1.1. Background
Cervical cancer is a leading cause of mortality among women. In 2020, an estimated 604 000 women were diagnosed with cervical cancer worldwide and about 342 000 women died from the disease. Cervical cancer is the most commonly diagnosed cancer in 23 countries and is the leading cause of cancer death in 36 countries. The vast majority of these countries are in sub-Saharan Africa, Melanesia, South America, and South-Eastern Asia (1).
In May 2018, Dr Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO), issued a call to action for the elimination of cervical cancer. A WHO Global Strategy to accelerate the elimination of cervical cancer as a public health problem was presented and unanimously endorsed by the Seventy-third World Health Assembly in August 2020. Subsequently, WHO officially launched the Global Strategy to accelerate the elimination of cervical cancer on 17 November 2020.1
The targets of the Global Strategy are to achieve, by 2030:
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90% of girls fully vaccinated with human papillomavirus (HPV) vaccine by age 15 years
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70% of women screened with a high-performance test by 35 years of age and again by 45 years of age
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90% of women identified with cervical disease receive treatment (90% of women with pre-cancer treated, and 90% of women with invasive cancer managed) (2).
In the context of this Global Strategy, countries are updating their protocols for the prevention of cervical cancer and for the care and treatment of affected women. Cervical cancer prevention also plays an integral role in reaching the Sustainable Development Goals (SDGs), both for health (SDG 3) and gender equality (SDG 5).
To prevent cervical cancer, women can be screened using various tests to identify those who have or are at risk of cervical pre-cancer (see ). Cervical intraepithelial neoplasia (CIN) is characterized by cellular changes in the transformation zone of the cervix. CIN is typically caused by infections with HPV, especially the high-risk HPV types such as strains 16 and 18 (these two strains cause more than 70% of cervical cancers) (3, 4). CIN1 lesions – also referred to as low-grade squamous intraepithelial lesions – are morphological correlates of HPV infections. CIN2/3 lesions – also referred to as high-grade squamous intraepithelial lesions – are correlates of cervical pre-cancers that, if left untreated, may progress into cervical cancer (for further details, refer to Chapter 1 of WHO’s Comprehensive cervical cancer control guidance [5]).
Three approaches to cervical cancer screening and future tests.
The traditional method to screen women for cervical cancer has been cytology (the Papanicolaou test, also known as the Pap smear or smear test). When cytology results are positive, the diagnosis is confirmed by colposcopy, and appropriate treatment is informed by biopsy of suspicious lesions for histological diagnosis.
Newer screening tests introduced in the last 15 years include visual inspection with acetic acid (VIA), and molecular tests, mainly high-risk HPV DNA-based tests,2 which are suitable for use in all settings (). More recently, even newer tests and techniques have been developed: (i) other molecular tests such as those based on HPV mRNA, oncoprotein detection or DNA methylation; (ii) more objective tests performed on cytological samples such as p16/Ki-67 dual staining; and (iii) more advanced visual inspection tests based on artificial intelligence/machine learning platforms (e.g. automated visual evaluation of digital images) (6–9).
1.2. HPV mRNA technology and interpretation of test results
The focus of this edition of the updated guideline is the use of HPV mRNA tests (HPV E6/E7 messenger RNA detection) for HPV detection as an alternative method to HPV DNA tests for HPV detection. The virus infecting the basal cell layer of the cervical epithelium is comprised of a double-stranded DNA at its core and a protein coat (capsid). The DNA tests detect either the viral DNA through hybridization technique or a highly conserved region of the L1 capsid protein or of the E genes using polymerase chain reaction (PCR). Hence, HPV DNA tests detect the presence of the virus by detecting the viral DNA. The HPV mRNA tests detect transcripts of the viral E6 and E7 oncoproteins, which are responsible for HPV-mediated oncogenic transformation of epithelial cells.
Persistent infection from any of the high-risk types of HPV is essential for cervical oncogenesis. The process of carcinogenesis starts with the virus particles entering the basal layer of the cervical epithelium and integration of their DNA with the host cellular DNA. As the carcinogenic process advances, the E6 and E7 oncoproteins are expressed, and these proteins are primarily responsible for neoplastic transformation. The E7 protein can bind and degrade retinoblastoma (pRb) tumour suppressor protein, which initiates uncontrolled activation of the cell cycle. The E6 protein degrades p53 (another tumour suppressor protein), inhibiting apoptosis (programmed cell death), and upregulating telomerase activity. Degradation of the key tumour suppression proteins leads to cell cycle deregulation and cellular immortalization, thus kickstarting the process of carcinogenesis. The level of E6 and E7 expression of high-risk HPV types increases as the grade of cervical intraepithelial neoplasia worsens. Since these changes in HPV mRNA expression of E6/E7 oncoproteins directly underlie the neoplastic phenotype (i.e. HPV mRNA tests correlate with actual virus replication, which is further down the HPV pathway towards development of pre-cancer changes), detection of HPV E6/E7 mRNA of these two oncoproteins could be more specific than detection of the HPV viral DNA.
Most HPV DNA tests target the 13–14 most oncogenic HPV types, whereas the HPV mRNA tests vary. At present there is only one technology commercially available and widely documented in the literature, called the Aptima™ mRNA assay, that can qualitatively detect the expression of HPV E6 and E7 mRNA from all 14 high-risk types of HPV (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) through real-time amplification. This system can carry out up to 250 tests in approximately five hours. There are two other assays that target fewer oncogenic types, but information and use remains limited at this time.
HPV mRNA testing is based on pooled detection of HPV E6/E7 mRNA from high-risk types of HPV. The test is considered positive if HPV E6/E7 mRNA is above the detection threshold for any individual type or for multiple types. The Aptima™ mRNA assay does not separate out or give information on individual genotypes, such as HPV16/18/45. However, a separate assay is available that can be used to detect HPV16/18/45 among women testing positive on the pooled assay. It includes an internal control that monitors the presence of nucleic acid, and its processing and amplification. A result is considered negative when HPV mRNA in a sample is below the detection threshold and the internal control is positive. A result is considered positive when HPV mRNA in a sample is above the detection threshold, independent of the internal control result. Results are considered invalid when both HPV mRNA and the internal control are below the detection limit (10).
1.3. Phased approach for development of updated recommendations and purpose of this guideline
Following the 2020 launch of the Global Strategy to accelerate the elimination of cervical cancer as a public health problem, a large panel of experts met to define the key areas of focus to increase access to screening and treatment to reach the 2030 targets. One of the agreed areas of focus was to update the existing 2013 WHO guidelines for screening and treatment of precancerous lesions for cervical cancer prevention (11), and to simplify the algorithms.
Guideline objective:
To improve national strategies for screening and treatment to prevent cervical cancer in all women, including women living with HIV.
It was decided that WHO’s updated cervical cancer screening and treatment guidance would be developed in four phases:
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| Phase 1 | Updated recommendations on screening and treatment and the clinical algorithms for the most commonly used primary screening tests and triage strategies (HPV DNA tests, cytology and VIA) for both women in general (i.e. women who are presumed or confirmed to be HIV-negative) and those living with HIV. Phase 1 also addresses routine screening programmes, the ages at which to initiate and stop screening, and the frequency of screening. |
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| Phase 2 | Evaluate the evidence and develop recommendations for the clinical algorithms using (a) HPV mRNA tests and (b) dual-stain cytology for the general population of women and for women living with HIV. |
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| Phase 3 | Develop recommendations for the implementation of these screening and treatment strategies. |
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| Phase 4 | Establish a consolidated “living guideline” for screening and treatment tests and algorithms (combining all the output from Phases 1–3), which will allow the recommendations to be updated as new evidence becomes available and is evaluated. |
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The output of Phase 1 was a guideline that was published and launched in July 2021, presenting a large set of recommendations and good practice statements, with a primary focus on the use of HPV DNA tests. For the rationale for the development of the new edition of recommendations for screening and treatment to prevent cervical cancer, please refer to section 1.3 of that guideline (12).
Since the HPV mRNA test is in clinical use as a recognized option for HPV nucleic acid amplification testing (NAAT), the GDG prioritized evaluating the evidence on HPV mRNA testing to make recommendations for its use. The objective in this phase of the guideline update was therefore to develop recommendations for the use of HPV mRNA detection as a primary screening test for cervical cancer prevention – both in the general population of women and in women living with HIV. In addition to evidence gathered for this update process, this guideline is also supported by evidence compiled in the IARC handbooks of cancer prevention: cervical cancer screening, Vol. 18, which considers HPV mRNA as a NAAT that can be used for cervical cancer screening (13, 14).
The clinical flowcharts for the algorithms presented in this guideline include HPV mRNA-based screening strategies and follow-up testing at 12 months post-treatment (see Annex 4). In the near future, the recommendations in this guideline will be integrated with the recommendations recently published in WHO guideline for screening and treatment of cervical pre-cancer lesions for cervical cancer prevention, second edition (12), along with the outputs of the upcoming phase on dual-stain cytology screening and the forthcoming recommendations on implementation of screening and treatment strategies, to develop a full consolidated version of this guidance.
1.4. Previous and existing WHO recommendations for screening and treatment to prevent cervical cancer and definitions
In 2006, WHO published Comprehensive cervical cancer control: a guide to essential practice (C4GEP), which was updated in a second edition in 2014 (15), consolidating all the recommendations for screening and treatment to prevent and treat cervical cancer up to that year. The consolidated C4GEP included the WHO recommendations for HPV vaccination, treatment of cervical cancer and pre-cancer lesions, and palliative care, as well as the recommendations from the previous edition (2013) of this guideline: WHO guidelines for screening and treatment of precancerous lesions for cervical cancer prevention (11). In 2019, WHO published guidance on the use of thermal ablation for treatment of cervical pre-cancer lesions (16), and in 2020, WHO published guidance documents to support the introduction and scale-up of screening and treatment interventions, specifically relating to HPV testing and relevant medical devices (17).
In the updated second edition of the recommendations on screening and treatment for cervical cancer prevention, two populations of women are referred to: women living with HIV and the general population of women, which refers to women who are presumed or confirmed HIV-negative, but whose HIV status may be unknown. In addition, two approaches to screening and treatment are distinguished, the “screen-and-treat approach” and the “screen, triage and treat approach”.
Screening and treatment approaches
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In the “screen-and-treat approach”, the decision to treat is based on a positive primary screening test only. 
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In the “screen, triage and treat approach”, the decision to treat is based on a positive primary screening test followed by a positive second test (a “triage” test), with or without histologically confirmed diagnosis. 
In a screen-and-treat approach, treatment is provided based on a positive primary screening test alone, without triage (i.e. no second screening test and no histopathological diagnosis).
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When the patient is eligible for ablative treatment, this should ideally be done immediately, at the same visit as the screening test (the single-visit approach). At some facilities, this is not feasible and a second visit is needed (the multiple-visit approach).
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Women who are not eligible for ablation can have excisional treatment on the same day if the clinic has the capacity for large-loop excision of the transformation zone (LLETZ).3 If LLETZ is not available on-site, women need to be referred for the excisional treatment or for further evaluation.
In a screen, triage and treat approach, the triage test is done if the primary screening test is positive, and the decision to treat is made when both the primary test and the triage test are positive.
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A positive triage test can lead to colposcopy with biopsy and histopathological examination for diagnosis to determine the appropriate treatment. The implementation of colposcopy and biopsy can be challenging, however, so this guideline also considers triage strategies that are not dependent on the availability of colposcopy.
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When the primary screening test is positive, and the triage test is negative, women need appropriate follow-up evaluation at a specified date according to the recommendations.
The publication of the output of Phase 1 of the update of the recommendations for screening and treatment to prevent cervical cancer (in July 2021) presented 23 recommendations and 7 good practice statements (12). Those recommendations focused mainly on the use of HPV DNA testing as the primary screening test. provides a summary of the recommendations.
Summary recommendations from the WHO guideline for screening and treatment of cervical pre-cancer lesions for cervical cancer prevention, second edition: HPV DNA tests.
The full set of recommendations is provided in the 2021 publication, WHO guideline for screening and treatment of cervical pre-cancer lesions for cervical cancer prevention, second edition (12), and also in Annex 5 of this guideline.
1.5. Target audience
This document is intended primarily for policy-makers, programme managers, programme officers and other professionals in the health sector who have responsibility for choosing strategies for cervical cancer prevention, at country, regional and district levels. Health-care professionals – such as doctors, nurses and community health workers working in reproductive health programmes, antenatal and postnatal services, family planning services, HIV/AIDS control programmes and in clinics that care for women at the district and primary health care levels – may also consult this document to understand how recommendations are developed and why it is vitally important to select and implement evidence-based strategies to prevent cervical cancer.
This document will also be informative in an adapted form for women, girls and their families in making decisions about cervical cancer screening and treatment.
All individuals have the right to equality and non-discrimination in sexual and reproductive health care. In this guideline, we recognize that most of the available evidence on cervical cancer is based on study populations of cisgender women, and we also recognize that cisgender women, transgender men, non-binary, gender fluid and intersex individuals born with a female reproductive system require cervical cancer prevention services. However, to be concise and facilitate readability, we use the term “women” to refer to all gender diverse people at risk for cervical cancer. Sexual and reproductive health service providers and cervical cancer prevention services must consider the needs of – and provide equal care to – all individuals independently of gender identity or its expression.
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In this guideline, “an HPV DNA test” refers to a high-risk HPV DNA test, and “an HPV mRNA test” refers to an HPV E6/E7 messenger RNA test. Both of these tests are nucleic acid amplification tests (NAATs).
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In this guideline, the term LLETZ is used to refer to excision of the transformation zone. In some countries, the term LEEP (loop electrosurgical excision procedure) is used, and the two terms are often used interchangeably.
