Cost-effectiveness of alternative triage strategies for atypical squamous cells of undetermined significance

Testing for human papillomavirus: data driven implications for cervical neoplasia management

The results of the National Cancer Institute-sponsored ASCUS-LSIL Triage Study (ALTS), the only randomized longitudinal trial in cytopathology, have provided a wealth of data to benchmark practice and stimulate discussion regarding the usefulness of human papillomavirus testing. These landmarks aided the American Society of Colposcopy and Cervical Pathology's broad-based consensus conference in integrating the Bethesda deliberations and ALTS data into clinical management. The outcomes of these open- and wide-ranging discussions have a direct impact on all who practice in this area. This article highlights the impact of these data on the contemporary practice of cytopathology and emphasizes the interaction between pathologists and clinicians.

Findings to date from the ASCUS-LSIL Triage Study (ALTS)

Controversy exists in the United States regarding the proper evaluation and management of low-grade squamous intraepithelial lesion (LSIL) and equivocal (atypical squamous cells of undetermined significance [ASCUS, now ASC-US]) cervical cytologic interpretations. To address this issue, the National Cancer Institute initiated the ASCUS-LSIL Triage Study (ALTS). ALTS is a multicenter, randomized clinical trial designed to evaluate 3 alternative methods of management, namely, immediate colposcopy, cytologic follow-up, and triage by human papillomavirus (HPV) DNA testing. This article summarizes the major findings of ALTS that have been published to date. Patients with ASCUS (n = 3488) or LSIL (n = 1572) were randomly assigned to research arms between November 1996 and December 1998, and were monitored for 2 years. The disease outcome was histologic cervical intraepithelial neoplasia (CIN) 3/cancer. The prevalence of oncogenic HPV was too high to permit effective triage of LSIL using HPV DNA testing by Hybrid Capture 2. However, for the women referred with a cytologic interpretation of ASCUS, HPV triage proved useful, with sensitivity equivalent to immediate colposcopy and a halving of colposcopic referrals. Among older women with ASCUS, HPV testing remained sensitive for detecting CIN 3 and cancer, but the referral percentage was dramatically lower compared to younger women. ALTS yielded insight into the performance of cytology and histopathology; experienced pathologists differed significantly in their interpretations of cervical abnormalities, especially histologic CIN 1 and cytologic ASCUS. Nonetheless, it was possible to distinguish a relatively uncommon type of ASCUS, equivocal for high-grade squamous intraepithelial lesion, that has a high positive predictive value for identifying women with underlying high-grade CIN. Many additional analyses are underway.

Laboratory implementation of human papillomavirus testing

Human papillomavirus testing is becoming an integral component of cervical cancer screening. Market forces will require most laboratories that perform Papanicolaou tests to develop a system for handling human papillomavirus testing also. Data and information are presented that may facilitate laboratories when addressing the following issues in the process of developing a human papillomavirus testing service: Which methodology is the best fit for the laboratory? Is it better to develop an in-house testing service or to send it out? How do I get started? What are the financial and economic issues, and how should they be managed?

Clinical and economic benefit of HPV-load testing in follow-up and management of women postcone biopsy for CIN2-3

This study aimed to evaluate the clinical and economic implications of integrating human papilloma virus (HPV) load testing into the follow-up and management protocol of women postconisation for high-grade cervical intraepithelial neoplasia (CIN2-3). We evaluated 130 suitable women: 63 were screened biannually by Pap smears ('conventional approach') and 67 also had HPV-load testing ('HPV approach'). More stringent criteria for undergoing colposcopy or reconisation were observed by the former group compared to the latter. Both approaches were analysed for cost effectiveness. There were 33 out of 67 (49.2%) colposcopic referrals and 24 out of 67 (35.8%) reconisation/hysterectomies with the 'conventional approach' compared to 9 out of 63 (14.2%) and 7 out of 63 (11.1%) with the 'HPV approach'. Cervical intraepithelial neoplasia 2-3 residual disease was detected in 7 out of 67 (10.5%) and 7 out of 63 (11.1%) women. The 'conventional approach' had more negative colposcopic biopsies and more negative reconisation/hysterectomy histologies than the 'HPV approach'. The respective cost per detection of one case of residual disease was US$3573 and US$3485. The 'HPV approach' required fewer colposcopic and reconisation procedures to detect one case of residual CIN2-3. Its higher positive predictive value than that of cytology provided a significant decrease in false positive rates and a reduction of US$88 per detected case.

Cervical cytological screening and human papillomavirus DNA testing in Flanders

The causal relationship between genital human papillomavirus (HPV) infection and cervical dysplasia/carcinoma has been recognised for some time. The aim of this study was to document the occurrence and distribution of HPV infection in the five provinces of the Flemish region in Belgium and to correlate the HPV DNA test results with the cytological results on simultaneously performed thin layer preparations of cervical cells. Out of a total screened group of 105107 samples, 1978 samples with cytological abnormalities were tested for HPV DNA using the MY09/MY11 consensus PCR. The mean age of the whole group was 36.9 years. The LSIL group, with a mean age of 33.6 years, was significantly younger than the other groups. There was no significant difference in HPV prevalence among the provinces. In four out of five provinces the HPV prevalence reached 100% in high-grade lesions. There is a significant increase in predominance of high-risk HPV types, with increasing abnormal cytology (17.9% WNL < 51.1% ASCUS < 83.8% LSIL < 97.2% HSIL). Three peaks of HPV DNA positivity were observed, a first at 22 yrs (82%), a second at 47 yrs (60%) and a third in women older than 65 yrs (52%). These results shed more light on HPV prevalence in Flanders and show that the MY09/MY11 consensus primer based detection system is very suitable for the detection of HPV infections in Flanders.

Results of a randomized trial on the management of cytology interpretations of atypical squamous cells of undetermined significance

OBJECTIVE

This study was undertaken to compare alternative strategies for the initial management of a cytologic diagnosis of atypical squamous cells of undetermined significance (ASCUS).

STUDY DESIGN

A total of 3488 women with a community-based ASCUS interpretation were randomly assigned to immediate colposcopy, triage that was based on enrollment HPV DNA testing and liquid-based cytology at a colposcopy referral threshold of high-grade squamous intraepithelial lesion (HSIL), or conservative management based on repeat cytology at a referral threshold of HSIL. All arms included 2 years of semiannual follow-up and colposcopy at exit. Loop electrosurgical excision procedure was offered to women with histologic diagnoses of cervical intraepithelial neoplasia (CIN) grade 2 or 3 at any visit or persistent CIN grade 1 at exit. The study end point was 2-year cumulative diagnosis of CIN grade 3.

RESULTS

The 2-year cumulative diagnosis of CIN grade 3 was 8% to 9% in all study arms. The immediate colposcopy strategy yielded 53.6% sensitivity for cumulative cases of CIN grade 3 diagnosed over 2 years. The human papillomavirus (HPV) triage strategy referred 55.6% of women and detected 72.3% of cumulative cases of CIN grade 3. A conservative management strategy of repeat cytology at the HSIL threshold referred 12.3% of women while detecting 54.6% of cumulative CIN grade 3. To compare triage tests, we re-estimated the performance of HPV and cytology in successfully referring women with underlying CIN grade 3 (ie, ignoring the insensitivity we discovered in colposcopically directed biopsies). A single enrollment HPV test identified 92.4% of the women diagnosed with CIN grade 3. Serial cytology, even at an ASCUS threshold, would have required two visits to achieve similar sensitivity (95.4%) and would have referred 67.1% to colposcopy.

CONCLUSION

HPV triage is at least as sensitive as immediate colposcopy for detecting CIN grade 3 and refers about half as many women to colposcopy. Follow-up that used repeat cytology is sensitive at an ASCUS referral threshold but requires two follow-up visits and ultimately more colposcopic examinations than HPV triage.

Thin-layer liquid-based cervical cytology and PCR for detecting and typing human papillomavirus DNA in Flemish women

The objective of this study was to document the occurrence and to correlate the prevalence of different human papillomavirus (HPV) types with the cytological results on simultaneously performed thin-layer preparations in a large population of Flemish women. During 1 year, 69 290 thin-layer preparations were interpreted using the Bethesda classification system. Using an algorithm for HPV testing based on consensus primers and type-specific PCRs in combination with liquid-based cytology, we determined the occurrence and distribution of 14 different oncogenic HPV types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68). Reflex HPV testing was performed on cytologically abnormal samples and on an age matched randomly selected control group with normal cervical cytology (n=1351). Correlation between cytology, age and prevalence for the 14 different high-risk HPV types is given. There is a significant increase in predominance of high-risk HPV types, with increasing abnormal cytology. Coinfection with multiple HPV types also increased with cytological abnormalities, and was highest in HSIL (16.7%). In Flanders, HSIL was most often associated with HPV types 16, 33, 35, 31, 18 and 51. Using thin-layer liquid-based cytology and PCR to detect HPV, it is feasible to screen large numbers of women.

Attitudes towards HPV testing: a qualitative study of beliefs among Indian, Pakistani, African-Caribbean and white British women in the UK

This study examined attitudes to human papillomavirus (HPV) testing among a purposively selected sample of women from four ethnic groups: white British, African Caribbean, Pakistani and Indian. The design was qualitative, using focus group discussion to elicit women's attitudes towards HPV testing in the context of cervical cancer prevention. The findings indicate that although some women welcomed the possible introduction of HPV testing, they were not fully aware of the sexually transmitted nature of cervical cancer and expressed anxiety, confusion and stigma about HPV as a sexually transmitted infection. The term 'wart virus', often used by medical professionals to describe high-risk HPV to women, appeared to exacerbate stigma and confusion. Testing positive for HPV raised concerns about women's sexual relationships in terms of trust, fidelity, blame and protection, particularly for women in long-term monogamous relationships. Participation in HPV testing also had the potential to communicate messages of distrust, infidelity and promiscuity to women's partners, family and community. Concern about the current lack of available information about HPV was clearly expressed and public education about HPV was seen as necessary for the whole community, not only women. The management of HPV within cervical screening raises important questions about informed participation. Our findings suggest that HPV testing has the potential to cause psychosocial harm to women and their partners and families.

Human papillomavirus and cervical cancer

Of the many types of human papillomavirus (HPV), more than 30 infect the genital tract. The association between certain oncogenic (high-risk) strains of HPV and cervical cancer is well established. Although HPV is essential to the transformation of cervical epithelial cells, it is not sufficient, and a variety of cofactors and molecular events influence whether cervical cancer will develop. Early detection and treatment of precancerous lesions can prevent progression to cervical cancer. Identification of precancerous lesions has been primarily by cytologic screening of cervical cells. Cellular abnormalities, however, may be missed or may not be sufficiently distinct, and a portion of patients with borderline or mildly dyskaryotic cytomorphology will have higher-grade disease identified by subsequent colposcopy and biopsy. Sensitive and specific molecular techniques that detect HPV DNA and distinguish high-risk HPV types from low-risk HPV types have been introduced as an adjunct to cytology. Earlier detection of high-risk HPV types may improve triage, treatment, and follow-up in infected patients. Currently, the clearest role for HPV DNA testing is to improve diagnostic accuracy and limit unnecessary colposcopy in patients with borderline or mildly abnormal cytologic test results.

Molecular detection and genotyping of pathogens: more accurate and rapid answers

Rapid molecular methods have enhanced the capabilities of laboratories to identify and characterize microbial pathogens in greater detail. Nucleic acid amplification strategies and advances in amplicon detection have been key aspects in the progress of molecular microbiology. Sophisticated new amplification-detection combinations are resulting in many applications in laboratory testing for infectious diseases. These applications include qualitative detection, sub-species-level DNA fingerprinting, molecular resistance testing and genotyping, and quantitative (viral load) testing. When applied selectively in the laboratory, these applications can enhance diagnostic approaches and clinical management and will probably evolve into standard laboratory and point-of-care testing protocols.

Health economics and cervical cancer prevention: a global perspective

Recent scientific advances are providing an opportunity to revisit strategies for cervical cancer prevention. How to invest health resources wisely, such that clinical benefits are maximized-and opportunity costs are minimized-is a critical question in the setting of new technology. In addition to an intervention's effectiveness, public health decision-making requires consideration of its feasibility, sustainability and affordability. No clinical trial or single cohort study will be able to simultaneously consider all of these components. A mathematical simulation model can be a useful tool with which to evaluate alternative cervical cancer control strategies by extending the knowledge from empirical studies to real-world situations. Models combine information about the natural history of disease with other relevant demographic, epidemiological, and economic characteristics. We describe a comprehensive Cervical Cancer Policy Model with a flexible structure that may be modified as new data on the biology of disease become available. This model provides an analytic framework to synthesize data on costs and benefits, to help design clinical guidelines, and to inform development of sound health policy. Examples of cost-effectiveness analyses conducted in the US and South Africa illustrate inevitable tradeoffs when choosing among a variety of interventions to decrease cervical cancer mortality, and demonstrate how these methods can facilitate a bridge between research and health policy.