Human Papillomavirus-Associated Anal Cancer Incidence and Burden Among US Men, According to Sexual Orientation, Human Immunodeficiency Virus Status, and Age

Health Disparities and Anal Cancer

Health disparities are preventable differences in health outcomes that are experienced by disadvantaged patient populations. Disparities in prevention, incidence, treatment, and mortality exist among patients with anal cancer. Factors contributing to these disparities are found at the patient, provider, health system, and public policy levels. Future multilevel interventions targeted at each of these levels will provide opportunities to reduce these disparity gaps and improve anal cancer care for all patient populations.

Precision meets repurposing: Innovative approaches in human papillomavirus and Epstein-Barr virus-driven cancer therapy

Viral malignancies represent a distinct entity among cancers. Oncoviruses like the Human Papilloma Virus (HPV) and the Epstein Barr Virus (EBV) are highly potent inducers of oncogenic transformation leading to tumor development. HPV and EBV are known to be increasingly involved in the pathogenesis of various classes of cancers like cervical, head and neck, colorectal, breast, oral and anogenitial. Therapeutic vaccines directed at such oncoviruses, often fail to unleash the desired immune response against the tumor. This is largely due to the immunosuppressive microenvironment of the virus-induced tumors. Consequently, metronomic chemotherapies administered in conjunction with therapeutic viral vaccines have considerably enhanced the antitumor activity of these vaccines. Moreover, given the unique attributes of HPV and EBV-associated cancers, therapeutic agents directly targeting the oncoproteins of these viruses are still obscure. In this light, an increasing number of reports have evidenced the repurposing of drugs for therapeutic benefits in such cancers. This work delineates the significance and implications of metronomic chemotherapy and drug repurposing in HPV and EBV-associated cancers.

Prevalence of HPV in anal cancer: exploring the role of infection and inflammation

Anal cancer incidence is rising globally, driven primarily by human papillomavirus (HPV) infection. HPV, especially high-risk types 16 and 18, is considered a necessary cause of anal squamous cell carcinoma. Certain populations like people living with HIV, men who have sex with men, inflammatory bowel disease patients, smokers, and those with compromised immunity face elevated risk. Chronic inflammation facilitates viral persistence, cell transformation, and immune evasion through pathways involving the PD-1/PD-L1 axis. HIV coinfection further increases risk by impairing immune surveillance and epithelial integrity while promoting HPV oncogene expression. Understanding these inflammatory processes, including roles of CD8 + T cells and PD-1/PD-L1, could guide development of immunotherapies against anal cancer. This review summarizes current knowledge on inflammation's role in anal cancer pathogenesis and the interplay between HPV, HIV, and host immune factors.

High Rates of High-risk HPV Anal Infection and Abnormal Cytology in a Cohort of Transgender People Assigned Male at Birth

Background

Transgender people assigned male at birth (TG-AMAB) have higher rates of anal human papillomavirus (HPV) infection and anal cancer compared with cisgender populations. In a cohort of TG-AMAB in Washington DC, we determined the prevalence and epidemiological factors associated with anal high-risk HPV (HR-HPV) infection and cytological abnormalities.

Methods

In an urban academic-community clinic, we recruited adults identifying as a gender different than their sex assigned at birth. Participants provided blood samples, anal swabs for HR-HPV and cytology, and completed surveys on sexual behaviors and use of gender-affirming hormones. Logistic regression was used to identify predictors of HR-HPV and abnormal cytology.

Results

Of 97 TG, 80 were AMAB, of whom 66% were people with HIV (PWH); 73% tested positive for any anal HR-HPV, and 48% had abnormal cytology. Only 24% recalled HPV immunization. While TG-AMAB PWH had increased risk of HPV16 infection (37% vs 8%; P = .014), the prevalence rates of any HR-HPV (80% vs 62%; P = .097) and abnormal cytology (56% vs 32%; P = .085) were similarly elevated regardless of HIV status. Among TG-AMAB, estradiol use was not associated with increased odds of any HR-HPV or abnormal cytology (all P > .05); however, higher testosterone levels were associated with any HR-HPV (P = .014). Age ≥35 years was associated with abnormal cytology in TG-AMAB (59% vs 34%; P = .035).

Conclusions

TG-AMAB have a high prevalence of any HR-HPV and abnormal cytology, regardless of age, HIV status, or hormone use. Given high risk for anal cancer and low rates of HPV vaccination, there is a pressing need for primary and secondary anal cancer prevention strategies targeting this population.

Demographic, clinical, and social characteristics of anal cancer among patients stratified by age (<50 and ≥50 years) in Alabama between 2012 and 2018

BACKGROUND

Anal cancer is increasing globally, with a high number of new cases occurring in highly developed countries, including the U.S. The incidence of anal cancer is higher among people living with HIV (PLHIV), and the U.S. South continues to see higher HIV incidence rates and lagging HPV vaccination rates. We aimed to identify factors associated with early onset anal cancer in Alabama which may help explain cancer disparities in the South.

METHODS

Using a cross-sectional study design, we examined demographic, clinical, and social characteristics among anal cancer patients stratified by diagnosis age (<50 and ≥50 years) in the Alabama cancer registry between 2012 and 2018. We used Wilcoxon rank sums and Pearson chi-square tests to assess associations between age at diagnosis, demographic (i.e., sex, race, marital status), clinical (i.e., BMI, HIV infection, site, stage, and histological type), and social (i.e. social vulnerability) characteristics, and multivariable logistic regression to estimate the odds of early onset cancer.

RESULTS

Among 519 patients with anal cancer in Alabama, 92 (17.7 %) were diagnosed at <50 years. The majority of patients were female (66.5 %) and White (83.4 %). Male sex, Black race, and HIV infection were associated with younger age at diagnosis. Black patients had a 4-fold increased odds of early onset anal cancer compared to White patients (AOR=4.39, CI=1.54-12.49). Black patients disproportionately lived in areas with higher social vulnerability. About 42 % of patients in areas with the highest social vulnerability were diagnosed with stage 3 or 4 cancer. About 8 % of cases were among people aged 35-44 years, which is close to double the proportion of anal cancer cases in this age group in the U.S. (4.7 %).

CONCLUSIONS

Patients who are Black, male, and PLHIV may be at higher risk of early onset anal cancer compared to other populations in the South.

Recent and projected incidence trends and risk of anal cancer among people with HIV in North America

BACKGROUND

Anal cancer risk is elevated among people with HIV. Recent anal cancer incidence patterns among people with HIV in the United States and Canada remain unclear. It is unknown how the incidence patterns may evolve.

METHODS

Using data from the North American AIDS Cohort Collaboration on Research and Design, we investigated absolute anal cancer incidence and incidence trends nationally in the United States and Canada and in different US regions. We further estimated relative risk compared with people without HIV, relative risk among various subgroups, and projected future anal cancer burden among American people with HIV.

RESULTS

Between 2001 and 2016 in the United States, age-standardized anal cancer incidence declined 2.2% per year (95% confidence interval = ‒4.4% to ‒0.1%), particularly in the Western region (‒3.8% per year, 95% confidence interval = ‒6.5% to ‒0.9%). In Canada, incidence remained stable. Considerable geographic variation in risk was observed by US regions (eg, more than 4-fold risk in the Midwest and Southeast compared with the Northeast among men who have sex with men who have HIV). Anal cancer risk increased with a decrease in nadir CD4 cell count and was elevated among those individuals with opportunistic illnesses. Anal cancer burden among American people with HIV is expected to decrease through 2035, but more than 70% of cases will continue to occur in men who have sex with men who have HIV and in people with AIDS.

CONCLUSION

Geographic variation in anal cancer risk and trends may reflect underlying differences in screening practices and HIV epidemic. Men who have sex with men who have HIV and people with prior AIDS diagnoses will continue to bear the highest anal cancer burden, highlighting the importance of precision prevention.

Men who have sex with men experience low anxiety and few barriers to performing anal self or companion examinations: a qualitative study of the Prevent Anal Cancer Palpation Study

While rare in the larger population, anal cancer incidence is significantly higher in groups such as sexual minority men and people living with HIV. This qualitative analysis examined participants' experiences and perceptions of barriers to anal self-examination and anal companion examination through interviews completed as a part of a larger clinical trial. Interviews were conducted online with participants (n = 131) within a week of their baseline appointment between January 2020 and October 2021. Content analysis denoted participants' thoughts and perceptions about anal self-examination and anal companion examinations. Of the 131 cisgender men interviewed (mean age 49.9 years, SD 12.7), 92.4% identified as gay, 54.9% identified as white, 22.1% identified as Black, 19.9% identified as Latino, and 44.3% of participants were living with HIV. Participants did not report feelings of excessive anxiety when an abnormality was detected. However, three salient themes emerged as to why participants may not perform an anal self-examination or anal companion examination: (1) physical limitation(s), (2) potential sexualisation of the examination, and (3) level of comfort discussing anal health. Future work must continue to explore methods that not only decrease stigma surrounding anal health but also bolster feelings of accessibility to perform self and couple examinations.

Pleasurable and problematic receptive anal intercourse and diseases of the colon, rectum and anus

The ability to experience pleasurable sexual activity is important for human health. Receptive anal intercourse (RAI) is a common, though frequently stigmatized, pleasurable sexual activity. Little is known about how diseases of the colon, rectum, and anus and their treatments affect RAI. Engaging in RAI with gastrointestinal disease can be difficult due to the unpredictability of symptoms and treatment-related toxic effects. Patients might experience sphincter hypertonicity, gastrointestinal symptom-specific anxiety, altered pelvic blood flow from structural disorders, decreased sensation from cancer-directed therapies or body image issues from stoma creation. These can result in problematic RAI - encompassing anodyspareunia (painful RAI), arousal dysfunction, orgasm dysfunction and decreased sexual desire. Therapeutic strategies for problematic RAI in patients living with gastrointestinal diseases and/or treatment-related dysfunction include pelvic floor muscle strengthening and stretching, psychological interventions, and restorative devices. Providing health-care professionals with a framework to discuss pleasurable RAI and diagnose problematic RAI can help improve patient outcomes. Normalizing RAI, affirming pleasure from RAI and acknowledging that the gastrointestinal system is involved in sexual pleasure, sexual function and sexual health will help transform the scientific paradigm of sexual health to one that is more just and equitable.

International Anal Neoplasia Society's consensus guidelines for anal cancer screening

The International Anal Neoplasia Society (IANS) developed consensus guidelines to inform anal cancer screening use among various high-risk groups. Anal cancer incidence estimates by age among risk groups provided the basis to identify risk thresholds to recommend screening. Guided by risk thresholds, screening initiation at age 35 years was recommended for men who have sex with men (MSM) and transgender women (TW) with HIV. For other people with HIV and MSM and TW not with HIV, screening initiation at age 45 years was recommended. For solid organ transplant recipients, screening initiation beginning from 10 years post-transplant was recommended. For persons with a history of vulvar precancer or cancer, screening initiation was recommended starting within 1 year of diagnosis of vulvar precancer or cancer. Persons aged ≥45 years with a history of cervical/vaginal HSIL or cancer, perianal warts, persistent (>1 year) cervical HPV16, or autoimmune conditions could be considered for screening with shared decision-making, provided there is adequate capacity to perform diagnostic procedures (high-resolution anoscopy [HRA]). Anal cytology, high-risk (hr) human papillomavirus (HPV) testing (including genotyping for HPV16), and hrHPV-cytology co-testing are different strategies currently used for anal cancer screening that show acceptable performance. Thresholds for referral for HRA or follow-up screening tests are delineated. These recommendations from IANS provide the basis to inform management of abnormal screening results, considering currently available screening tools. These guidelines provide a pivotal foundation to help generate consensus among providers and inform the introduction and implementation of risk-targeted screening for anal cancer prevention.

The accuracy of anal self- and companion exams among sexual minority men and transgender women: The Prevent Anal Cancer Palpation Study

Background

Squamous cell carcinoma of the anus (SCCA) annual incidence among sexual minority men (SMM) with and without HIV is 85/100,000 and 19/100,000 persons, respectively, which is significantly higher than the overall incidence (2/100,000). Since SCCA tumours average ≥30 mm at diagnosis, we assessed the accuracy of individuals to self-detect anal abnormalities.

Methods

The study enrolled 714 SMM and transgender women (SMM/TW), aged 25 to 81 years, in Chicago, Illinois and Houston, Texas during 2020-2022. Individuals were taught the anal self- and companion examinations (ASE/ACE). Then, a clinician performed a digital anal rectal examination (DARE) before participants conducted the ASE or ACE. Accuracy was measured along with factors associated with ASE/ACE and DARE concordance.

Findings

The median age was 40 years (interquartile range, 32-54), 36.8% were living with HIV, and 47.0%, 23.4%, and 23.0% were non-Hispanic white, non-Hispanic Black, and Hispanic. Clinicians detected 245 individuals with abnormalities (median diameter 3 mm). Sensitivity and specificity of the ASE/ACE was 59.6% (95%CI 53.5-65.7%) and 80.2% (95%CI 76.6-83.8%), respectively. Overall concordance was 0.73 (95% CI 0.70-0.76) between ASE/ACE and DARE and increased with increasing anal canal lesion size (p=0.02). However, concordance was lower for participants aged ≥55 years (compared to 25-34 years) and when the ASE/ACE trainer was a lay person rather than a clinician.

Interpretation

SMM/TW who complete an ASE or ACE are likely to detect SCCA at an early stage when malignant lesions are much smaller than the current median dimension at presentation of ≥30 mm.

Funding

National Cancer Institute.

Research in context

Evidence before this study: While squamous cell carcinoma of the anus (SCCA) incidence is substantially elevated in people with HIV, there are currently no consensus recommendations on how to screen for it, nor is there widespread technological infrastructure for one prevailing method, high-resolution anoscopy. In the absence of screening programs, the size of SCCA tumours at diagnosis are > 30 mm. We searched PubMed for articles between January 1, 2000 and June 15, 2023 using the search terms 'anus neoplasm' and 'self-examination'. We found no studies assessing the accuracy of self-examinations to detect anal masses other than our prior feasibility study.Added value of this study: The primary goal of the Prevent Anal Cancer Palpation Study was to assess the accuracy of lay self-examinations and companion examinations to recognise abnormalities in the anal region. Clinicians conducted a digital anal rectal examination and recorded all lesions observed at the perianus or anal canal. The median size of lesions was 3 mm. Participants conducted lay examinations and these results were judged against a clinician's examination. The sensitivity and specificity of the lay examinations, for any lesion at the anal canal or perianal region was 59.6% and 80.1%, respectively. As lesions increased in size, concordance increased between clinician's exam and the lay exam.Implications of all the available evidence: It is now known that high-resolution anoscopy can reduce the risk for SCCA but the infrastructure using this technology is very limited in high-resource settings and almost non-existent in low resource settings, especially where HIV prevalence is highest. The evidence suggests that self- and partner examination of the anal region is feasible and that lay persons can detect lesions that are much smaller than the prevailing size of SCCA tumours.

Barriers and facilitators to anal cancer screening among people living with HIV in Puerto Rico

BACKGROUND

Anal cancer (AC) disproportionally affects people living with HIV (PLWH). Although there are no consensus-based AC screening guidelines, experts recommend anal pap as a primary screening tool in settings where high-resolution anoscopy (HRA) is available. We aimed to assess barriers and facilitators to anal cancer screening in a sample of Hispanic PLWH in Puerto Rico.

METHODS

To assess their knowledge and attitudes, we conducted a cross-sectional survey from 2020-2021 among PLWH in Puerto Rico (n = 212). Data was collected through a telephone interview that assessed information on sociodemographics, knowledge, and attitudes about AC, and the history of AC screening. The chi-square test, Fisher exact test, and logistic regression models were used to assess factors associated with screening uptake.

RESULTS

Anal Pap and HRA awareness were 60.4% and 30.7%, respectively. Anal Pap and HRA uptake was 51.5% and 19.3%, respectively. The most common barriers for anal Pap and HRA were lack of knowledge about the test and lack of physician recommendation. MSM were more likely to have heard of anal Pap (OR: 2.15, 95% CI:1.30-3.54) than MSW. MSM (OR: 3.04, 95% CI: 1.79-5.19) and women (OR: 3.00, 95% CI: 1.72-5.20) were also more likely to have undergone anal Pap. Similarly, individuals with a history of genital warts were more likely to have heard of anal Pap and HRA and have undergone anal Pap and HRA. Awareness of where to go for concerns about anal health was positively associated with having received anal Pap and HRA.

CONCLUSIONS

With emerging evidence on the effectiveness of screening and treatment for anal cancer, several organizations are steering toward generating consensus-based anal cancer screening recommendations. Our study provides foundational data on barriers and facilitators to anal cancer screening in Puerto Rico that will be critical to informing screening implementation in this US territory.

Recent Developments in Human Papillomavirus (HPV) Vaccinology

Human papillomavirus (HPV) is causally associated with 5% of cancers, including cancers of the cervix, penis, vulva, vagina, anus and oropharynx. The most carcinogenic HPV is HPV-16, which dominates the types causing cancer. There is also sufficient evidence that HPV types 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59 cause cervical cancer. The L1 protein, which, when assembled into virus-like particles, induces HPV-type-specific neutralising antibodies, forms the basis of all commercial HPV vaccines. There are six licensed prophylactic HPV vaccines: three bivalent, two quadrivalent and one nonavalent vaccine. The bivalent vaccines protect from HPV types 16 and 18, which are associated with more than 70% of cervical cancers. Prophylactic vaccination targets children before sexual debut, but there are now catch-up campaigns, which have also been shown to be beneficial in reducing HPV infection and disease. HPV vaccination of adults after treatment for cervical lesions or recurrent respiratory papillomatosis has impacted recurrence. Gender-neutral vaccination will improve herd immunity and prevent infection in men and women. HPV vaccines are immunogenic in people living with HIV, but more research is needed on the long-term impact of vaccination and to determine whether further boosters are required.