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BMJ (Clinical Research Ed.) Aug 2022To explore the efficacy of human papillomavirus (HPV) vaccination on the risk of HPV infection and recurrent diseases related to HPV infection in individuals undergoing... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To explore the efficacy of human papillomavirus (HPV) vaccination on the risk of HPV infection and recurrent diseases related to HPV infection in individuals undergoing local surgical treatment.
DESIGN
Systematic review and meta-analysis DATA SOURCES: PubMed (Medline), Scopus, Cochrane, Web of Science, and ClinicalTrials.gov were screened from inception to 31 March 2021.
REVIEW METHODS
Studies reporting on the risk of HPV infection and recurrence of disease related to HPV infection after local surgical treatment of preinvasive genital disease in individuals who were vaccinated were included. The primary outcome measure was risk of recurrence of cervical intraepithelial neoplasia grade 2 or higher (CIN2+) after local surgical treatment, with follow-up as reported by individual studies. Secondary outcome measures were risk of HPV infection or other lesions related to HPV infection. Independent and in duplicate data extraction and quality assessment were performed with ROBINS-I and RoB-2 tools for observational studies and randomised controlled trials, respectively. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was implemented for the primary outcome. Observational studies and randomised controlled trials were analysed separately from post hoc analyses of randomised controlled trials. Pooled risk ratios and 95% confidence intervals were calculated with a random effects meta-analysis model. The restricted maximum likelihood was used as an estimator for heterogeneity, and the Hartung-Knapp-Sidik-Jonkman method was used to derive confidence intervals.
RESULTS
22 articles met the inclusion criteria of the review; 18 of these studies also reported data from a non-vaccinated group and were included in the meta-analyses (12 observational studies, two randomised controlled trials, and four post hoc analyses of randomised controlled trials). The risk of recurrence of CIN2+ was reduced in individuals who were vaccinated compared with those who were not vaccinated (11 studies, 19 909 participants; risk ratio 0.43, 95% confidence interval 0.30 to 0.60; I=58%, τ=0.14, median follow-up 36 months, interquartile range 24-43.5). The effect estimate was even stronger when the risk of recurrence of CIN2+ was assessed for disease related to HPV subtypes HPV16 or HPV18 (six studies, 1879 participants; risk ratio 0.26, 95% confidence interval 0.16 to 0.43; I=0%, τ=0). Confidence in the meta-analysis for CIN2+ overall and CIN2+ related to HPV16 or HPV18, assessed by GRADE, ranged from very low to moderate, probably because of publication bias and inconsistency in the studies included in the meta-analysis. The risk of recurrence of CIN3 was also reduced in patients who were vaccinated but uncertainty was large (three studies, 17 757 participants; 0.28, 0.01 to 6.37; I=71%, τ=1.23). Evidence of benefit was lacking for recurrence of vulvar, vaginal, and anal intraepithelial neoplasia, genital warts, and persistent and incident HPV infections, although the number of studies and participants in each outcome was low.
CONCLUSION
HPV vaccination might reduce the risk of recurrence of CIN, in particular when related to HPV16 or HPV18, in women treated with local excision. GRADE assessment for the quality of evidence indicated that the data were inconclusive. Large scale, high quality randomised controlled trials are required to establish the level of effectiveness and cost of HPV vaccination in women undergoing treatment for diseases related to HPV infection.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42021237350.
Topics: Alphapapillomavirus; Female; Human papillomavirus 16; Humans; Papillomaviridae; Papillomavirus Infections; Papillomavirus Vaccines; Uterine Cervical Neoplasms; Vaccination; Uterine Cervical Dysplasia
PubMed: 35922074
DOI: 10.1136/bmj-2022-070135 -
The Lancet. Oncology Apr 2023Human papillomavirus (HPV) DNA and p16 positivity have crucial roles in the pathogenesis of vulvar cancer and vulvar intraepithelial neoplasia. We aimed to examine the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Human papillomavirus (HPV) DNA and p16 positivity have crucial roles in the pathogenesis of vulvar cancer and vulvar intraepithelial neoplasia. We aimed to examine the pooled prevalence of HPV DNA and p16 positivity in vulvar cancer and vulvar intraepithelial neoplasia worldwide.
METHODS
In this systematic review and meta-analysis, we searched PubMed, Embase, and the Cochrane Library databases for studies published between Jan 1, 1986, and May 6, 2022, that reported the prevalence of HPV DNA, or p16 positivity, or both, in histologically verified vulvar cancer or vulvar intraepithelial neoplasia. Studies on a minimum of five cases were included. Study-level data were extracted from the published studies. Random effect models were used to examine the pooled prevalence of HPV DNA and p16 positivity in both vulvar cancer and vulvar intraepithelial neoplasia, which were further investigated using stratified analyses by histological subtype, geographical region, HPV DNA or p16 detection method, tissue sample type, HPV genotype, publication year, and age at diagnosis. Additionally, meta-regression was applied to explore sources of heterogeneity.
FINDINGS
We retrieved 6393 search results, of which 6233 were excluded for being duplicates or after application of our inclusion and exclusion criteria. We also identified two studies from manual searches of references lists. 162 studies were eligible for inclusion in the systematic review and meta-analysis. The prevalence of HPV in vulvar cancer (91 studies; n=8200) was 39·1% (95% CI 35·3-42·9) and in vulvar intraepithelial neoplasia (60 studies; n=3140) was 76·1% (70·7-81·1). The most predominant HPV genotype in vulvar cancer was HPV16 (78·1% [95% CI 73·5-82·3]), followed by HPV33 (7·5% [4·9-10·7]). Similarly, HPV16 (80·8% [95% CI 75·9-85·2]) and HPV33 (6·3% [3·9-9·2]) were also the most two predominant HPV genotypes in vulvar intraepithelial neoplasia. The distribution of type-specific HPV genotypes in vulvar cancer among geographical regions was different, with HPV16 varying between regions, showing a high prevalence in Oceania (89·0% [95% CI 67·6-99·5]) and a low prevalence in South America (54·3% [30·2-77·4]). The prevalence of p16 positivity in patients with vulvar cancer was 34·1% (95% CI 30·9-37·4; 52 studies; n=6352), and it was 65·7% (52·5-77·7; 23 studies; n=896) in patients with vulvar intraepithelial neoplasia. Furthermore, among patients with HPV-positive vulvar cancer, p16 positivity prevalence was 73·3% (95% CI 64·7-81·2), compared with 13·8% (10·0-18·1) in HPV-negative vulvar cancer. The prevalence of double positivity for HPV and p16 was 19·6% (95% CI 16·3-23·0) in vulvar cancer and 44·2% (26·3-62·8) in vulvar intraepithelial neoplasia. Most analyses had large heterogeneity (I>75%).
INTERPRETATION
The high prevalence of HPV16 and HPV33 in vulvar cancer and vulvar intraepithelial neoplasia emphasised the importance of nine-valent HPV vaccination in preventing vulvar neoplasm. Additionally, this study highlighted the potential clinical significance of double positivity for HPV DNA and p16 in vulvar neoplasm.
FUNDING
Taishan Scholar Youth Project of Shandong Province, China.
Topics: Female; Humans; Adolescent; Vulvar Neoplasms; Cyclin-Dependent Kinase Inhibitor p16; Human Papillomavirus Viruses; DNA, Viral; Prevalence; Papillomavirus Infections; Carcinoma in Situ; Carcinoma, Squamous Cell; Papillomaviridae; Human papillomavirus 16
PubMed: 36933562
DOI: 10.1016/S1470-2045(23)00066-9 -
Annals of Oncology : Official Journal... Feb 2020Although local treatments for cervical intraepithelial neoplasia (CIN) are highly effective, it has been reported that treated women remain at increased risk of cervical... (Meta-Analysis)
Meta-Analysis
Incidence and mortality from cervical cancer and other malignancies after treatment of cervical intraepithelial neoplasia: a systematic review and meta-analysis of the literature.
BACKGROUND
Although local treatments for cervical intraepithelial neoplasia (CIN) are highly effective, it has been reported that treated women remain at increased risk of cervical and other cancers. Our aim is to explore the risk of developing or dying from cervical cancer and other human papillomavirus (HPV)- and non-HPV-related malignancies after CIN treatment and infer its magnitude compared with the general population.
MATERIALS AND METHODS
Design: Systematic review and meta-analysis. Eligibility criteria: Studies with registry-based follow-up reporting cancer incidence or mortality after CIN treatment.
DATA SYNTHESIS
Summary effects were estimated using random-effects models.
OUTCOMES
Incidence rate of cervical cancer among women treated for CIN (per 100 000 woman-years). Relative risk (RR) of cervical cancer, other HPV-related anogenital tract cancer (vagina, vulva, anus), any cancer, and mortality, for women treated for CIN versus the general population.
RESULTS
Twenty-seven studies were eligible. The incidence rate for cervical cancer after CIN treatment was 39 per 100 000 woman-years (95% confidence interval 22-69). The RR of cervical cancer was elevated compared with the general population (3.30, 2.57-4.24; P < 0.001). The RR was higher for women more than 50 years old and remained elevated for at least 20 years after treatment. The RR of vaginal (10.84, 5.58-21.10; P < 0.001), vulvar (3.34, 2.39-4.67; P < 0.001), and anal cancer (5.11, 2.73-9.55; P < 0.001) was also higher. Mortality from cervical/vaginal cancer was elevated, but our estimate was more uncertain (RR 5.04, 0.69-36.94; P = 0.073).
CONCLUSIONS
Women treated for CIN have a considerably higher risk to be later diagnosed with cervical and other HPV-related cancers compared with the general population. The higher risk of cervical cancer lasts for at least 20 years after treatment and is higher for women more than 50 years of age. Prolonged follow-up beyond the last screening round may be warranted for previously treated women.
Topics: Alphapapillomavirus; Female; Humans; Incidence; Middle Aged; Papillomavirus Infections; Uterine Cervical Neoplasms; Uterine Cervical Dysplasia
PubMed: 31959338
DOI: 10.1016/j.annonc.2019.11.004 -
Cancers Mar 2023Vulvar Paget's disease (VPD) is a rare form of cutaneous adenocarcinoma of the vulva, which accounts for about 1-2% of all vulvar neoplasms and mainly affects... (Review)
Review
Vulvar Paget's disease (VPD) is a rare form of cutaneous adenocarcinoma of the vulva, which accounts for about 1-2% of all vulvar neoplasms and mainly affects post-menopausal women. The clinical presentation is usually non-specific and mimics chronic erythematous skin lesions; therefore, the diagnosis is often difficult and delayed. Although VPD is typically diagnosed at a locally advanced stage and has a high recurrence rate, the prognosis is overall favorable with a 5-year survival of nearly 90%. Due to the limited and poor-quality evidence, there is no global consensus on optimal management. Therefore, we performed a systematic review of the literature through the main electronic databases to deepen the current knowledge of this rare disease and discuss the available treatment strategies. Wide surgical excision is recommended as the standard-of-care treatment and should be tailored to the tumor position/extension and the patient's performance status. The goal is to completely remove the tumor and achieve clear margins, thus reducing the rate of local recurrences. Non-surgical treatments, such as radiotherapy, chemotherapy, and topical approaches, can be considered, especially in the case of unresectable and recurrent disease. In the absence of clear recommendations, the decision-making process should be individualized, also considering the new emerging molecular targets, such as HER2 and PD-L1, which might pave the way for future targeted therapies. The current review aims to raise awareness of this rare disease and encourage international collaboration to collect larger-scale, high-quality evidence and standardize treatment.
PubMed: 36980691
DOI: 10.3390/cancers15061803 -
Journal of Lower Genital Tract Disease Jan 2023Neoplasms arising from the vulva are uncommon and comprise various subtypes. Given the recent advancements in the molecular aspects of oncologic pathology and how they...
OBJECTIVES
Neoplasms arising from the vulva are uncommon and comprise various subtypes. Given the recent advancements in the molecular aspects of oncologic pathology and how they have impacted cancer treatment, an understanding of recent innovations in the molecular features of vulvar lesions is important.
MATERIALS AND METHODS
Systematic literature search was performed on PubMed, Google Scholar, and Scopus databases for molecular and genetic characteristics of vulvar neoplasms. Peer-reviewed literature published in English is included.
RESULTS
Squamous cell carcinoma (SCC) and its precursors are the predominant neoplasm at this site. Human papillomavirus (HPV) plays a crucial role in the pathogenesis of some of these lesions. Human papillomavirus-associated SCC follows the carcinogenic pathway driven by viral proteins E6 and E7 while HPV-independent SCC shows a high incidence of mutation of TP53 and CDKN2A genes. Mutations in the genes involving the PI3K-Akt pathway play an important role in the pathogenesis of both types of SCC. Among other vulvar malignancies, melanoma, and vulvar Paget disease (VPD) pose a significant clinical challenge and have unique molecular characteristics. Compared with dermal cutaneous melanoma, vulvar melanoma shows a higher rate of mutation of cKIT and NRAS genes and a lower rate of mutations in BRAF . Less than 20% of VPD shows amplification of ERBB2 and seldom shows mutation in genes involving the PI3K-Akt pathway.
CONCLUSIONS
Several potentially targetable molecular pathways have emerged as they have been shown to be involved in the tumorigenesis of SCC, melanoma, and VPD.
Topics: Female; Humans; Carcinoma, Squamous Cell; Human Papillomavirus Viruses; Melanoma; Papillomavirus Infections; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Skin Neoplasms; Vulvar Neoplasms
PubMed: 36083687
DOI: 10.1097/LGT.0000000000000701 -
Clinical Nuclear Medicine Feb 2021The aims of this study were to determine the role of 18F-FDG PET/CT in vulvar cancer patients and to extract summary estimates of its diagnostic performance for... (Meta-Analysis)
Meta-Analysis
AIM
The aims of this study were to determine the role of 18F-FDG PET/CT in vulvar cancer patients and to extract summary estimates of its diagnostic performance for preoperative lymph node staging.
PATIENTS AND METHODS
PubMed/Medline and Embase databases were searched to identify studies evaluating 18F-FDG PET/CT in vulvar cancer patients. The assessment of methodological quality of the included articles was performed. Per-patient and per-groin pooled estimates, with 95% confidence intervals (CIs), of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic odds ratio (DOR) were calculated.
RESULTS
Ten articles were included in the systematic review, 7 among which evaluated the diagnostic performance of preoperative 18F-FDG PET/CT for lymph node staging. Qualitative per-patient analysis (72 patients from 4 studies) resulted in estimated pooled sensitivity, specificity, PPV, NPV, and DOR of 0.70 (95% CI, 0.44-0.95), 0.90 (95% CI, 0.76-1.04), 0.86 (95% CI, 0.66-1.06), 0.77 (95% CI, 0.56-0.97), and 10.49 (95% CI, 1.68-65.50), respectively. Qualitative per-groin analysis (245 groins from 5 studies) resulted in estimated pooled sensitivity, specificity, PPV, NPV, and DOR of 0.76 (95% CI, 0.57-0.94), 0.88 (95% CI, 0.82-0.94), 0.70 (95% CI, 0.55-0.85), 0.92 (95% CI, 0.86-0.97), and 19.43 (95% CI, 6.40-58.95), respectively.
CONCLUSIONS
Despite limited literature data, this systematic review and meta-analysis revealed that a negative preoperative PET/CT scan may exclude groin metastases in at least early-stage vulvar cancer patients currently unfit for sentinel node biopsy and select those eligible for a less invasive surgical treatment. A positive PET/CT result should otherwise be interpreted with caution. Larger prospective studies are needed to confirm these results and to evaluate the diagnostic value of standardized semiquantitative analysis compared with the qualitative one.
Topics: Female; Fluorodeoxyglucose F18; Humans; Neoplasm Staging; Positron Emission Tomography Computed Tomography; Vulvar Neoplasms
PubMed: 33234921
DOI: 10.1097/RLU.0000000000003411 -
The interplay of HIV and human papillomavirus-related cancers in sub-Saharan Africa: scoping review.Systematic Reviews Apr 2020People living with HIV (PLHIV) are at a high risk of developing HPV-related cancers. HPV-related malignancies occur frequently and/or are high among PLHIV, with cervical... (Review)
Review
BACKGROUND
People living with HIV (PLHIV) are at a high risk of developing HPV-related cancers. HPV-related malignancies occur frequently and/or are high among PLHIV, with cervical cancer as a designated AIDS-defining condition. We aimed to explore the evidence on the interplay of HIV and HPV-related cancers in sub-Saharan Africa (SSA).
METHODS
The scoping review was guided by Arksey and O'Malley's framework. We searched for literature from the following databases: PubMed; World Health Organization (WHO) Library; Science Direct; Google Scholar and EBSCOhost (Academic search complete, Health Source: Nursing/Academic Edition, CINAHL). Studies reporting on evidence HIV and HPV-related cancers interplay in SSA were eligible for inclusion in this review. The Mixed Methods Appraisal Tool (MMAT) tool was used to assess the risk of bias of the included studies. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was used for reporting the search results. Thematic analysis used to reveal the emerging themes from the included studies.
RESULTS
A total of 74 potentially eligible articles were screened. Of these, nine (7 reviews, 1 transversal case controls, and 1 quantitative study) were eligible for data extraction. The studies reported about a total of 16,351 participants in different settings. The nine included studies showed evidence of cervical cancer among HIV-infected women and distribution of HPV infection and cervical abnormalities among HIV-positive individuals. In the four studies generalizing about HIV and anal cancer, only one reported about HPV. Two studies generally reported about HIV and head and neck cancers and one reported about interaction of HIV with vaginal cancer, vulvar cancer, and penile cancer, respectively.
CONCLUSION
HIV positivity is associated with increased prevalence of HPV infection on different anatomic sites, which will result in increased burden of HPV-related cancers among PLHIV. Furthermore, primary studies with robust study designs aimed at investigating the risk developing HPV-related cancers among PLHIV are recommended. Systematic review registration: PROSPERO CRD42017062403.
Topics: Africa South of the Sahara; Alphapapillomavirus; Female; HIV Infections; Humans; Neoplasms; Papillomaviridae; Papillomavirus Infections
PubMed: 32321580
DOI: 10.1186/s13643-020-01354-1 -
Journal of Lower Genital Tract Disease Apr 2022Vulvar intraepithelial neoplasia (VIN) is a premalignant condition with high recurrence rates despite treatment. Vulvar intraepithelial neoplasia develops through...
OBJECTIVE
Vulvar intraepithelial neoplasia (VIN) is a premalignant condition with high recurrence rates despite treatment. Vulvar intraepithelial neoplasia develops through separate etiologic pathways relative to the presence or absence of human papillomavirus (HPV) and TP53 mutations. This systematic review was conducted (1) to identify historical risk factors for the development, recurrence, and progression of VIN and (2) to critique these risk factors in the context of advances made in the stratification of VIN based on HPV or TP53 status.
MATERIALS AND METHODS
A systematic search was performed on MEDLINE, Embase, Cochrane Database, PsychInfo, and CINAHL from inception to July 5, 2021. Three gynecologic oncologists independently evaluated the eligibility of studies based on predetermined inclusion and exclusion criteria, abstracted data, and then analyzed the relevant data.
RESULTS
A total of 1,969 studies (involving 6,983 patients) were identified. Twenty-nine studies met inclusion criteria. The quality of evidence was low; primarily level 2b (Oxford Centre for Evidence-Based Medicine). Risk factors associated with the development of VIN include: smoking and coexisting vulvar dermatoses. Risk factors associated with recurrence include: smoking, multifocal disease, and positive surgical margins. Recent studies identified the presence of differentiated VIN/TP53 mutation as the most significant risk factor for both VIN recurrence and malignant progression.
CONCLUSIONS
The current body of evidence consists primarily of small retrospective observational studies. Well-designed retrospective case-control series and/or prospective observational studies are urgently needed. Ideally, future studies will collect standardized data regarding associated risk factors and stratify women with VIN based on HPV and TP53 status.
Topics: Carcinoma in Situ; Female; Humans; Observational Studies as Topic; Papillomaviridae; Papillomavirus Infections; Retrospective Studies; Risk Factors; Vulvar Neoplasms
PubMed: 35249976
DOI: 10.1097/LGT.0000000000000662 -
Gynecologic Oncology Mar 2023This multicenter study aimed to investigate the role of preoperative lymphatic mapping and sentinel node biopsy (SNB) as well as the impact of negative SNB on...
OBJECTIVE
This multicenter study aimed to investigate the role of preoperative lymphatic mapping and sentinel node biopsy (SNB) as well as the impact of negative SNB on loco-regional control and survival in vulvar melanoma patients with clinically negative nodes (cN0).
METHODS
Patients who had a proven vulvar melanoma with a Breslow thickness of 1-4 mm, cN0 and underwent a preoperative lymphatic mapping followed by SNB between July 2013 and March 2021 were retrospectively included. Groin recurrence and mortality rate were calculated as absolute and relative frequency. Disease-free survival (DFS) and overall survival (OS) were assessed by the Kaplan-Meier method. We provided a systematic review, searching among PubMed/Medline and Embase libraries. A total of 6 studies were identified (48 patients).
RESULTS
A total of 18 women were included. Preoperative planar images showed 51 SNs in 28 groins. Additional SPECT/CT images were acquired in 5/18 cases; SNs were identified pre- and intra-operatively in all cases. A total of 65 SNs were excised from 28 groins. A total of 13/18 (72.2%) patients (21/28 groins, 75%) had negative SNs with no groin recurrences and 12/13 (92.3%) were still alive at last follow-up. Five out of the 18 (27.8%) patients (7/28 groins, 25%) had positive SNs, 2/5 (40%) patients died of cancer after 26.2 and 33.8 months, respectively. The median DFS and OS for the entire cohort were 17.9 months (95% CI, 10.3-19.9) and 65.0 months (95% CI, 26.2-infinite), respectively. The probability of DFS and OS at 3 years were 15.5% (95% CI, 2.6-38.7) and 64.3% (95% CI, 15.5-90.2), respectively.
CONCLUSIONS
The use of preoperative lymphatic mapping followed by SNB permits a precise and minimally invasive surgical approach in cN0 vulvar melanoma patients. Negative SNB is associated with low risk of groin relapse and good survival.
Topics: Humans; Female; Lymphatic Metastasis; Retrospective Studies; Neoplasm Recurrence, Local; Sentinel Lymph Node Biopsy; Skin Neoplasms; Melanoma; Vulvar Neoplasms; Lymph Node Excision; Lymph Nodes; Multicenter Studies as Topic
PubMed: 36696819
DOI: 10.1016/j.ygyno.2023.01.011 -
International Journal of Gynecological... Mar 2022Appropriate diagnosis and treatment of gynecological cancers in people living with human immunodeficiency virus (HIV) remains a clinical challenge given rapid changes in... (Review)
Review
Appropriate diagnosis and treatment of gynecological cancers in people living with human immunodeficiency virus (HIV) remains a clinical challenge given rapid changes in both HIV and cancer management and a lack of prospective clinical trial data inclusive of the HIV population. A semi-systematic literature review was performed to identify published studies addressing risk factors, screening, treatment efficacy, treatment toxicity, and prognosis for people living with HIV diagnosed with gynecological malignancies, with a focus on radiotherapy and cervical cancer, given the relative paucity of literature on uterine, ovarian, and vulvovaginal cancers in people living with HIV. People living with HIV are more likely to be co-infected with human papilloma virus and more likely to develop human papilloma virus-associated malignancies. People living with HIV are less likely to receive cancer treatment compared with HIV-uninfected cancer patients, even after adjusting for differences in clinical features and sociodemographic variables. The literature on cervical cancer outcomes is mixed, with some studies demonstrating that people living with HIV have inferior treatment tolerability, response rates, and survival following chemoradiotherapy, and others showing no difference in these outcomes, particularly in patients receiving antiretroviral therapy. Importantly, even in the series showing inferior outcomes in people living with HIV, there were long-term survivors after administration of curative therapy. Consistent with published cancer management guidelines, people living with HIV diagnosed with gynecological cancers should be treated with standard cancer therapy. Co-management with the patient's HIV specialist is critical to avoid overlapping toxicities and provide optimal supportive care. The morbidity and mortality caused by gynecologic cancers in this population can be mitigated by early diagnosis, appropriate treatment delivery including inclusion of people with HIV in cancer clinical trials, and diligent HIV management.
Topics: Female; HIV; HIV Infections; Humans; Mass Screening; Risk Factors; Uterine Cervical Neoplasms
PubMed: 35256433
DOI: 10.1136/ijgc-2021-002533