Detection Of Carcinogenic Human Papillomavirus Research Articles

Comparison of Human Papillomavirus Detections in Urine, Vulvar, and Cervical Samples from Women Attending a Colposcopy Clinic

While urine-based sampling for human papillomavirus (HPV) is being explored as a simple and noninvasive approach for cervical cancer screening, data comparing HPV genotyping in urine and those in cellular sampling of the cervix and vulva, and their correlation with rigorously confirmed cervical disease status, are sparse. We performed HPV genotyping on voided-urine and clinician-collected vulvar and cervical samples from 72 women undergoing colposcopy. Although urine-based HPV carcinogenic HPV detection was lower (58.3%) than cervical (73.6%) and vulvar (72.1%) detection (P = 0.05 and 0.07, respectively), the agreement of urine HPV with cervical and vulvar HPV was moderate (kappa = 0.55) and substantial (kappa = 0.62), respectively. Urine-based carcinogenic HPV detection had a clinical sensitivity of 80.8% (95% confidence interval [CI] = 60.7 to 93.5) and a specificity of 53.3% (95% CI = 37.9 to 68.3) for diagnosing cervical intraepithelial neoplasia grades 2/3 (CIN2/3) on histology; 90.0% of CIN3 was positive for urine HPV. The corresponding sensitivity and specificity values for vulvar sampling were 92% (95% CI = 74 to 99) and 40.5% (95% CI = 25.6 to 56.7), and those for cervical sampling were 96.2% (95% CI = 80.4 to 99.9) and 40% (95% CI = 25.7 to 55.7), respectively. HPV16 was the most common carcinogenic genotype detectable in 25% of urine, 33.8% of vulvar, and 31.9% of cervical samples overall, with prevalence increasing with cervical disease grade, regardless of the sampling method. Stronger cervical HPV PCR signal strengths were associated with increased frequency of urine HPV detection. In summary, the relatively lower detection rates but comparable clinical performance of urine-based HPV sampling underscore the need for larger studies to evaluate urine-based sampling for cervical cancer screening, epidemiologic studies, and postvaccination HPV disease surveillance.

Human papillomavirus genotypes detected in clinician-collected and self-collected specimens from women living in the Mississippi Delta

BackgroundThere are no data available on human papillomavirus (HPV) infections in women living in the Mississippi Delta, where cervical cancer incidence and mortality among African American women is among the highest in the United States. The aim of this analysis was to report the age-specific prevalence of HPV in this population.MethodsWe recruited 443 women, 26–65 years of age, from the general population of women living in the Mississippi Delta to participate; 252 women had been screened for cervical cancer within the last 3 years while 191 had not. Women underwent a pelvic exam and had clinician-collected Pap sample taken for the routine cervical cancer screening by cytology. Women were asked to collect a self-collected specimen at home and return it to the clinic. Both specimens were tested for HPV genotypes.ResultsFour hundred and six women (91.6%) had HPV genotyping results for the clinician-collected and self-collected specimens. The prevalence of carcinogenic HPV was 18.0% (95% CI: 14.4%-22.1%) for clinician-collected specimens and 26.8% (95% CI: 22.6%-31.4%) for self-collected specimens. The concordance for the detection of carcinogenic HPV between clinician-collected and self-collected specimens was only fair (kappa = 0.54). While the prevalence of carcinogenic HPV in either sample decreased sharply with increasing age (ptrend< 0.01), the prevalence of non-carcinogenic HPV did not, especially the prevalence of HPV genotypes in the alpha 3/4/15 phylogenetic group.ConclusionsThe prevalence of carcinogenic HPV in our sample of women living in the Mississippi Delta was greater than the prevalence reported in several other U.S. studies. The high carriage of HPV infection, along with lack of participation in cervical cancer screening by some women, may contribute to the high cervical cancer burden in the region.

Rapid genotyping of carcinogenic human papillomavirus by loop-mediated isothermal amplification using a new automated DNA test (Clinichip HPV™)

This study was designed to evaluate the Clinichip HPV test, a new DNA test that detects carcinogenic human papillomavirus (HPV) rapidly by loop-mediated isothermal amplification and performs genotyping of all 13 carcinogenic types using automated DNA chip technology with an assay time 2.5h. Using this test, 247 Japanese women (109 with normal cytology, 43 with cervical intraepithelial neoplasia grade 1, 60 with cervical intraepithelial neoplasia grade 2/3 and 35 with invasive cervical cancer) were tested for carcinogenic HPV genotypes. The results were compared to those obtained by the polymerase chain reaction-amplified DNA sequencing using 13 type-specific primers. Overall, there was very good agreement for the detection of carcinogenic HPV between the Clinichip test and direct sequencing, with 95.5% total agreement and a kappa value of 0.91. Comparison of the detection of individual HPV types shows that the overall agreement was also high (range: 96.8-100%). In women with cervical intraepithelial neoplasia grade 2 or worse, the detection rate of carcinogenic HPV was 95.7% by both the Clinichip test and the direct-sequencing method, indicating complete agreement between the two methods. In conclusion, it was found that the Clinichip test is a promising new laboratory method for genotyping of carcinogenic HPV.

Comparison of the cobas Human Papillomavirus (HPV) Test with the Hybrid Capture 2 and Linear Array HPV DNA Tests

The cobas human papillomavirus (HPV) test (cobas) was recently approved by the U.S. Food and Drug Administration (FDA) and identifies HPV16 and HPV18 separately as well as detecting a pool of 11 HR-HPV genotypes (HPV31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -68) and also HPV66. We compared cobas, Linear Array (LA), and Hybrid Capture 2 (HC2) assays for detection of carcinogenic HPV DNA, and cobas and LA for detection of HPV16 and HPV18 DNA, among the first 1,852 women enrolled in the HPV Persistence and Progression Cohort (PaP Cohort) study. Specimens were tested by all 3 assays 1 year after an HC2-positive result. In 1,824 specimens with cobas results, cobas had an 85.9% agreement with HC2 and 91.0% agreement with LA for carcinogenic HPV detection. When results between cobas and HC2 disagreed, cobas tended to call more women HPV positive (P < 0.01). Categorizing cobas and LA results hierarchically according to cancer risk (HPV16, HPV18, other carcinogenic HPV genotypes, or carcinogen negative), there was a 90% agreement for all categories of HPV (n = 1,824). We found good agreement between the two U.S. FDA-approved HPV tests, with discrepancies between the two assays due to specific characteristics of the individual assays. Additional studies are needed to compare HC2 and cobas for detecting and predicting CIN3 to understand the clinical implications of the discrepant test results between the two tests.

Evaluation of a New DNA Test for Detection of Carcinogenic Human Papillomavirus

Using archived specimens, we evaluated a new automated real-time PCR assay (BD Diagnostics) that detects all carcinogenic human papillomaviruses (HPV) and provides HPV genotyping for seven of them, including HPV16 and HPV18, the two most carcinogenic HPV genotypes. We found comparable results with Hybrid Capture 2 (HC2) for detection of carcinogenic HPV (n = 473) and with Linear Array and Line Blot Assay (n = 371) for detection of individual HPV genotypes.

Do selective estrogen receptor modulators treat cervical precancer and cancer? Time to pool data from relevant trials

Based on the nearly absolute etiologic link between carcinogenic human papillomavirus (HPV) and cervical cancer, two new approaches for the prevention of cervical cancer have emerged: (1) HPV vaccination for primary HPV prevention in younger women and (2) carcinogenic HPV detection for secondary prevention via identifying and treating cervical precancer and early cancers. Both have demonstrated high degrees of efficacy with maximum effectiveness guided by an understanding of the causal model and application of these technologies in an age appropriate manner.1 Despite the advent of these promising prevention tools, there is a real need to develop nonsurgical methods for treating cervical precancerous lesions and even early cancer for three reasons. First, current HPV vaccines are prophylactic and do not treat pre-existing HPV infections.1 Second, surgical excision of screen-detected precancerous lesions, while a highly efficacious (90–95%) treatment1 increases the risk of preterm delivery and infant morbidity and mortality.2 Third, most women who screen positive by a Pap and/or HPV do not have clinically actionable disease, yet these women are at risk of cervical precancer and cancer in the future and must be followed up intensively. In addition, in the low-resource settings, surgical methods are not commonly available and cryotherapy, while moderately efficacious when its use is limited to smaller lesions, causes significant watery discharge and requires sexual abstinence for several weeks to permit healing of treated epithelium. Despite the knowledge that HPV infection is the obligate cause of cervical cancer, targeted immunological approaches for therapy such as therapeutic vaccines have been unsuccessful.3 Chung and Lambert4 present a novel approach of using estrogen receptor antagonists (selective estrogen receptor modulators or SERMs) to treat cervical precancer and cancer. As noted by the authors, there are strongly supportive laboratory5 and epidemiological data6, 7 that estrogen plays contributing role in cervical carcinogenesis. In this study, Chung and Lambert4 successfully treated 7 E6/E7 transgenic mice that spontaneously manifested cervical cancer with Raloxifene, an estrogen receptor antagonist that reduces the risk of breast cancer. To investigate whether Raloxifene might reduce the incidence of cervical cancer and its immediate precursor, carcinoma in situ (CIS), previously unpublished data on these outcomes from two randomized clinical trials to evaluate two SERMs, tamoxifen and raloxifene, for breast cancer risk reduction were analyzed. The NSABP (National Surgical Adjuvant Breast and Bowel Project), an NCI funded Cooperative Group, has designed and conducted the two large breast cancer prevention trials, Breast Cancer Prevention Trial P-1 (BCPT-P1)8 and Study of Tamoxifen vs. Raloxifene (STAR).9 While both tamoxifen and raloxifene are estrogen receptor antagonists in breast tissue, raloxifene is an estrogen receptor antagonist whereas tamoxifen is an agonist in the human reproductive tract (e.g., Tamoxifen increases the risk of endometrial cancer while raloxifene does not.).4, 10, 11 However, as shown in the Table 1, despite small numbers, there was no evidence that long-term raloxifene use reduces, or long-term tamoxifen use increases, the risk of cervical CIS and cancer (n.b., results were combined because SERMS were reported to treat both in the mouse models, and CIS has a high risk of invading if left untreated12) (BCPT P-1: Placebo vs. Tamoxifen, p = 1.0, two-sided Fisher's exact; STAR: Tamoxifen vs. Raloxifene, p = 1.0, two-sided Fisher's exact). This post-hoc analysis was limited by small numbers. Data from other clinical trials of SERMs13, 14 should be pooled to examine the impact of SERMs on outcomes of cervical precancer and cancer. Until evidence is forthcoming on the positive effects of SERMs on cervical precancer and cancer in humans, extreme caution in interpreting data from mouse models is warranted. Despite the probable role of estrogens in cervical carcinogenesis, the protective effects of SERMs against cervical cancer cannot be inferred based on mouse models. Importantly, the therapeutic effectiveness of SERMs would need to be exceeding high to be acceptable, given the efficacy of current methods of treatment for cervical intraepithelial neoplasia15 and early cervical cancer.16 Dr. Castle acknowledges Dr. Joseph Costantino (University of Pittsburgh, Pittsburgh, PA, USA) for providing data from Breast Cancer Prevention Trial P-1 (BCPT-P1) and the Study of Tamoxifen vs. Raloxifene (STAR). Dr. Castle was supported by the Intramural Research Program of the NIH, National Cancer Institute and he reports no conflicts of interest. Yours sincerely, Philip E. Castle

Cervical cancer prevention

Cervical cancer is the second most common female tumor worldwide, and its incidence is disproportionately high (>80%) in the developing world. In the United States, in which Papanicolaou (Pap) tests have reduced the annual incidence to approximately 11,000 cervical cancers, >60% of cases are reported to occur in medically underserved populations as part of a complex of diseases linked to poverty, race/ethnicity, and/or health disparities. Because carcinogenic human papillomavirus (HPV) infections cause virtually all cervical cancer, 2 new approaches for cervical cancer prevention have emerged: 1) HPV vaccination to prevent infections in younger women (aged < or =18 years) and 2) carcinogenic HPV detection in older women (aged > or =30 years). Together, HPV vaccination and testing, if used in an age-appropriate manner, have the potential to transform cervical cancer prevention, particularly among underserved populations. Nevertheless, significant barriers of access, acceptability, and adoption to any cervical cancer prevention strategy remain. Without understanding and addressing these obstacles, these promising new tools for cervical cancer prevention may be futile. In the current study, the delivery of cervical cancer prevention strategies to these US populations that experience a high cervical cancer burden (African-American women in South Carolina, Alabama, and Mississippi; Haitian immigrant women in Miami; Hispanic women in the US-Mexico Border; Sioux/Native American women in the Northern Plains; white women in the Appalachia; and Vietnamese-American women in Pennsylvania and New Jersey) is reviewed. The goal was to inform future research and outreach efforts to reduce the burden of cervical cancer in underserved populations.

Comparison of Two PCR-Based Human Papillomavirus Genotyping Methods

We compared two consensus primer PCR human papillomavirus (HPV) genotyping methods for the detection of individual HPV genotypes and carcinogenic HPV genotypes as a group, using a stratified sample of enrollment cervical specimens from sexually active women participating in the NCI/Costa Rica HPV16/18 Vaccine Efficacy Trial. For the SPF(10) method, DNA was extracted from 0.1% of the cervical specimen by using a MagNA Pure LC instrument, a 65-bp region of the HPV L1 gene was targeted for PCR amplification by using SPF(10) primers, and 25 genotypes were detected by reverse-line blot hybridization of the amplicons. For the Linear Array (LA) method, DNA was extracted from 0.5% of the cervical specimen by using an MDx robot, a 450-bp region of the HPV L1 gene was targeted for PCR amplification by using PGMY09/11 L1 primers, and 37 genotypes were detected by reverse-line blot hybridization of the amplicons. Specimens (n = 1,427) for testing by the LA method were randomly selected from strata defined on the basis of enrollment test results from the SPF(10) method, cytology, and Hybrid Capture 2. LA results were extrapolated to the trial cohort (n = 5,659). The LA and SPF(10) methods detected 21 genotypes in common; HPV16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, -68, and -73 were considered the carcinogenic HPV genotypes. There was no difference in the overall results for grouped detection of carcinogenic HPV by the SPF(10) and LA methods (35.3% versus 35.9%, respectively; P = 0.5), with a 91.8% overall agreement and a kappa value of 0.82. In comparisons of individual HPV genotypes, the LA method detected significantly more HPV16, HPV18, HPV39, HPV58, HPV59, HPV66, and HPV68/73 and less HPV31 and HPV52 than the SPF(10) method; inclusion of genotype-specific testing for HPV16 and HPV18 for those specimens testing positive for HPV by the SPF(10) method but for which no individual HPV genotype was detected abrogated any differences between the LA and SPF(10) methods. The LA method detected more carcinogenic-HPV-genotype infections per specimen than the SPF(10) method (P < 0.001). In conclusion, the LA method and the SPF(10) method with HPV16 and HPV18 genotype-specific detection among ungenotyped HPV-positive specimens were comparable for detection of HPV16 and HPV18, the two HPV genotypes targeted by current prophylactic HPV vaccines. Both approaches are suitable for monitoring the impact of HPV16/18 vaccines in clinical trials.

A Comparison of Linear Array and Hybrid Capture 2 for Detection of Carcinogenic Human Papillomavirus and Cervical Precancer in ASCUS-LSIL Triage Study

We were interested in comparing the performance of Linear Array (LA; Roche Molecular Systems) to Hybrid Capture 2 (hc2; Digene) for the detection of carcinogenic human papillomavirus (HPV) and cervical precancer. LA and hc2 results were compared on baseline specimens collected from women with an atypical squamous cells of undetermined significance (ASCUS) Pap referred into ASCUS and Low-Grade Squamous Intraepithelial Lesion Triage Study (n = 3,488). hc2 was conducted at the time of the study on liquid cytology specimens. LA was conducted retrospectively on aliquots from a second, stored cervical specimen masked to the hc2 results and clinical data. Paired LA and hc2 results (n = 3,289; 94%) were compared for the detection of carcinogenic HPV (HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) and 2-year cumulative cervical intraepithelial neoplasia (CIN) grade >or=3 as diagnosed by the quality-control pathology review. LA was more likely to test positive for carcinogenic HPV than hc2 (55% versus 53%; P = 0.001). For 2-year cumulative >or=CIN3, LA and hc2 had similar sensitivities (93.3% versus 92.6%, respectively; P = 1), and LA was marginally less specific than hc2 (48.1% versus 50.6%, respectively; P = 0.05). LA and hc2 had similar negative predictive values (98.70% versus 98.64% respectively; P = 0.4), and LA had a slightly lower positive predictive value than hc2 (14.6% versus 15.1%, respectively; P < 0.0001). We observed that LA and hc2 performed similarly in the detection of carcinogenic HPV and identification of CIN3 among women with an ASCUS Pap.

Detection of Human Papillomavirus Genotypes Among High-Risk Women: A Comparison of Hybrid Capture and Linear Array Tests

To assess the concordance and performance of 2 different assays in detection of human papillomavirus (HPV) genotypes among women with abnormal Pap smear. A series of 575 women referred for colposcopy due to an abnormal Pap smear were analyzed with the Linear Array HPV Genotyping test detecting 37 HPV types and compared with Hybrid Capture II (HCII) assay for detection of carcinogenic HPV. Histologic outcomes of cervical intraepithelial neoplasia grade 2 (CIN2) or worse (CIN2+) and CIN3+ were the primary endpoints. Clinical performance, including receiver operating characteristics, was determined for both tests. HCII and linear array (LA) were concordant in 88.1% (433/491; 95% CI 85.3%-91.0%), having a substantial agreement with regular kappa (kappa = 0.70, 95% CI 0.62-0.77) and almost perfect agreement with weighted kappa (ICC = 0.82, 95% CI 0.7-0.85). In detecting CIN2+ and CIN3+, LA is 5% and 6% more sensitive but 9.5% and 8.7% less specific than HCII (area under ROC curve; P = 0.317 and P = 0.875, respectively). Performance of HCII and LA does not significantly differ in detecting CIN2+ or CIN3+.

Comparison of Linear Array and Line Blot Assay for Detection of Human Papillomavirus and Diagnosis of Cervical Precancer and Cancer in the Atypical Squamous Cell of Undetermined Significance and Low-Grade Squamous Intraepithelial Lesion Triage Study

We evaluated Linear Array (LA), a newly commercialized PGMY09/11 L1 consensus primer PCR test that detects 37 human papillomavirus (HPV) genotypes by reverse line blot hybridization, for the detection of individual HPV genotypes and carcinogenic HPV and its clinical performance for detecting 2-year cumulative cervical precancer and cancer using archived specimens from the Atypical Squamous Cell of Undetermined Significance (ASCUS) and Low-Grade Squamous Intraepithelial Lesion Triage Study. LA testing was conducted on enrollment specimens from women referred because of an ASCUS Pap test. To gauge the performance of the new test, the results were compared to those of its prototype predecessor assay, Line Blot Assay (LBA), restricted to paired results (n = 3,335). LA testing was done masked to LBA results and clinical outcomes. The results of LA and LBA testing were compared for detection of carcinogenic HPV and clinical outcomes of cervical precancer and cancer. Overall, 50% and 55% of the women tested positive for carcinogenic HPV by LBA and LA, respectively (P < 0.0001). The percent agreement for carcinogenic HPV detection was 88%, percent positive agreement was 80%, and kappa was 0.76 for detection of carcinogenic HPV by the two assays. There was a significant increase in detection by LA for most of the 37 HPV genotypes targeted by both assays, including for 13 of 14 carcinogenic HPV genotypes. LA detected more multiple-genotype infections for all HPV genotypes among HPV-positive women (P < 0.0001) and for carcinogenic HPV genotypes among carcinogenic-HPV-positive women (P < 0.0001). LA was more sensitive (92.3% versus 87.1%; P = 0.003) and less specific (48.2% versus 54.0%; P < 0.0001) than LBA for 2-year cumulative cervical precancer and cancer as diagnosed by the Pathology Quality Control Group. In conclusion, we found LA to be a promising assay for the detection of HPV genotypes and carcinogenic HPV, and it may be clinically useful for the detection of cervical precancer and cancer in women with equivocal cytology.

Comparability of Self-Collected Vaginal Swabs and Physician-Collected Cervical Swabs for Detection of Human Papillomavirus Infections in Rakai, Uganda

The objective of this study was to compare human papillomavirus (HPV) DNA testing between self-administered vaginal swabs and physician-administered cervical swabs in women from rural Rakai District, Uganda. Between 2002 and 2003, women from a population-based cohort participated in an HPV study. Women collected self-administered vaginal swabs and were also offered a pelvic examination, which included physician-collected cervical samples. Hybrid-capture 2 was used to determine carcinogenic HPV status. Polymerase chain reaction was used to determine HPV genotypes. Unweighted kappa statistics were used to determine agreement. Compliance with self-collected swabs was > or =86%; however, only 51% accepted a pelvic examination. Carcinogenic HPV prevalence was 19% in self-collected and 19% in physician-collected samples. Agreement among paired observations was 92% with a kappa of 0.75. Kappa between self- and physician-collected samples was similar in HIV strata (k = 0.71 and 0.75 for HIV-positive and HIV-negative, respectively). In this community-based setting, detection of carcinogenic HPV was comparable among self- and physician-administered samples. Self-collection is a feasible and accurate means of obtaining HPV samples from women in resource-poor settings or persons reluctant to undergo a pelvic examination.

A Cross-sectional Study of a Prototype Carcinogenic Human Papillomavirus E6/E7 Messenger RNA Assay for Detection of Cervical Precancer and Cancer

To evaluate carcinogenic human papillomavirus (HPV) mRNA for E6 and E7 mRNA detection on clinical specimens to identify women with cervical precancer and cancer. We evaluated a prototype assay that collectively detects oncogenes E6/E7 mRNA for 14 carcinogenic HPV genotypes on a sample of liquid cytology specimens (n=531), masked to clinical data and to the presence of HPV genotypes detected by PGMY09/11 L1 consensus primer PCR assay. We found an increasing likelihood of testing positive for carcinogenic HPV E6/E7 mRNA with increasing severity of cytology (P(Trend) < 0.0001) and histology (P(Trend) < 0.0001), with 94% of cervical intraepithelial neoplasia grade 3 (CIN3) histology cases (46 of 49) and all five cancer cases testing positive for carcinogenic HPV E6/E7 mRNA. Overall, fewer specimens tested positive for carcinogenic HPV E6/E7 mRNA than for carcinogenic HPV DNA (P<0.0001, McNemar's chi(2) test), especially in women with <CIN1 (P<0.0001). We also found that using a higher positive cutpoint for detection of carcinogenic HPV E6/E7 mRNA improved the association of positive test results with cervical precancer and cancer by reducing the number of test positives in women without precancer without reducing clinical sensitivity for cervical precancer and cancer compared with detection of carcinogenic HPV E6/E7 mRNA using a lower positive cutpoint by the same assay and with detection of carcinogenic HPV DNA. We found that carcinogenic HPV E6/E7 mRNA is a potentially useful biomarker for detection of cervical precancer and cancer and warrants further evaluation.

Mouthwash as a Low-Cost and Safe Specimen Transport Medium for Human Papillomavirus DNA Testing of Cervicovaginal Specimens

The usefulness of mouthwash as a transport medium for cervical specimens for carcinogenic human papillomavirus (HPV) DNA testing has not been evaluated. Two cervical specimens were collected from each of 34 patients, with one placed in mouthwash (Scope, Proctor and Gamble, Inc.) and the other in a liquid cytology medium commonly used for HPV DNA testing in alternating order. Paired specimens were tested by a PCR assay for carcinogenic HPV and a PCR HPV genotyping assay for 37 HPV types at 0, 3, and 6 weeks after collection; the results of the HPV genotyping assay were categorized into HPV risk groups according to cancer risk (HPV-16 > HPV-18 > other carcinogenic HPV types > noncarcinogenic HPV types > negative). After 4 months of storage, specimens were tested using a second, non-PCR test for carcinogenic HPV. We observed a >or=94% total agreement and kappa values of >or=0.88 between media at each time point for PCR-detected carcinogenic HPV. We observed a >or=74% total agreement, >or=0.62 unweighted kappa, and >or=0.75 linearly weighted kappa between media at each time point for PCR-detected HPV cancer risk category. Finally, we observed an 88% total agreement and kappa of 0.77 between media for carcinogenic HPV detection using a second test after 4 months of storage. We suggest that mouthwash might be used as a low-cost, safe, nonflammable storage and transport medium for cervical specimens for HPV DNA testing in cervical cancer screening programs.

Comparison of the SPF 10 -LiPA System to the Hybrid Capture 2 Assay for Detection of Carcinogenic Human Papillomavirus Genotypes among 5,683 Young Women in Guanacaste, Costa Rica

The objective of this analysis was to compare the performance characteristics of two human papillomavirus (HPV) DNA detections assays, the Hybrid Capture 2 assay (HC2) and the SPF(10) assay, for the detection of carcinogenic HPV. Data are from the enrollment visits of women who participated in the randomized, double-blind, placebo-controlled phase III HPV16/18 Vaccine Trial in Guanacaste, Costa Rica. We compared the results of HC2 and SPF(10) testing of cervical specimens. Since the line probe assay (LiPA) detection system does not distinguish between HPV type 68 (HPV68; which is targeted by HC2) and HPV73 (which is not targeted by HC2), for SPF(10)-LiPA, we defined the carcinogenic HPV types as the 12 HC2-targeted types (types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59), HPV68/73, and the HC2-cross-reactive, carcinogenic type HPV66. The kappa values and the performance characteristics for the detection of cervical abnormalities were ascertained. Paired observations were available for 5,683 sexually active, young women (median age, 21 years). The prevalence of carcinogenic HPV types was 35% (n=1,962) by HC2 and 35% (n=2,003) by SPF(10)-LiPA. There were no differences in the prevalence of carcinogenic HPV types by HC2 and SPF(10)-LiPA among women with normal, atypical squamous cells of undetermined significance and high-grade squamous intraepithelial lesion cytology. Among women with low-grade squamous intraepithelial lesion cytology, HC2 was more likely to test positive than SPF(10)-LiPA for the carcinogenic HPV types (87% and 79%, respectively; P=0.001) as a result of HC2 cross-reactivity with HPV types 40, 43, 44, 53, 54, 60, 70, and 74. The crude agreement between the two assays was 88%, with a kappa value of 0.75 (95% confidence limits, 0.73 to 0.76). We observed very good agreement between HC2 and SPF(10)-LiPA for carcinogenic HPV type detection.

Detection of Carcinogenic Human Papillomavirus in Specimens Collected with a Novel Self-Sampling Device

We compared the detection of carcinogenic human papillomavirus DNA in cervicovaginal specimens self-collected using a novel device to the detection in physician-collected cervical specimens from 137 women. The kappa value was 0.66 (95% confidence interval, 0.53 to 0.78), with an 83% overall test agreement and a 68% positive test agreement.

Human Papillomavirus Testing Following Loop Electrosurgical Excision Procedure Identifies Women at Risk for Posttreatment Cervical Intraepithelial Neoplasia Grade 2 or 3 Disease

Loop electrosurgical excision procedure (LEEP) is the predominant treatment for cervical intraepithelial neoplasia grade 2 or 3 (CIN2+) in the United States, yet following treatment approximately 10% of women are diagnosed again with CIN2+, necessitating close follow-up of such patients. Surveillance strategies using cytology and/or human papillomavirus (HPV) testing were compared among women who underwent LEEP (n = 610) in the Atypical Squamous Cells of Undetermined Significance (ASCUS) Low-Grade Squamous Intraepithelial Lesion (LSIL) Triage Study. Cervical specimens, collected at 6-month visits for 2 years, were used for cytology, Hybrid Capture 2 (HC2) detection of carcinogenic HPVs, and PCR for genotyping of carcinogenic and noncarcinogenic HPV types. At exit, women had colposcopy for safety and disease ascertainment. At the visit post-LEEP (median time: 4.5 months after LEEP), 36.9% [95% confidence interval (95% CI), 32.7-41.1%] of women were positive for carcinogenic HPV by PCR and 33.7% (95% CI, 29.7-37.9) had ASCUS or more severe (ASCUS+) cytology. The overall 2-year cumulative incidence of histologically confirmed posttreatment CIN2+ was 7.0%; this could be further stratified by the HPV risk category detected at the 6-month visit after LEEP. The 2-year risk associated with HPV16 positivity was 37.0%, significantly higher than for other carcinogenic HPV types (10.8%, P < 0.001), noncarcinogenic types (1.5%, P < 0.001), or testing HPV negative (0%). Post-LEEP cytology (using a positive threshold of ASCUS+) was 78.1% (95% CI, 60.0-90.7%) sensitive for detection of posttreatment CIN2+. By comparison, PCR for carcinogenic HPV and combination testing (using a positive result from carcinogenic HPV testing or cytology as the test threshold with HPV-negative ASCUS not referred) were significantly more sensitive (96.9% for each, P = 0.03); HC2 alone was nonsignificantly more sensitive (90.6%, P = 0.3). Specificity was similar for ASCUS+ cytology (69.1%, 95% CI, 64.6-73.3%) and PCR for carcinogenic HPV (67.1%, P = 0.5), yet was lower for HC2 (63.8%, P = 0.048) and combination testing (62.9%, P = 0.02). Women who tested positive after LEEP for carcinogenic HPV types, especially HPV16, had high risk of subsequent CIN2+. HPV-based detection methods, alone or in combination with cytology, may be useful to incorporate in post-LEEP management strategies.

With or Without a Gold Standard

To explore causal relationships between exposure and outcome, epidemiologists must rely on accurate measurements of both. Misclassification of either exposure or outcome will obscure causality, ie, by an inability to distinguish exposed from unexposed or “diseased” from “nondiseased.” Whenever new and purportedly better (but nonvalidated) measurements of exposure or outcome become available, epidemiologists are faced with a fundamental question of “Which test is better?” Tools for answering this question differ depending on whether a true gold standard is available. In this issue of EPIDEMIOLOGY, articles by Pepe 1 and Hagdu 2 address some of the issues surrounding comparisons of diagnostic tests with 1 and without 2 a gold standard. The receiver-operator characteristics curve (ROC) is a popular summary measure of the discriminatory ability of a clinical marker that can be used when there is a gold standard. The ROC plots sensitivity against 1-specificity (true versus false positivity) for all thresholds that could have been used to define “test positive.” An ROC curve is assessed by measuring the area under the curve (AUC), which ranges from 0.5 (no discriminatory ability) to 1.0 (perfect discriminatory ability). Two diagnostic tests can be compared by calculating the difference between the areas under their 2 ROC curves. Pepe 1 offers an alternative (nonparametric) presentation of ROC analysis that may make such analysis more accessible to epidemiologic researchers. Pepe relates the ROC curve to standardized values of the clinical marker, termed “placement values.” The placement value for an affected individual with maker value Y is the proportion of unaffected subjects (the reference population) with values higher than Y. To extend this idea to the whole population, the mean placement value or average of the percentiles is computed by averaging the placement values of the affected subjects, with the mean placement value reflecting the distribution of values in the control population. A low mean placement value indicates that the clinical marker distinguishes patients with an outcome from those without an outcome in that population. Using the fact that the ROC curve is the probability distribution of the placement values, Pepe demonstrates that the mean placement value is equal to 1-AUC. A nice feature of using placement values is that they are amenable to regression analysis to identify and control for factors that modify the performance of the clinical measurement. Both of these related approaches use all thresholds for the definition of “test positive.” In practice, users often confine their attention to regions of the ROC curve that correspond to the most clinically relevant values of test sensitivity or specificity. For example, a test that performs well for low specificity but poorly for high specificity may not be desirable. In this case, the partial area under the curve is a more appropriate measure of test performance than the AUC.