Home-based self-sampling vs clinician sampling for anal precancer screening: The Prevent Anal Cancer Self-Swab Study

Engagement and Factors Associated With Annual Anal Human Papillomavirus Screening Among Sexual and Gender Minority Individuals

BACKGROUND

Although self-sampling could help address anal cancer screening barriers, no studies have investigated annual engagement with this method or compared it with annual screening with a provider. Building on our baseline article, we compared annual anal screening engagement between home-based self-sampling and clinic-based clinician sampling.

METHODS

The Prevent Anal Cancer Self-Swab Study recruited and randomized sexual and gender minority individuals 25 years and older who have sex with men to a home or clinic arm. Home-based participants were mailed an anal human papillomavirus self-sampling kit at baseline and 12 months, whereas clinic-based participants were asked to schedule and attend 1 of 5 participating clinics at baseline and 12 months. Using Poisson regression, we conducted an intention-to-treat analysis of 240 randomized participants who were invited to screen at both timepoints.

RESULTS

More than half (58.8%) of participants completed annual (median = 370 days) anal screening. In the home arm, 65.0% of participants engaged in annual screening compared with 52.5% of clinic-based participants ( P = 0.049). When stratified by HIV status, persons living with HIV had a higher proportion of home (71.1%) versus clinic (22.2%) annual screening ( P < 0.001). Non-Hispanic Black participants participated more in home-based annual anal screening (73.1%) than annual clinic screening (31.6%; P = 0.01). Overall, annual screening engagement was significantly higher among participants who had heard of anal cancer from an LGBTQ organization, reported "some" prior anal cancer knowledge, preferred an insertive anal sex position, and reported any prior cancer diagnosis.

CONCLUSIONS

Annual screening engagement among those at disproportionate anal cancer risk was higher in the home arm.

Future Research Directions in Anal Cancer

While anal cancer is somewhat rare, it is increasing in incidence despite improving screening and the human papillomavirus vaccine. Given this, there is growing research into the management of high-grade squamous intraepithelial lesion as well as how to optimize screening approaches. This includes increased study of biomarkers to improve screening sensitivity as well as strategies to improve access and reduce loss to follow-up. Additionally, there is an ongoing research into the role of the microbiome in oncogenesis and research to adapt other treatments to anal cancer.

Self-collected versus clinician-collected anal swabs for anal cancer screening: A systematic review and meta-analysis

Anal squamous cell carcinoma (ASCC) incidence is increasing globally. International consensus guidelines published in 2024 include HPV and/or cytology testing of anal swabs in those at greatest risk of ASCC. Self-collected anal swabs may be important for increasing screening uptake, but evidence is needed as to their equivalence to clinician-collected swabs. We searched Medline, Embase, Cochrane Library, and CINAHL databases for publications to 13 June 2023. Studies were included if reporting data on HPV testing, cytology testing, or acceptability, for both self- and clinician-collected anal swabs. Risk of bias was assessed using the QUADAS-2 assessment tool. The primary outcome was HPV and cytology sampling adequacy. Secondary outcomes were HPV and cytology results, and acceptability of collection methods. Thirteen papers describing 10 studies were eligible. Sample adequacy was comparable between self- and clinician-collected swabs for HPV testing (meta-adequacy ratio: 1.01 [95% CI 0.97-1.05]) but slightly lower for cytology by self-collection (meta-adequacy ratio: 0.91 [95% CI 0.88-0.95]). There was no significant difference in prevalence (meta-prevalence ratio: 0.83 (95% CI 0.65-1.07) for any HR-HPV, 0.98 (95% CI 0.84-1.14) for any HPV, and 0.68 (95% CI 0.33-1.37) for HPV16), or any cytological abnormality (meta-prevalence ratio 1.01 [95% CI 0.86-1.18]). Only three papers reported acceptability results. Findings indicate self-collection gives equivalent sample adequacy for HPV testing and ~ 10% inferior adequacy for cytological testing. Meta-prevalence was similar for HPV and cytology, but confidence intervals were wide. Larger studies are required to definitively assess use of self-collected swabs in anal cancer screening programs, including acceptability.

Access Barriers in Testing for Sexually Transmitted Infections across Gender and Sexual Identities

Sexually transmitted infections (STIs) are steadily increasing in incidence. Marginalized communities across social categories (race, ethnicity, gender, and sexuality) face the heaviest burden, including Black, indigenous, Latino, queer (gay, bisexual), transgender, and nonbinary populations. These disparities persist even when controlled for high-risk sexual behaviors. The laboratory maintains a responsibility to develop and offer appropriate testing for all communities. This review aims to integrate the clinical laboratory's role in building sexual health testing options across genders and sexual behaviors with a focus on molecular, swab-based testing.

Identifying Motivators, Facilitators, and Barriers to Engagement and Retention in Anal Cancer Screening Among Men and Women with HIV in One Ryan White HIV/AIDS Clinic

Anal squamous cell carcinoma disproportionally affects people with HIV (PWH); however, engagement in anal cancer screening is low in many settings. This study was conducted to assess knowledge and perceptions of anal cancer screening to identify factors in the engagement and retention in prevention services among PWH. Semistructured interviews were conducted among adult PWH eligible for anal cancer screening in our Ryan White HIV/AIDS Program clinic. Descriptive statistics were tabulated; thematic analyses were performed to identify emerging motivators, facilitators, and barriers. Among 26 PWH, 9 had not been screened, 8 had undergone Papanicolaou (Pap) testing alone, and 9 had undergone anoscopy. The median age of the cohort was 55.2 years; 54% identified as men who have sex with men, and 54% identified as Black. In the unscreened cohort, participants were motivated by investing in their health and positive attitudes toward cancer prevention however were deterred by a lack of referral and low awareness about screening. Among those who had Pap testing, trust in healthcare providers and abnormal testing results were motivators to engagement, whereas lack of perceived risk of anal cancer and worry about pain of an anoscopy were prominent barriers. Among those who had anoscopy, perceived risk, positive experience with the procedure, and use of anxiolytics prior to anoscopy were motivators, whereas anxiety around a new cancer diagnosis and negative experience with anoscopy were barriers. Clinics seeking to build or strengthen their anal cancer screening programs can address the barriers described in this study to promote access to anal cancer screening among PWH.

Screening of Anal HPV Precancerous Lesions: A Review after Last Recommendations

Over the last decades, the incidence of anal cancer has increased worldwide. The discovery of the HPV virus as its primary cause and the natural progression of the disease, involving precancerous lesions, have resulted in significant interest in screening for anal cancer. The use of cytology testing, high-risk HPV DNA research, high-resolution anoscopy, and their combination has been adopted with variable success in detecting anal HPV precancerous lesions. Various studies have been carried out to evaluate the sensitivity and specificity of these techniques in different populations. High-risk populations for developing anal cancer have been identified through study of incidence and prevalence. Therefore, different scientific societies and experts worldwide have provided different recommendations for screening, but a universal approach has not yet been established. The inhomogeneity of different risk groups, the variable accessibility to specifical techniques, and the lack of data regarding the cost-benefit ratio of screening are the main problems to address in order to define a consensus guideline acceptable worldwide. The purpose of this paper is to provide a comprehensive review of the literature on HPV precancerous lesions and its screening, particularly after the release of recent recommendations.

Prevalence and risk factors for HPV seropositivity and anogenital DNA positivity among men who have sex with men: a repeated cross-sectional study

OBJECTIVES

This study aimed to assess associations of potential risk factors with human papillomavirus (HPV) seropositivity among men who have sex with men (MSM) and compare these to risk factors for anal and penile (HPV) deoxyribonucleic acid (DNA)-positivity in the same study population.

METHODS

Seropositivity and anal and penile HPV DNA-positivity were determined for seven high-risk HPV genotypes for MSM aged 16-24 years participating in Papillomavirus Surveillance among STI clinic Youngsters in the Netherlands (PASSYON) 2009-2021. Logistic regression models were conducted to assess risk factors for seropositivity, anal and penile HPV DNA-positivity.

RESULTS

Overall, 1019 MSM were included. HPV-16 and -18 were most common for serology, and anal and penile HPV DNA-positivity. Although no clear similarities were observed for most risk factors for HPV seropositivity and anal or penile DNA positivity, receptive anal intercourse (RAI) was the strongest associated risk factor for both seropositivity ('RAI ever' adjusted odds ratio [aOR] 3.50, 95% confidence interval [CI] 1.56-7.88; 'RAI previous 6 months' aOR 2.17, 95% CI 1.44-3.26) and anal DNA-positivity ('RAI previous 6 months' aOR 1.67, 95% CI 1.09-2.56).

CONCLUSIONS

Our study is suggestive of site-specific immune response after HPV infection; RAI might lead to anal HPV infections and consequently to seroconversion. Finally, as the two genotypes that are most oncogenic and preventable by all HPV vaccines were most common, our results underline the importance of gender-neutral vaccination.

Rationale and design of the Self-TI Study protocol: a cross-sectional human papillomavirus self-testing pilot study among transgender adults in England

INTRODUCTION

Persistent infection with high-risk human papillomavirus (HPV) is the causal agent of several cancers including cervical, anal and oropharyngeal cancer. Transgender men and transmasculine non-binary (TMNB) people with a cervix are much less likely to undergo cervical cancer screening than cisgender women. Transgender women and transfeminine non-binary (TWNB) people assigned male at birth may be at increased risk of HPV. Both TMNB and TWNB people face many barriers to HPV testing including medical mistrust due to stigma and discrimination.

METHODS AND ANALYSIS

The Self-TI Study (Self-TI) is a pilot study designed to measure acceptability and feasibility of HPV self-testing among transgender and non-binary people in England. TMNB people aged 25-65 years, with at least 1 year of testosterone, and TWNB people, aged 18 years and over, are eligible to participate. Participants self-collect up to four samples: an oral rinse, a first void urine sample, a vaginal swab (if applicable) and an anal swab. TMNB participants are asked to have an additional clinician-collected cervical swab taken following their routine Cervical Screening Programme sample. TWNB people are asked to take a self-collection kit to perform additional self-collection at home and mail the samples back to the clinic. Acceptability is assessed by a self-administered online survey and feasibility is measured as the proportion of samples returned in the clinic and from home.

ETHICS AND DISSEMINATION

Self-TI received ethical approval from the Research Ethics Committee of Wales 4 and ethical review panel within the Division of Cancer Epidemiology and Genetics at the US National Cancer Institute. Self-TI was coproduced by members of the transgender and non-binary community, who served as authors, collaborators and members of the patient and public involvement (PPI) group. Results of this study will be shared with the community prior to being published in peer-reviewed journals and the PPI group will help to design the results dissemination strategy. The evidence generated from this pilot study could be used to inform a larger, international study of HPV self-testing in the transgender and non-binary community.

TRIAL REGISTRATION NUMBER

NCT05883111.

Engagement and factors associated with annual anal human papillomavirus screening among sexual and gender minority individuals

Objectives

Annual screening with a provider has been recommended for groups at highest risk for anal cancer. Anal self-sampling could help address screening barriers, yet no studies have examined annual engagement with this method.

Methods

The Prevent Anal Cancer Self-Swab Study recruited sexual and gender minority individuals 25 years and over who have sex with men in Milwaukee, Wisconsin to participate in an anal cancer screening study. Participants were randomized to a home or clinic arm. Home-based participants were mailed an anal human papillomavirus self-sampling kit at baseline and 12 months, while clinic-based participants were asked to schedule and attend one of five participating clinics at baseline and 12 months. Using Poisson regression, we conducted an intention-to-treat analysis of 240 randomized participants who were invited to screen at both timepoints.

Results

58.8% of participants completed annual (median=370 days) anal screening. When stratified by HIV status, persons living with HIV had a higher proportion of home (71.1%) versus clinic (22.2%) annual screening ( p <0.001). Non-Hispanic Black participants had a higher proportion of home-based annual anal screening engagement (73.1%) compared to annual clinic screening engagement (31.6%) ( p =0.01). Overall, annual screening engagement was significantly higher among participants who had heard of anal cancer from an LGBTQ organization, reported "some" prior anal cancer knowledge, preferred an insertive anal sex position, and reported a prior cancer diagnosis. Annual screening engagement was significantly lower for participants reporting a medical condition.

Conclusions

Annual screening engagement among those at disproportionate anal cancer risk was higher in the home arm.

The influence of home versus clinic anal human papillomavirus sampling on high-resolution anoscopy uptake in the Prevent Anal Cancer Self-Swab Study

Background Anal cancer disproportionately affects sexual and gender minority individuals living with HIV. High-resolution anoscopy (HRA) is an in-clinic procedure to detect precancerous anal lesions and cancer, yet prospective data on factors associated with HRA attendance are lacking. We examined whether anal HPV sampling at home versus in a clinic impacts HRA uptake and assessed HRA acceptability. Methods Sexual and gender minority individuals were randomised to home-based self-sampling or clinical sampling. All were asked to attend in-clinic HRA 1year later. We regressed HRA attendance on study arm using multivariable Poisson regression and assessed HRA acceptability using χ 2 tests. Results A total of 62.8% of 196 participants who engaged in screening attended HRA. Although not significant (P =0.13), a higher proportion of participants who engaged in clinic-based screening attended HRA (68.5%) compared to home-based participants (57.9%). Overall, HRA uptake was higher among participants with anal cytology history (aRR 1.40, 95% CI 1.07-1.82), and lower among participants preferring a versatile anal sex position versus insertive (aRR 0.70, 95% CI 0.53-0.91), but did not differ by race or HIV serostatus. In the clinic arm, persons living with HIV had lower HRA attendance (42.9%) versus HIV-negative participants (73.3%) (P =0.02) and Black non-Hispanic participants had lower HRA attendance (41.7%) than White non-Hispanic participants (73.1%), (P =0.04). No differences in attendance by race or HIV status were observed in the home arm. Conclusions HRA uptake differed significantly by race and HIV status in the clinic arm but not the home arm.

Concordance of Human Papillomavirus Genotypes in Mailed Home-Based Self-Collected Versus Clinician-Collected Anal Swabs Among Sexual and Gender Minority Individuals

BACKGROUND

Home-based self-sampling may be a viable option for anal cancer screening among sexual minority men (SMM). Yet limited research has compared home-based self-collected with clinician-collected anal swabs for human papillomavirus (HPV) genotyping.

METHODS

The Prevent Anal Cancer Self-Swab Study recruited SMM and transgender persons 25 years and over in Milwaukee, WI to participate in an anal cancer screening study. Participants were randomized to a home or clinic arm. Home-based participants were mailed an anal self-sampling kit to complete and return via postal mail. They were also asked to attend a clinic appointment where a clinician collected an anal swab. Swabs were HPV-genotyped using the SPF 10 -LiPA 25 assay. We analyzed 79 paired self and clinician swabs to determine HPV prevalence, percent agreement, and sensitivity and specificity of the mailed home-based anal self-swab to detect HPV genotypes using the clinician-collected swab as the reference.

RESULTS

The median number of days between the home and clinic swab was 19 days (range = 2 to 70). Human papillomavirus was detected in 73.3% of self and 75.0% of clinician anal swabs ( P = 0.99). Prevalence of any HPV, any high-risk HPV, any low-risk HPV, and individual HPV types did not significantly differ between self and clinician anal swabs. Agreement between self and clinician swabs was over 90% for 21 of the 25 HPV genotypes. Mailed home-based self-collected swabs had a sensitivity of 94.1% (95% confidence interval, 82.9-99.0) for detection of high-risk HPV versus clinician-collected sampling.

CONCLUSIONS

Mailed home-based self-collected and clinician-collected anal swabs demonstrated high concordance for HPV genotyping.

A comprehensive review of anal cancer-with a special focus on anal cytology

The diagnosis of anal cancer is relatively uncommon, but its incidence has been steadily increasing in high-risk populations. In the 2001 Bethesda System for Reporting Cervical Cytology, anal cytology was introduced as a component. Since then, it has been recognized as a potential tool for screening anal cancer, often in conjunction with high-resolution anoscopy. There are notable similarities between anal cancer and cervical cancer, including the causative role of human papillomavirus. However, there are also significant differences, particularly in terms of disease prevalence. Anal cytology may be used as a primary screening test, and in the event of abnormalities, patients are subsequently directed for high-resolution anoscopy. However, the best approach for anal cancer screening is yet to be determined and uniformly implemented. This comprehensive review article provides an in-depth analysis of the epidemiology and incidence of anal precursor and malignant lesions. It explores the various methods of sample procurement, preparation, interpretation (including sensitivity and specificity), and reporting terminology in anal cytology. The article also addresses the significance of concurrent high-risk human papillomavirus screening in anal cytology and its role in screening programs. Furthermore, it discusses the follow-up, prevention, and subsequent management strategies for anal cancers. By synthesizing current knowledge in these areas, this review aims to provide a comprehensive understanding of anal cytology and its implications in the early detection, prevention, and management of anal neoplasia and cancer.

Acceptability of Anal Human Papillomavirus Home Self-Sampling and Clinician Sampling Among Sexual and Gender Minority Individuals in Milwaukee, Wisconsin: The Prevent Anal Cancer Self-Swab Study

Purpose: Anal cancer has disproportionately high incidence among sexual minority men. We compared acceptability of home versus clinic human papillomavirus (HPV) anal swabbing. Methods: The Prevent Anal Cancer Self-Swab Study recruited sexual and gender minority individuals in Milwaukee, Wisconsin. Eligible participants were randomized to a home or clinic arm. Home participants received a mailed anal HPV self-sampling kit. Clinic participants attended a clinic appointment where a clinician collected an anal HPV swab. We examined acceptability (overall thoughts, comfort with method, pain, and future willingness to swab) of home versus clinic swabbing using postswab survey responses. Results: A total of 191 individuals completed swabbing and a postswab survey (home = 53.4%, clinic = 46.6%). Mean age was 47 years (range = 25-78). Reported overall thoughts about home (71.6%) and clinic (69.7%) swabbing were mostly positive (p = 0.83). Overall thoughts about the home kit did not differ by participant characteristics, but overall thoughts about clinician swabbing differed by race (p = 0.04) and HIV status (p = 0.002). Nearly all participants (98.4%) reported they were comfortable receiving the kit or getting the swabbing in the clinic, reported little or no pain (98.4%), and reported willingness to undergo swabbing in the future (97.9%). After swabbing, clinic participants reported greater trust that swabbing can give accurate information about anal cancer risk (89.9%) than home participants (69.6%) (p < 0.001), and that swabbing will help them avoid anal cancer (clinic = 79.8%, home = 59.8%) (p = 0.01). Conclusion: Anal swabbing acceptability was high and did not differ between home and clinic. Participants reported high confidence and knowledge using the mailed anal self-sampling kit. Clinical Trial Registration number is NCT03489707.

The influence of home versus clinic anal human papillomavirus sampling on high-resolution anoscopy uptake in the Prevent Anal Cancer Self-Swab Study

Background

Anal cancer disproportionately affects men who have sex with men (MSM) living with HIV. High-resolution anoscopy (HRA) is an in-clinic procedure to detect precancerous anal lesions and cancer, yet prospective data on factors associated with HRA attendance are lacking. We examined whether anal HPV sampling at home versus in a clinic impacts HRA uptake and assessed HRA acceptability.

Method

MSM and trans persons 25 years and older were randomized to home-based self-sampling or clinical sampling. All were asked to attend in-clinic HRA one year later. We regressed HRA attendance on study arm using multivariable Poisson regression and assessed HRA acceptability using χ 2 tests.

Results

62.8% of 196 participants who engaged in screening attended HRA. Although not significant ( p =0.13), a higher proportion of participants who engaged in clinic-based screening attended HRA (68.5%) compared to home-based participants (57.9%). Overall, HRA uptake was higher among participants with anal cytology history (aRR 1.44, 95% CI 1.11 - 1.87) and lower among participants preferring versatile anal sex position versus insertive (aRR 0.70, 95% CI 0.53 - 0.91), but did not differ by race or HIV serostatus. In the clinic arm, persons living with HIV had lower HRA attendance (42.9%) versus HIV-negative participants (73.3%) ( p =0.02) and Black non-Hispanic participants had lower HRA attendance (41.7%) than White non-Hispanic participants (73.1%), ( p =0.04); however, no differences in attendance by race or HIV status were observed in the home arm.

Conclusions

HRA uptake differed significantly by race and HIV status in the clinic arm but not the home arm.