The impact of cytology screening and HPV vaccination on the burden of cervical cancer

Retrospective analysis of the incidence and predictive factors of parametrial involvement in FIGO IB1 cervical cancer

BACKGROUND AND OBJECTIVES

Radical surgery is the standard primary treatment for patients with stage IB1 (FIGO 2009 staging) cervical cancer due to latent parametrial involvement. Recent studies suggested that less radical surgery was applicable for patients with no or low risk of parametrial involvement. In this study, we aimed to determine the incidence and possible predictive factors of parametrial involvement in patients with stage IB1 cervical cancer so as to evaluate whether less radical surgery was suitable for selected patients.

METHODS

Clinical data of patients who underwent type C radical hysterectomy with pelvic lymphadenectomy and diagnosed as stage IB1 cervical cancer at Union Hospital, Wuhan, China from October 2014 to December 2017 were collected and analysed retrospectively. The incidence of parametrial involvement was calculated and the risk factors for parametrial involvement were evaluated by univariate and multivariate logistic regression.

RESULTS

Among 282 eligible patients, 33 (11.7%) had parametrial involvement. Postmenopause, lymphovascular space invasion (LVSI), lymph node metastasis (LNM), deep stromal invasion (outer 1/3) and tumor size larger than 2 cm were statistically associated with parametrial involvement. Multivariate analysis showed that LNM (OR = 11.431; 95%CI: 3.455 - 37.821), deep stromal invasion (OR = 6.080; 95%CI: 1.814 - 20.382) and LVSI (OR = 7.147; 95%CI: 1.863-27.411) remained as independent risk factors for parametrial involvement in patients with stage IB1 cervical cancer.

CONCLUSIONS

The incidence of parametrial involvement in stage IB1 cervical cancer is non-negligible. Only LNM, LVSI and deep stromal invasion were independent predictors, which were not easy to evaluate accurately before surgery. Less radical surgery requires modified pre-treatment evaluation methods and prospective data support.

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.

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.

Incidence, Trends and Ethnic Differences of Oropharyngeal, Anal and Cervical Cancers: Singapore, 1968-2012

In recent decades, several Western countries have reported an increase in oropharyngeal and anal cancers caused by human papillomavirus (HPV). Trends in HPV-associated cancers in Asia have not been as well described. We describe the epidemiology of potentially HPV-related cancers reported to the Singapore Cancer Registry from 1968-2012. Analysis included 998 oropharyngeal squamous cell carcinoma (OPSCC), 183 anal squamous cell carcinoma (ASCC) and 8,019 invasive cervical cancer (ICC) cases. Additionally, 368 anal non-squamous cell carcinoma (ANSCC) and 2,018 non-oropharyngeal head and neck carcinoma (non-OP HNC) cases were included as comparators. Age-standardized incidence rates (ASR) were determined by gender and ethnicity (Chinese, Malay and Indian). Joinpoint regression was used to evaluate annual percentage change (APC) in incidence. OPSCC incidence increased in both genders (men 1993-2012, APC = 1.9%, p<0.001; women 1968-2012, APC = 2.0%, p = 0.01) and was 5 times higher in men than women. In contrast, non-OP HNC incidence declined between 1968-2012 among men (APC = -1.6%, p<0.001) and women (APC = -0.4%, p = 0.06). ASCC and ANSCC were rare (ASR = 0.2 and 0.7 per 100,000 person-years, respectively) and did not change significantly over time except for increasing ANSCCs in men (APC = 2.8%, p<0.001). ICC was the most common HPV-associated cancer (ASR = 19.9 per 100,000 person-years) but declined significantly between 1968-2012 (APC = -2.4%). Incidence of each cancer varied across ethnicities. Similar to trends in Western countries, OPSCC incidence increased in recent years, while non-OP HNC decreased. ICC remains the most common HPV-related cancer in Singapore, but Pap screening programs have led to consistently decreasing incidence.

Modeling the impact of screening policy and screening compliance on incidence and mortality of cervical cancer in the post-HPV vaccination era

BACKGROUND

In Norway, pap smear screening target women aged 25-69 years on a triennial basis. The introduction of human papillomavirus (HPV) mass immunization in 2009 raises questions regarding the cost-saving future changes to current screening strategies.

METHODS

We calibrated a dynamic HPV transmission model to Norwegian data and assessed the impact of changing screening 20 or 30 years after vaccine introduction, assuming 60 or 90% vaccination coverage. Screening compliance among vaccinated women was assumed at 80 or 50%. Strategies considered: (i) 5-yearly screening of women of 25-69 years, (ii) 3-yearly screening of women of 30-69 years and (iii) 3-yearly screening of women of 25-59 years.

RESULTS

Greatest health gains were accomplished by ensuring a high vaccine uptake. In 2060, cervical cancer incidence was reduced by an estimated 36-57% compared with that of no vaccination. Stopping screening at the age of 60 years, excluding opportunistic screening, increased cervical cancer incidence by 3% (2060) compared with maintaining the current screening strategy, resulting in 1.0-2.4% extra cancers (2010-2060). The 5-yearly screening strategy elevated cervical cancer incidence by 30% resulting in 4.7-11.3% additional cancers.

CONCLUSION

High vaccine uptake in the years to come is of primary concern. Screening of young women <30 years remains important, even under the conditions of high vaccine coverage.