Human papillomavirus triage of atypical squamous cells of undetermined significance: cost-effective, but at what cost?

Human papillomavirus testing versus repeat cytology for triage of minor cytological cervical lesions

BACKGROUND

Atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intra-epithelial lesions (LSIL) are minor lesions of the cervical epithelium, detectable by cytological examination of cells collected from the surface of the cervix of a woman.Usually, women with ASCUS and LSIL do not have cervical (pre-) cancer, however a substantial proportion of them do have underlying high-grade cervical intra-epithelial neoplasia (CIN, grade 2 or 3) and so are at increased risk for developing cervical cancer. Therefore, accurate triage of women with ASCUS or LSIL is required to identify those who need further management.This review evaluates two ways to triage women with ASCUS or LSIL: repeating the cytological test, and DNA testing for high-risk types of the human papillomavirus (hrHPV) - the main causal factor of cervical cancer.

OBJECTIVES

Main objective To compare the accuracy of hrHPV testing with the Hybrid Capture 2 (HC2) assay against that of repeat cytology for detection of underlying cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) or grade 3 or worse (CIN3+) in women with ASCUS or LSIL. For the HC2 assay, a positive result was defined as proposed by the manufacturer. For repeat cytology, different cut-offs were used to define positivity: Atypical squamous cells of undetermined significance or worse (ASCUS+), low-grade squamous intra-epithelial lesions or worse (LSIL+) or high-grade squamous intra-epithelial lesions or worse (HSIL+).Secondary objective To assess the accuracy of the HC2 assay to detect CIN2+ or CIN3+ in women with ASCUS or LSIL in a larger group of reports of studies that applied hrHPV testing and the reference standard (coloscopy and biopsy), irrespective whether or not repeat cytology was done.

SEARCH METHODS

We made a comprehensive literature search that included the Cochrane Register of Diagnostic Test Accuracy Studies; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (through PubMed), and EMBASE (last search 6 January 2011). Selected journals likely to contain relevant papers were handsearched from 1992 to 2010 (December). We also searched CERVIX, the bibliographic database of the Unit of Cancer Epidemiology at the Scientific Institute of Public Health (Brussels, Belgium) which contains more than 20,000 references on cervical cancer.More recent searches, up to December 2012, targeted reports on the accuracy of triage of ASCUS or LSIL with other HPV DNA assays, or HPV RNA assays and other molecular markers. These searches will be used for new Cochrane reviews as well as for updates of the current review.

SELECTION CRITERIA

Studies eligible for inclusion in the review had to include: women presenting with a cervical cytology result of ASCUS or LSIL, who had undergone both HC2 testing and repeat cytology, or HC2 testing alone, and were subsequently subjected to reference standard verification with colposcopy and colposcopy-directed biopsies for histologic verification.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data from the selected studies, and obtained additional data from report authors.Two groups of meta-analyses were performed: group I concerned triage of women with ASCUS, group II concerned women with LSIL. The bivariate model (METADAS-macro in SAS) was used to assess the absolute accuracy of the triage tests in both groups as well as the differences in accuracy between the triage tests.

MAIN RESULTS

The pooled sensitivity of HC2 was significantly higher than that of repeat cytology at cut-off ASCUS+ to detect CIN2+ in both triage of ASCUS and LSIL (relative sensitivity of 1.27 (95% CI 1.16 to 1.39; P value < 0.0001) and 1.23 (95% CI 1.06 to 1.4; P value 0.007), respectively. In ASCUS triage, the pooled specificity of the triage methods did not differ significantly from each other (relative specificity: 0.99 (95% CI 0.97 to 1.03; P value 0.98)). However, the specificity of HC2 was substantially, and significantly, lower than that of repeat cytology in the triage of LSIL (relative specificity: 0.66 (95% CI 0.58 to 0.75) P value < 0.0001).

AUTHORS' CONCLUSIONS

HPV-triage with HC2 can be recommended to triage women with ASCUS because it has higher accuracy (significantly higher sensitivity, and similar specificity) than repeat cytology. When triaging women with LSIL, an HC2 test yields a significantly higher sensitivity, but a significantly lower specificity, compared to a repeat cytology. Therefore, practice recommendations for management of women with LSIL should be balanced, taking local circumstances into account.

Screening for Cervical Cancer with the Human Papillomavirus Test in an Area of Central Italy with No Previous Active Cytological Screening Programme

Objective

We report performance indicators and costs of the first round of a cervical cancer screening programme based on the human papillomavirus (HPV)-DNA test.

Methods

We implemented a demonstration study using HPV as the primary test in Guidonia, Italy (90,000 inhabitants). All women aged 25-64 were invited to undergo a Hybrid Capture II high-risk HPV test. Two cervical samplings, smear and liquid, were taken. The smear was dyed and interpreted only for HPV-positive (HPV+) women. Women with a non-negative Pap smear were referred for colposcopy, women HPV+/cytology negative were referred to one-year follow-up with HPV. A cost-analysis indicated the price at which the HPV-based and cytological screening would cost the same per screened woman and per lesion found.

Results

Of 24,000 women invited, 7639 accepted and 427 (5.6%) were HPV+; 141 (34%) of these had a non-negative Pap test, and 20 cervical intraepithelial neoplasia (CIN) 2 or higher were found (positive predictive value 15%). Compliance to one-year follow-up was 58% (166/286); 90 (54%) were HPV-positive and five additional lesions were found (positive predictive value 9%; overall detection rate 3.4/1000). The cost analysis showed that at a price of 8.3 euros per HPV DNA test, the strategy using HPV as primary test followed by cytological triage would cost the same per screened woman, while at a price of 12.7 euros it would have the same cost per CIN2+ found.

Conclusion

The workload for management of positive women was similar to cytological screening. Low compliance to one-year follow-up was the main barrier to effectiveness. The price of HPV test should be about 9 euros to maintain the same screening budget, and can go as high as 13 euros per lesion found.

The use of p16(INK4A) immunocytochemistry in "Atypical squamous cells which cannot exclude HSIL" compared with "Atypical squamous cells of undetermined significance" in liquid-based cervical smears

Even though p16(INK4a) (p16) immunocytochemistry has proven a useful accessory tool verifying the identification of atypical squamous cells of undetermined significance (ASC-US) categorized smears, the procedure still has limitations. To date few studies examining the usefulness of p16 immunocytochemistry in atypical squamous cells which cannot exclude HSIL (ASC-H), compared with ASC-US in liquid-based cervical smears. Therefore, we examined the correlation of p16 immunocytochemical staining with follow-up biopsy results on ASC-H categorized smears and compared the data with those classified as ASC-US on 105 liquid-based cytology samples. We found no statistical significance in the p16 expression of ASC-US smears and the presence of squamous intraepithelial lesions (SIL) in follow-up biopsies (p = 0.546). However, p16 expression did significantly correlate with the presence of SIL (p = 0.002) in ASC-H smears. There was a statistically significant relationship between p16 expression and presence of high grade squamous intraepithelial lesions (HSIL) or more on the follow-up biopsies in both ASC-US (p = 0.012) and ASC-H (p < 0.001) categorized smears. In ASC-US categorized smears, there was no statistical significance between p16 expression and the HR-HPV viral load (p = 0.091). But there was a statistical significance between p16 expression and the HR-HPV viral load (p < 0.001) in ASC-H categorized smears. Our results indicate that p16 immunostaining is a much better useful marker for HR-HPV infection and detection of SIL in ASC-H categorized smears compared to those defined as ASC-US.

Linear array genotyping and hybrid capture II assay in detecting human papillomavirus genotypes in women referred for colposcopy due to abnormal Papanicolaou smear

Summary:

The main objective of this study was to assess the feasibility of human papillomavirus (HPV) genotyping in women referred for colposcopy due to abnormal Papanicolaou (Pap) smear. A series of 248 women referred for colposcopy due to an abnormal Pap smear were analysed with the Roche Linear Array HPV genotyping test detecting 37 most frequent HPV types, and compared with hybrid capture II (HCII) assay for oncogenic (high-risk [HR] HPV) types as well as for p16INK4a expression using immunocytochemistry. All tests were performed in cervical samples collected in PreservCyt® liquid media for liquid-based cytology (ThinPrep), and colposcopic biopsy and/or loop electro excision procedure cone biopsy was used as the gold standard. HPV16 was the single most frequent genotype (29/258; 11.7%), followed by HPV51 (4.4%), HPV66 (3.6%), HPV42, 52 and 56 (3.2% for all). Linear array genotyping test significantly predicts both abnormal colposcopy (odds ratio [OR] = 9.0; 3.12-25.93), high-grade squamous intraepithelial lesions (OR = 9.6; 1.26-74.17) and cervical intraepithelial neoplasia (CIN) 3+ (OR = 29.3; 3.95-218.06). In detecting CIN3, linear array was equivalent (97.6%) to colposcopy in sensitivity (SE), both being superior to HCII (92.7%). Concordance between linear array and HCII was moderate (Cohen's kappa κ = 0.547; 95% confidence interval [CI]: 0.435-659). Specificity (SP) and positive predictive value (PPV) of linear array were significantly improved, if only HPV16 genotype was considered. Performance in the best balance is obtained, when linear array and colposcopy are combined, giving 82.9% SE, 93.9% SP, 73.9% PPV and 96.3% negative predictive value (NPV) as predictor of CIN3+ (OR 74.5; 95% CI: 27.36-202.72). In conclusion, linear array for HR-HPV is a highly sensitive test (97.6%) with high NPV (98.9%) in detecting CIN3+ lesions. HPV16 genotyping alone significantly improves SP and PPV of this test in management of women with abnormal cytology.

Human papillomavirus triage of women with persistent borderline or mildly dyskaryotic smears: Comparison of costs and side effects of three alternative strategies

The conventional direct referral to colposcopy of persistent borderline or mildly dyskaryotic (BMD) smears in cervical cancer screening leads to considerable unnecessary referrals and associated anxiety and costs. This may be improved by including testing for oncogenic human papillomavirus (HPV) in the triage. We assessed costs and side effects (referrals, treatments and time in follow-up) for 3 possible HPV triage strategies (immediate HPV testing, a 6-month delay in HPV testing, a 2-stage combination of both) and compared them with the conventional strategy. The assessments are based on recent Dutch data from various national databases and trials. We estimated that the referral rate could be reduced by 49, 58 and 58% with immediate, delayed and 2-stage HPV testing, respectively. As a consequence, the average length of follow-up, as well as average costs, also decrease. Therefore, we advocate including HPV testing before referring to colposcopy. Among the 3 HPV strategies, analysis of additional aspects favors implementation of immediate HPV testing.