screening with Pap smear technology. As long as women continue to die needlessly of cervical cancer, more comprehensive and accessible screening methods must be explored. (Cutting the unnecessary worldwide and in the U. S.).

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.

Regular disappearance of the human papillomavirus genome after conization of cervical dysplasia by carbon dioxide laser

OBJECTIVE

We wished to evaluate the effectiveness of treatment of cervical dysplasia by laser conization in relation to persistence of human papillomavirus after treatment.

STUDY DESIGN

Of 203 women referred to colposcopy because of an abnormal Papanicolaou smear, 149 women could be followed up for 3 years. A total of 108 women were treated by carbon dioxide laser excision, 4 women were treated by carbon dioxide laser evaporation, and 37 women were merely followed up. Cervical samples were taken before treatment and at follow-up 3 years later and were analyzed by nested general primer polymerase chain reaction for human papillomavirus deoxyribonucleic acid.

RESULTS

Among women treated by laser conization, 82 (73.2%) had positive results for human papillomavirus deoxyribonucleic acid before treatment. Three women (2.7%) had a positive finding at follow-up, but no woman had the same human papillomavirus type on both occasions. Eighty-eight women had grade 1 to grade 3 cervical intraepithelial neoplasia before treatment, whereas during follow-up only 2 squamous cells atypias were found.

CONCLUSION

The human papillomavirus genome present before treatment was regularly cleared, and there was also no recurrence of dysplasia. The results suggest that human papillomavirus testing is useful for monitoring the efficacy of treatment and that treatment modalities resulting in clearance of human papillomavirus should be favored.

Persistence of human papillomavirus infection after therapeutic conization for CIN 3: is it an alarm for disease recurrence?

OBJECTIVE

The aims of this study were (1) to examine whether HPV DNA is persistently detected in the cervix after therapeutic conization for CIN 3 and (2) to explore whether a patient with persistence of HPV infection is at risk of developing recurrent disease.

METHODS

Of 74 patients referred with CIN 3, 58 who were tested for HPV DNA in the pretreatment cervical lesions were enrolled in the study. After standard therapeutic conization, patients were followed prospectively at the outpatient clinic. Our follow-up protocol was to follow patients without therapeutic intervention as long as they developed no recurrence or recurrence of CIN 1 or 2, while patients who experienced recurrence of CIN 3 were recommended for reconization or hysterectomy. The polymerase chain reaction for detecting HPV DNA was performed using fresh cell samples from the cervix.

RESULTS

In 56 of 58 patients (96.6%), HPV DNAs were detected in their primary cervical lesions prior to conization. With regard to the distribution of HPV types, HPV type 16 family (types 16, 31, and 35) was identified in 28 cases (50.0%), type 18 family (types 18, 33 and 58) in 15 (26.8%), and type X in 18 (32.1%). Up to August 1999, all of the 58 patients have been followed with a mean follow-up period of 31.8 months (range: 12 to 73 months). After treatment, HPV DNA was persistently detected in 11 (19.6%) but negative in 45 (80.4%) of 56 HPV DNA-positive patients. HPV DNA was not detected in both HPV DNA-negative patients. Five of 11 persistently HPV DNA-positive patients (45.5%) developed CIN recurrence, while none of 45 persistently HPV DNA-negative patients did. Thus, there was a significant difference between the recurrence rates of these two groups (P < 0.0001). Both patients who were initially HPV DNA-negative developed no recurrence. Accordingly, the overall recurrence following conservative treatment for CIN 3 was 5 of 58 patients (8.6%).

CONCLUSIONS

Patients with persistent HPV infection after conization for CIN 3 should be especially closely followed because they are at increased risk of developing disease recurrence.

Smoking, diet, pregnancy and oral contraceptive use as risk factors for cervical intra-epithelial neoplasia in relation to human papillomavirus infection

Smoking, nutrition, parity and oral contraceptive use have been reported as major environmental risk factors for cervical cancer. After the discovery of the very strong link between human papillomavirus (HPV) infection and cervical cancer, it is unclear whether the association of these environmental factors with cervical cancer reflect secondary associations attributable to confounding by HPV, if they are independent risk factors or whether they may act as cofactors to HPV infection in cervical carcinogenesis. To investigate this issue, we performed a population-based case-control study in the Vasterbotten county of Northern Sweden of 137 women with high-grade cervical intra-epithelial neoplasia (CIN 2-3) and 253 healthy age-matched women. The women answered a 94-item questionnaire on diet, smoking, oral contraceptive use and sexual history and donated specimens for diagnosis of present HPV infection (nested polymerase chain reaction on cervical brush samples) and for past or present HPV infections (HPV seropositivity). The previously described protective effects of dietary micronutrients were not detected. Pregnancy appeared to be a risk factor in the multivariate analysis (P < 0.0001). Prolonged oral contraceptive use and sexual history were associated with CIN 2-3 in univariate analysis, but these associations lost significance after taking HPV into account. Smoking was associated with CIN 2-3 (odds ratio (OR) 2.6, 95% confidence interval (CI) 1.7-4.0), the effect was dose-dependent (P = 0.002) and the smoking-associated risk was not affected by adjusting for HPV, neither when adjusting for HPV DNA (OR 2.5, CI 1.3-4.9) nor when adjusting for HPV seropositivity (OR 3.0, CI 1.9-4.7). In conclusion, after taking HPV into account, smoking appeared to be the most significant environmental risk factor for cervical neoplasia.

A novel and rapid PCR-based method for genotyping human papillomaviruses in clinical samples

Many human papillomavirus (HPV) genotypes are associated with cervical carcinoma. We demonstrate the utility of an innovative technique for genotyping of HPV in cervical tissue samples. This method provides an accurate means of identification of the specific HPV genotypes present in clinical specimens. By using the MY09-MY11 and the GP5(+)-GP6(+) consensus primer pairs, HPV sequences were amplified by nested PCR from DNA isolated from cervical smear samples. This led to the production of an approximately 140-bp PCR product from the L1 (major capsid) gene of any of the HPVs present in the sample. PCR was performed with a deoxynucleoside triphosphate mixture which resulted in the incorporation of deoxyuridine into the amplified DNA product at positions where deoxythymidine would normally be incorporated at a frequency of about once or twice per strand. Following the PCR, the product was treated with an enzyme mix that contains uracil N-glycosylase (UNG) and endonuclease IV. UNG removes the uracil base from the nucleotide, and endonuclease IV cleaves the phosphodiester bond at this newly formed abasic site, producing fragments of various sizes. By having end labeled one of the amplification primers, a DNA ladder which is analogous to a "T-sequencing ladder" was produced upon electrophoresis of the products. By comparing this T-sequencing ladder to the known sequences of HPVs, the genotypes of unknown HPV isolates in samples were assigned. Data showing the utility of this technique for the rapid analysis of clinical samples are presented.