Improving the effectiveness of cervical cancer screening: Managing positive high-risk human papillomavirus results.

Introduction: Good compliance of the management of abnormal results is important for effective cervical screening. This study investigated the rate of surveillance and follow-up outcomes for human papillomavirus (HPV)-positive women in cervical screening. Method: Women on surveillance by repeat HPV testing were identified in a prospectively managed database. Data retrieved included women's age, country residence status, history of colposcopy, HPV-DNA status on the first and repeat tests, dates of follow-up during the 5 years since the initial screening, and histological diagnosis of cervical lesions. The main outcome measures were compliance rate for repeat HPV testing, regression and persistence rates of HPV subtypes, and detection rate of high-grade lesions (CIN2+). Results: This analysis included 680 residents in the community, mean age 44.8 (95% confidence interval 20.1-69.5) years. The compliance rate of repeat testing was 28.2% at 12 months and, cumulatively, 42.8% for the entire 5-year follow-up period. The rates were unaffected by age (P=0.5829) nor prior colposcopy (P=0.1607). There were 5 (1.7%) cases of CIN2+ detected. Of 391 women on longitudi-nal follow-up, 194 (60.8%) cleared their HPV infection. Some women with multiple HPV infection cleared 1 but not the other subtype(s). Thus, the regression rate was 90.3% for HPV-16, 87.0% for HPV-18 and 65.2% for HPV-12-others (P=0.001). The annualised HPV regression rates were similar for HPV subtypes and for each follow-up year. Conclusion: Surveillance of HPV positivity is clinically important for detecting high-grade lesions. Despite a high regression rate of HPV, surveillance hesitancy is a serious weakness in routine cervical screening.

Clinical efficacy of primary human papillomavirus (HPV) screening with partial genotyping for HPV-16 and HPV-18 subtypes in women from 25 years old.

Introduction: Cervical screening programmes differ in the age of women recommended for primary human papillomavirus (HPV) testing. This study aims to determine the clinical efficacy and impact of 14-high-risk HPV DNA testing for women from 25 years old. Method: This was a retrospective analysis of data collected prospectively from women 25 years or older who attended hospital-based gynaecology clinics for cervical screening. Women with history of cervical neoplasia or abnormal cytology were excluded. High-risk HPV DNA testing with partial genotyping for HPV-16 and HPV-18 were performed on cobas 4800 System (Roche Diagnostics International AG, Rotkreuz, Switzerland). Women tested positive for the 12 other high-risk HPV subtypes (HPV-12 other) had a reflex cytology test. Positive screening included positive for HPV-16 and/or HPV-18, HPV-12 other with cytology abnormalities equal to or greater than atypical squamous cells of undetermined significance, and repeated positive HPV at 12 months. HPV detection and colposcopy referral rates, and detection of high-grade neoplasia were determined. Results: Of 10,967 women studied, 822 (7.50%) were HPV DNA positive. The overall discharge rate to routine screening according to screening protocol was 93.1%. Colposcopy referral rate was 4.4%. The screening detected 41 cervical intraepithelial neoplasia grade 2+ (CIN2+) (0.37%) and 31 (0.28%) CIN3+. The number of colposcopies needed per case of CIN2+ was 9.5, similar for women below and above 30 years old. The number of colposcopies needed per case of CIN3+ for HPV-16 positivity was 8.5, compared to 17.0 for other categories (P=0.040). Colposcopy efficacy was similar for HPV-18 and HPV-12 other positivity with abnormal cytology. Conclusion: Taking CIN2+ detection and colposcopy referral rate as endpoints, HPV testing in Singapore can be extended to include women from 25 years old.

Cost-effectiveness of two-dose human papillomavirus vaccination in Singapore.

INTRODUCTION: Cervical cancer is the tenth most common cancer and the eighth most frequent cause of death among women in Singapore. As human papillomavirus (HPV) infection is the necessary cause of cervical cancer, the risk of cervical cancer can be substantially reduced through vaccination. This study was conducted to evaluate the cost-effectiveness of two-dose HPV vaccination as part of a national vaccination programme for 12-year-old girls in Singapore, from the perspective of the healthcare payer. METHODS: A lifetime Markov cohort model was used to evaluate the cost-effectiveness of introducing the AS04-adjuvanted HPV-16/18 vaccine (AS04-HPV-16/18v) to the current cervical screening programme in Singapore. Furthermore, the cost-effectiveness of the AS04-HPV-16/18v was compared with the HPV-6/11/16/18 vaccine (4vHPV). Model inputs were derived from local data, where possible, and validated by clinical experts in Singapore. RESULTS: Introduction of the AS04-HPV-16/18v in Singapore was shown to prevent 137 cervical cancer cases and 48 cervical cancer deaths when compared with screening alone. This resulted in an incremental cost-effectiveness ratio of SGD 12,645 per quality-adjusted life year (QALY) gained, which is cost-effective according to the World Health Organization threshold for Singapore. When discounted at 3%, AS04-HPV-16/18v was dominant over 4vHPV, with cost savings of SGD 80,559 and 28 additional QALYs gained. In the one-way sensitivity analysis, AS04-HPV-16/18v remained cost-effective compared with screening alone and dominant compared with 4vHPV. CONCLUSION: AS04-HPV-16/18v is the most cost-effective choice for reducing the burden of cervical cancer through universal mass vaccination for 12-year-old girls in Singapore.

Detection Rate of High-Grade Cervical Neoplasia and Cost-Effectiveness of High-Risk Human Papillomavirus Genotyping with Reflex Liquid-based Cytology in Cervical Cancer Screening.

INTRODUCTION: This study aimed to determine the prevalence of cervical intraepithelial neoplasia grade 3 or worse (≥CIN3) and cost-effectiveness of human papillomavirus (HPV) genotyping with reflex liquid-based cytology (LBC) for cervical cancer screening in Singapore. MATERIALS AND METHODS: Women who were ≥25 years old and undertook co-testing with LBC and HPV-genotyping (Cobas-4800, Roche, USA) for HPV-16, HPV-18 and 12 high-risk HPV types in a single institution were studied retrospectively. A single cervical smear in ThinPrep® PreservCyt® solution (Hologic, USA) was separated for tests in independent cytology and molecular pathology laboratories. The results were reviewed by a designated gynaecologist according to institutional clinical management protocols. Those who tested positive for HPV-16 and/or HPV-18 (regardless of cytology results), cytology showing low-grade squamous intraepithelial lesions (LSIL) or high-grade SIL (HSIL), or atypical squamous cells of undetermined significance (ASCUS) with positive 12 high-risk HPV types were referred for colposcopy. Colposcopy was performed by experienced colposcopists. Cervical biopsy, either directed punch biopsies or excisional biopsy, was determined by a colposcopist. The diagnosis of ≥CIN3 was reviewed by a gynaecologic pathologist. Cost-effectiveness of HPV-based screening in terms of disease and financial burden was analysed using epidemiological, clinical and financial input data from Singapore. RESULTS: Of 1866 women studied, 167 (8.9%) had abnormal cytology (≥ASCUS) and 171 (9.2%) tested positive for high-risk HPV. Twenty-three CIN were detected. Three of the 10 ≥CIN3 cases had negative cytology but positive HPV-16. Compared to cytology, HPV genotyping detected more ≥CIN3 (OR: 1.43). HPV+16/18 genotyping with reflex LBC was superior in terms of cost-effectiveness to LBC with reflex HPV, both for disease detection rate and cost per case of ≥CIN2 detected. CONCLUSION: Compared to cytology, HPV+16/18 genotyping with reflex LBC detected more ≥CIN3 and was cost-effective for cervical screening in Singapore.

The clinical and economic benefits of school-based quadrivalent HPV vaccination in Singapore.

OBJECTIVE: To investigate the clinical and economic impacts of school-based administration of the quadrivalent HPV vaccine. METHODS: A retrospective health-economic analysis was conducted using data collected in Singapore between 2004 and 2005. A dynamic transmission model was adapted for universal vaccination that provided 80% coverage among students aged 11-12 years. Strategy 1 involved only girls, with a 5-year catch-up vaccination to provide 50% coverage among those aged 13-17 years. Strategy 2 included both girls and boys with no catch-up vaccination. Outcomes included the predicted incidence of HPV-related disease over 100 years. RESULTS: Current coverage was assumed to be 5%. Strategy 1 would reduce cervical intraepithelial neoplasia grade 1 (CIN1) by 63.8%, cervical intraepithelial neoplasia grade 2-3 (CIN2-3) by 62.9%, cervical cancer by 50.9%, and genital warts by 78.0% (female individuals) and 73.6% (male individuals). Strategy 2 would reduce CIN1 by 64.0%, CIN2-3 by 63.1%, cervical cancer by 50.7%, and genital warts by 79.9% (female individuals) and 80.1% (male individuals). The incremental cost-effectiveness ratio was S$12 464 for strategy 1 and $27 837 for Strategy 2. These values decreased to $7477 and $22 574, respectively, if a two-dose regimen was adapted. CONCLUSION: School-based quadrivalent HPV vaccination offered clinical and economic benefits, and is cost-effective in Singapore.

Targeted silencing of MLL5ß inhibits tumor growth and promotes gamma-irradiation sensitization in HPV16/18-associated cervical cancers.

We previously identified a novel MLL5 isoform, MLL5ß, which was essential for E6 and E7 transcriptional activation in HPV16/18-associated cervical cancers. In this report, we investigated the potential of RNAi-mediated silencing of MLL5ß through the use of MLL5ß-siRNA as a novel therapeutic strategy for HPV16/18-positive cervical cancer. We observed concurrent downregulation of E6 and E7 after MLL5ß silencing, leading to growth inhibition via the activation of apoptosis and senescence in the HeLa cell model. This corresponded with the enhanced antitumor effects of MLL5ß-siRNA compared with E6- or E7-siRNA single treatments. Significant reduction in tumor size after MLLß-siRNA treatment in the HeLa xenograft tumor model further emphasized the importance of MLL5ß in HPV16/18-associated tumor growth and the potential of RNAi therapeutics that target MLL5ß. We also identified MLL5ß as a modulator of gamma-irradiation (IR) sensitization properties of cisplatin. We observed that while MLL5ß silencing alone was enough to evoke cisplatin-like IR sensitization in tumor cells in vitro, overexpression of MLL5ß inhibited the ability of cisplatin to sensitize HeLa cells to IR-induced cytotoxicity. MLL5ß-siRNA-IR cotreatment was also observed to enhance tumor growth inhibition in vivo. Taken together, our findings highlight the potential of targeted silencing of MLL5ß via the use of MLL5ß-siRNA as a novel therapeutic strategy and propose that MLL5ß-siRNA could be a viable alternative for cisplatin in the current cisplatin-based chemotherapeutics for HPV16/18-associated cervical cancers.

Evidence for ethnic and environmental contributions to frequency of ovarian clear cell carcinoma.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) is reportedly more common in Asians than Caucasians. We investigated the epidemiology of OCCC in an Asian population. MATERIALS AND METHODS: Cases of epithelial ovarian cancer (EOC) diagnosed between January 2004 and December 2009 in a gynaecologic oncology unit were studied retrospectively. Patient details and tumour characteristics were retrieved from hospital records and tested for their association with OCCC by univariate and binomial logistic regression analysis. A time trend in the proportion of OCCC among EOC was computed with data from the National Cancer Registry of Singapore (1968-2006). RESULTS: The institutional cohort of 341 cases included 81 OCCC and 260 non-OCCC EOC. Independent risk factors for OCCC were nulliparity (OR = 1.36) and endometriosis (OR = 4.87). Compared with other EOC, OCCC was significantly larger in tumour size (13.5 vs. 11.3 cm), more frequently located unilaterally (84.3 vs. 65.5%), diagnosed at FIGO stage-1 (63.0 vs. 33.9%) and negative for serum CA125 (34.2 vs. 8.2%), and less often (53 vs. 85%) associated with a positive Risk of Malignancy Index. Nation-wide statistics revealed a steady increase in the proportion of OCCC among EOC from 5.2 to 13.4% between 1968 and 2006. The frequency of OCCC in Singapore was higher than American Whites, similar to American Asians but lower than Japanese. CONCLUSION: The difference in epidemiologic and tumour characteristics between OCCC and other EOC was nondiscriminatory. Three distinct ethnic-related clusters of frequency distribution globally and the rising trend in proportion of OCCC in Singapore suggested that ethnic-genetic predisposition and economy-related environmental factors contributed to development of OCCC.

Prevalence of cervical human papillomavirus infection in healthy women is related to sexual behaviours and educational level: a cross-sectional study.

This study reports the prevalence and risk factors of human papillomavirus (HPV) infection in healthy women in Singapore. Demography, education, sexual and reproductive history and cigarette smoking habits were obtained from a cross-sectional population of healthy women and girls aged above 12 years of age. Cervical or vaginal cytology samples were investigated for 37 known anogenital HPV subtypes using the linear array PCR method. Chi square statistics were used to test for associations of individual epidemiological factors with HPV infection. Independent risk factors were identified with binomial logistic regression analysis. Of 891 subjects, the prevalence of HPV infection was 9.31% (83/891 women) for any-type HPV and 5.05% (46/891 women) for the high-risk HPV (hrHPV). Of 30 HPV subtypes detected, the most prevalent genotypes in descending order of frequency were subtypes 51, 16, 52, 58 and 66 for hrHPV and subtypes 62, 61, 84, 72 and 53 for the low-risk HPV. This frequency distribution of HPV subtypes was different from reports from other countries within Asia. Forty-six virgins studied tested negative for HPV infection. Significant independent risk factors for any-type HPV infection were multiple sexual partners (adjusted OR 1.4) and low (≤6 years) educational level (adjusted OR 4.0). The distribution of HPV subtypes in healthy women varies between different countries within Asia. In Singapore, the prevalence of HPV infection was 9.31% and was related to penetrative sexual intercourse, multiple sexual partners and low educational level.

HER2 amplification and clinicopathological characteristics in a large Asian cohort of rare mucinous ovarian cancer.

Mucinous epithelial ovarian cancer has a poor prognosis in the advanced stages and responds poorly to conventional chemotherapy. We aim to elucidate the clinicopathological factors and incidence of HER2 expression of this cancer in a large Asian retrospective cohort from Singapore. Of a total of 133 cases, the median age at diagnosis was 48.3 years (range, 15.8-89.0 years), comparatively younger than western cohorts. Most were Chinese (71%), followed by Malays (16%), others (9.0%), and Indians (5%). 24% were noted to have a significant family history of malignancy of which breast and gastrointestinal cancers the most prominent. Majority of the patients (80%) had stage I disease at diagnosis. Information on HER2 status was available in 113 cases (85%). Of these, 31 cases (27.4%) were HER2+, higher than 18.8% reported in western population. HER2 positivity appeared to be lower among Chinese and higher among Malays patients (p = 0.052). With the current standard of care, there was no discernible impact of HER2 status on overall survival. (HR = 1.79; 95% CI, 0.66-4.85; p = 0.249). On the other hand, positive family history of cancer, presence of lymphovascular invasion, and ovarian surface involvements were significantly associated with inferior overall survival on univariate and continued to be statistically significant after adjustment for stage. While these clinical factors identify high risk patients, it is promising that the finding of a high incidence of HER2 in our Asian population may allow development of a HER2 targeted therapy to improve the management of mucinous ovarian cancers.

Uterine leiomyosarcoma in asian patients: validation of the revised Federation of gynecology and obstetrics staging system and identification of prognostic classifiers.

BACKGROUND: In 2008, the Federation of Gynecology and Obstetrics (FIGO) revised their 1988 staging system for uterine leiomyosarcomas. In this article, we compare performance of the 2008 and 1988 FIGO systems. METHODS: Individual case data were manually culled. Staging was retrospectively assessed according to revised and 1998 FIGO criteria. Overall survival distribution was assessed by the Kaplan-Meier method. Harrell's concordance index was used to assess the discriminative ability of a fitted Cox model to predict overall survival. RESULTS: A total of 110 cases of uterine leiomyosarcomas were reviewed and data from 88 patients were analyzed. In all, 71% of cases were classified as stage I, 7% as stage II, 3% as stage III, and 19% as stage IV under the revised FIGO staging system. Nine patients (10.2%) were downstaged and none were upstaged. The revised FIGO system did not show a significant improvement over the 1988 FIGO system in the ability to discriminate the risk of death of patients between stages, with concordance indexes of 0.70 and 0.71, respectively. Most patients were classified as stage I with age, tumor grade, tumor size, and lymphovascular invasion as prognostic factors. CONCLUSION: The 2008 revised FIGO staging system for uterine leiomyosarcomas does not perform better than the 1988 system for uterine endometrial carcinomas. A better staging system is needed for these cases.

Health and economic burden of HPV-related diseases in Singapore.

OBJECTIVE: To assess the health and economic burden of human papillomavirus (HPV)-related diseases (cervical cancer, cervical intraepithelial neoplasia (CIN) 1/2/3, and genital warts) in Singapore over a period of 25 years beginning in 2008. METHODS: Incidence-based modeling was used to estimate the incidence cases and associated economic burden, with the assumption that age-stratified incidence rates will remain the same throughout the period of 25 years. The incidence rates in 2008 were projected based on data obtained from the National Cancer Registry for cervical cancer, and from a combination of published data and hospital registry review for CIN1/2/3 and genital warts. The population growth rate was factored into the projection of incidence cases over time. Direct cost data per cervical cancer and per CIN1/2/3 case were obtained from the financial database of large local hospitals while cost data for genital warts were obtained from the National Skin Center; these costs were multiplied by the number of incidence cases to produce an aggregate estimate of the economic burden over the 25-year period (in 2008 Singapore dollars) using a 3% discount rate. RESULTS: The total number of incidence cases of HPV-disease over 25 years beginning in 2008 was estimated to be 60,183, including 8,078 for cervical cancer, 11,685 for CIN 2/3, 8,849 for CIN1, and 31,572 for genital warts. The estimated total direct cost was 83.2 million Singapore Dollars over 25 years: 57.6 million attributable to cervical cancer, 13.0 million to CIN2/3, 6.83 million to CIN1, and 5.70 million to genital warts. CONCLUSION: HPV-related diseases are expected to impose significant health and economic burden on the Singapore healthcare resources in the next 25 years.

Cervical cancer in the human papillomavirus vaccination era.

PURPOSE OF REVIEW: To evaluate the potential changes in the epidemiology of cervical cancer based on recently emerged information from mass vaccination programs beyond clinical trials. RECENT FINDINGS: Limited sensitivity and unequal access to screening have resulted in an imbalance in distribution of the burden of cervical cancer between developed and developing countries, between metropolitan and rural areas in developed countries, and among women from different ethnic groups. In screened populations, there is a relative increase in incidence of cervical cancer in young and elderly women, and an increased proportion of adenocarcinoma. A high coverage of the target population has been achieved in human papillomavirus (HPV) vaccination programs in many countries. After 3 years of mass vaccination of adolescent girls, surveillance data in Australia confirmed a significant reduction in high-grade abnormalities for girls aged 18 years and below. SUMMARY: HPV vaccination is more feasible than cytology screening for universal implementation across geographic sectors and demographic groups within individual countries and over the world. The high vaccine efficacy should significantly reduce the total burden and unequal distribution of invasive cervical cancer, including adenocarcinoma hitherto observed. These epidemiological changes provoke consideration for appropriate modifications of the current screening program.

A novel MLL5 isoform that is essential to activate E6 and E7 transcription in HPV16/18-associated cervical cancers.

Human papillomavirus (HPV) is the primary cause of human cervical cancer. The viral proteins E6 and E7 are essential to transform noncancerous epithelial cells into cancerous carcinomas by targeting key tumor suppressors p53 and retinoblastoma (Rb) proteins, respectively, but the cellular factors involved in E6 and E7 transcription themselves are incompletely understood. In this study, we defined a novel isoform of the mixed lineage leukemia 5 gene (MLL5ß) as a specific and critical regulator of E6 and E7 transcription in cervical carcinoma cells. MLL5ß is present in HPV16/18-positive cells including human primary cervical carcinoma specimens. Interaction of MLL5ß with the AP-1-binding site at the distal region of the HPV18 long control region led to activation of E6/E7 transcription. Conversely, RNA interference-mediated knockdown of MLL5ß downregulated both E6 and E7 expression. MLL5ß downregulation was sufficient to restore p53 protein levels and reduce Rb phosphorylation, thereby reactivating apoptosis and cell-cycle checkpoints. By defining this novel MLL5ß isoform and its specific critical role in activating E6/E7 gene transcription in HPV16/18-induced cervical cancers, our work highlights the potential of MLL5ß as a biomarker and new therapeutic target in primary HPV-induced cervical cancers.

Cost-effectiveness of different human papillomavirus vaccines in Singapore.

BACKGROUND: Human papillomavirus (HPV) vaccines are widely available and there have been studies exploring their potential clinical impact and cost-effectiveness. However, few studies have compared the cost-effectiveness among the 2 main vaccines available - a bivalent vaccine against HPV 16/18, and a quadrivalent vaccine against 6/11/16/18. We explore the cost-effectiveness of these two HPV vaccines in tropical Singapore. METHODS: We developed a Markov state-transition model to represent the natural history of cervical cancer to predict HPV infection, cancer incidence, mortality, and costs. Cytologic screening and treatment of different outcomes of HPV infection were incorporated. Vaccination was provided to a cohort of 12-year old females in Singapore, followed up until death. Based on available vaccines on the market, the bivalent vaccine had increased effectiveness against a wider range of HPV types, while the quadrivalent vaccine had effectiveness against genital warts. Incremental cost-effectiveness ratios (ICER) compared vaccination to no-vaccination, and between the two vaccines. Sensitivity analyses explored differences in vaccine effectiveness and uptake, and other key input parameters. RESULTS: For the no vaccination scenario, 229 cervical cancer cases occurred over the cohort's lifetime. The total discounted cost per individual due to HPV infection was SGD$275 with 28.54 discounted life-years. With 100% vaccine coverage, the quadrivalent vaccine reduced cancers by 176, and had an ICER of SGD$12,866 per life-year saved. For the bivalent vaccine, 197 cancers were prevented with an ICER of $12,827 per life-year saved. Comparing the bivalent to the quadrivalent vaccine, the ICER was $12,488 per life-year saved. However, the cost per QALY saved for the quadrivalent vaccine compared to no vaccine was $9,071, while it was $10,392 for the bivalent vaccine, with the quadrivalent vaccine dominating the bivalent vaccine due to the additional QALY effect from reduction in genital warts. The overall outcomes were most sensitive to vaccine cost and coverage. CONCLUSION: HPV vaccination is a cost-effective strategy, and should be considered a possible strategy to reduce the impact of HPV infection.

The prevalence and significance of high-risk human papillomavirus DNA test in southern Malaysia and Singapore.

AIM OF STUDY: To investigate the prevalence of high-risk human papillomavirus (HPV) and its associated cytological abnormalities among women attending cervical screening clinics in southern Malaysia and Singapore. METHOD: Laboratory results of Hybrid Capture-II (Digene) HPV DNA and liquid-based cytology tests of consecutive women who had screening performed between January 2004 and December 2006 were studied retrospectively. RESULTS: Of 2364 women studied, the overall prevalence of high-risk HPV DNA detection rate was 25.6%. The prevalence peaked at 49.1% for women between 20 and 24 years old and declined to 23% among women between the age of 30 and 49 years. A small second peak of prevalence rate of 30% was observed among women above the age of 50 years old. 76.1% of the high-risk HPV infection regressed within the study period. An incidence infection rate of 16% was noted among a small group of women who had a second HPV DNA test. A total of 1153 women had both the HPV DNA and the cytology tests. Cytological abnormality (ASCUS or more) was detected in 8.9% in HPV DNA-positive group and in 3.1% in HPV DNA-negative group (P < 0.001). The risk ratio for HSIL was 9.8 for HPV-positive women compared to HPV-negative women. The prevalence of cytological abnormalities increased with increasing age of the women. CONCLUSION: The epidemiology and clinical impact of high-risk HPV infection for women in Southern Malaysia and Singapore were indistinguishable from experience elsewhere. The apparent moderately high incidence of cervical cancer was explainable by suboptimal screening program.

Epidemiology of human papillomavirus infection and cervical cancer and future perspectives in Hong Kong, Singapore and Taiwan.

Hong Kong, Singapore and Taiwan are three island states that are newly emerged affluent economic areas in Asia. The majority of the populations are ethnically Chinese with a total population of 6.98, 4.5 and 23 million, respectively. Cervical cancer has been declining over the last thirty years in all three states and is largely attributable to widespread opportunistic cervical cancer screening. The age-standardized incidence rates of cervical cancer are 9.6 per 100,000 women in Hong Kong in 2004, 10.6 per 100,000 women in Singapore in 2002 and 18.6 per 100,000 women in Taiwan in 2003. High prevalence of human papillomavirus (HPV) was observed in all three states. In cervical cancer, HPV 16 and 18 are the two most prevalent HPV types, but HPV 58 and 52 are also highly prevalent in these three states. Important epidemiological risk factors for invasive cervical cancer include smoking and age at sexual debut for women, although this is changing towards an earlier age. Of the three states, Taiwan was the first to have a comprehensive national screening programme in 1995 followed by Hong Kong in 2002 and Singapore in 2004. Women in these three states are well aware of cervical cancer and the preventative means by Pap smear screening, although their awareness and understanding of the role of HPV in cervical carcinogenesis is low. Prophylactic HPV vaccines have been licensed in the three states. Routine comprehensive public vaccination programme for adolescent girls has yet to be adopted by the governmental agency, despite an affirmative recommendation by medical professional bodies.

Recommendations for cervical cancer prevention in Asia Pacific.

Asia Oceania includes countries from both the Asia Pacific region and Australasia, which cover very diverse geographical areas and populations as well as bearing 52% of the cervical cancer burden in the world. Human papillomavirus (HPV) genotype distribution in women with normal cytology varies between countries in this region, as well as with the distribution typically observed in worldwide estimates or in Western countries. HPV-16 remains the predominant oncogenic type for high-grade cervical dysplasia and cervical cancer across the region, and HPV-18 is generally among the five most common types. HPV-58 is commonly found in cervical cancer as well as in women with normal cytology, and HPV-31, 33 and 35 are relatively less frequent in these regions compared to the West. While screening programmes have been proposed and implemented in several populations, successful programmes are rather limited and the majority of countries still have no or minimal screening services. Prophylactic HPV vaccination will only be feasible when it becomes affordable, thus the current priority and the short-term goal for cervical cancer control is to identify feasible and effective screening measures, and to find the most effective way to combine vaccination with sustainable screening programmes. This Regional Report has carefully described the disease burden of HPV and cervical cancer and the current situations in cervical cancer prevention for many countries in the Asia Oceania region. These data identify the many challenges and opportunities to be considered for policy decisions for cervical cancer control. Furthermore, this report presents the results of advanced decision analytic models calibrated to countries in the region that provide early insight into what strategies are most promising and those likely to be cost-effective and affordable. It thus provides a synthesis of the available evidence-based scientific information, in the context of a significant and systematic international review, that is likely to be useful to governments and public health providers.