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    2019-08-16


    Declaration of interests
    Author contribution statement
    Acknowledgements
    Introduction Cervical cancer has been previously estimated to be the fourth most common cancer and the fourth most common cause of cancer death for women worldwide in 2012, with an estimated 528,000 new cases and 266,000 deaths annually [1]. In Vietnam, prior estimates suggest it was the fourth most common cancer in women with 5146 new cases and 2423 cervical cancer deaths in 2012 [1]. Several pilot cervical screening projects have been conducted to evaluate different cervical screening strategies over the last few decades, including use of cytology and visual inspection with acetic ITF2357 (Givinostat) (VIA). However, cervical screening in Vietnam is currently opportunistic, and findings from a survey in 2003 showed that approximately 4–6% of women across urban and rural regions have been screened [2]. In 2011, the Vietnam Ministry of Health (MOH) issued guidelines for screening, diagnosis and treatment of precancerous lesions as secondary prevention for cervical cancer, in which various screening techniques including VIA, cytology and HPV DNA testing were recommended [3]. The guidelines recommended cervical screening with cytology and VIA tests for women aged 21–70 years, with particular focus on those 30–50 years. A 2-yearly screening frequency is recommended, extending to every three years for women with three consecutive negative tests. Based on these guidelines, several provinces in Vietnam have been using VIA as a cervical screening test [4], however, a national organized cervical screening program has not yet been established. Although human papillomavirus (HPV) vaccination has been shown to effectively prevent cervical precancer, the vaccine has not yet been introduced into the Vietnamese national immunization program. A demonstration project was conducted in four districts of two provinces in 2008–2010 for approximately 7000 pre-adolescent girls (aged 11–13 years) to assess the acceptability, feasibility, and delivery cost of the vaccine [5,6]. While this pilot project showed a high level of acceptability and coverage (96.1% of the targeted population achieved) [5], the additional costs of delivering a new vaccine to a new population group (i.e. to pre-adolescents rather than young children) poses a challenge [7]. Unfortunately, from 2017, Vietnam is no longer eligible for support from Gavi, the Vaccine Alliance, and the national government faces competing demands for funding for early childhood vaccines [8]. HPV has been identified as the necessary cause of virtually all cervical cancers [9,10]. HPV DNA is found in virtually all invasive squamous cervical cancers in well-controlled studies [11,12]. In addition, studies designed to detect prevalent histologically-confirmed cervical intraepithelial neoplasia, grades 2 or 3 (CIN2/3), alternatively referred to as ‘HSIL’ (high-grade squamous intraepithelial lesions), provide an important indicator of the prevalence of high-grade precursor lesions that precede the development of invasive cervical cancer [13]. Therefore, in unscreened populations study-ascertained prevalence of HPV infection and HSIL can be considered to be surrogate markers for the cervical cancer burden [14]. There are also factors which are likely to be associated with the transmission of HPV (correlates of HPV infection) and the progression of HPV infection to cervical cancer (cofactors for HPV progression), which are also important to consider when examining the likely patterns of cervical cancer in a population. International pooled analyses have identified the correlates of HPV infection as: age at first sexual intercourse, number of lifetime sex partners, and any STI exposure [15,16], and that oral contraceptive use, smoking, parity, and age at first full term pregnancy are cofactors for cervical cancer development [[17], [18], [19]].