High-resolution anoscopy: Unchartered territory for gastroenterologists?

Deep Learning in High-Resolution Anoscopy: Assessing the Impact of Staining and Therapeutic Manipulation on Automated Detection of Anal Cancer Precursors

INTRODUCTION

High-resolution anoscopy (HRA) is the gold standard for detecting anal squamous cell carcinoma (ASCC) precursors. Preliminary studies on the application of artificial intelligence (AI) models to this modality have revealed promising results. However, the impact of staining techniques and anal manipulation on the effectiveness of these algorithms has not been evaluated. We aimed to develop a deep learning system for automatic differentiation of high-grade squamous intraepithelial lesion vs low-grade squamous intraepithelial lesion in HRA images in different subsets of patients (nonstained, acetic acid, lugol, and after manipulation).

METHODS

A convolutional neural network was developed to detect and differentiate high-grade and low-grade anal squamous intraepithelial lesions based on 27,770 images from 103 HRA examinations performed in 88 patients. Subanalyses were performed to evaluate the algorithm's performance in subsets of images without staining, acetic acid, lugol, and after manipulation of the anal canal. The sensitivity, specificity, accuracy, positive and negative predictive values, and area under the curve were calculated.

RESULTS

The convolutional neural network achieved an overall accuracy of 98.3%. The algorithm had a sensitivity and specificity of 97.4% and 99.2%, respectively. The accuracy of the algorithm for differentiating high-grade squamous intraepithelial lesion vs low-grade squamous intraepithelial lesion varied between 91.5% (postmanipulation) and 100% (lugol) for the categories at subanalysis. The area under the curve ranged between 0.95 and 1.00.

DISCUSSION

The introduction of AI to HRA may provide an accurate detection and differentiation of ASCC precursors. Our algorithm showed excellent performance at different staining settings. This is extremely important because real-time AI models during HRA examinations can help guide local treatment or detect relapsing disease.

Safety, feasibility, and short-term-outcome of anal endoscopic submucosal dissection for anal intraepithelial neoplasia: an option for focal lesions?

BACKGROUND

Anal intraepithelial neoplasia (AIN) appears in three different stages. AIN 1 and AIN 2 (p16 negative) are defined as low risk and unlikely to progress to invasive anal cancer. AIN 2 (p16 positive) and AIN 3 are of high risk and should be treated because progression rates to anal cancer are around 10% and treatment significantly reduces this risk. The correct treatment is still a matter of debate. Human papilloma virus (HPV) plays a role in the development of AIN. Our aim was to assess anal endoscopic dissection (aESD) as an intervention for AIN3.

METHODS

We retrospectively evaluated patients who underwent aESD for AIN 3 between December 2017 and March 2023. The interventional technique itself (duration, complications, size of specimen) and patient outcomes (recurrence, progression to anal cancer, re-intervention) were analyzed.

RESULTS

Fifteen patients with a median age of 52 years (23-78) underwent aESD for AIN 3. All tested specimens were positive for HPV. Median duration of intervention was 56.1 min, one delayed postinterventional bleeding occurred, and specimen size was 12.05 cm2. Median follow-up was 11.17 months. Three recurrences (20%) appeared: one was resected via biopsy and two were again treated with aESD. There was no progression to invasive anal cancer in the follow-up period.

CONCLUSIONS

Anal endoscopic submucosal dissection seems to be a safe and feasible treatment for AIN. Recurrences are seldom and can be treated again with the same method. Nevertheless, indications for resection in comparison to radiofrequency ablation, pharmacological therapy, and watch-and-wait strategy are still unclear.

TRIAL REGISTRATION

Ethics commission of Salzburg, Austria, EK-Nr. 1056/2023. Keywords: Endoscopic submucosal dissection, anal intraepithelial neoplasia, anal cancer.

Impact of a High-Resolution Anoscopy Clinic on Management of Anal Dysplasia in Women Living With HIV

BACKGROUND

The rate of anal squamous cell cancer (aSCC) is increasing among women living with HIV. Treatment of precursor high grade squamous intraepithelial lesions (HSIL) may reduce the risk of progression to aSCC. The objective of this study was to examine effects of a dedicated high-resolution anoscopy (HRA) clinic on management of HSIL in women with HIV.

METHODS

Women living with HIV who underwent anal dysplasia screening at a single institution between 2006 and 2020 were reviewed. Those who underwent screening before (Group A) and after (Group B) the implementation of an HRA program in 2017 were compared. The primary outcome of interest was the successful detection and treatment of HSIL.

RESULTS

A total of 201 women living with HIV underwent anal dysplasia screening between 2006 and 2020. Seventy-seven patients were found to have abnormal anal cytology requiring further treatment: 43 (55.8%) in Group A and 34 (44.2%) patients in Group B. Of the patients with abnormal anal cytology, 76.7% of patients in Group A received further biopsy and treatment, whereas 79.4% of Group B patients underwent subsequent biopsy and treatment. In propensity score weighting logistic regression analysis, the Group B was 4.6 times as likely to diagnosis HSIL on biopsy compared to Group A (OR = 4.60, 95% CI: 1.15 to 18.38, P = .03).

CONCLUSIONS

Anal dysplasia is common among women living with HIV. The establishment of a HRA program was associated with increased identification and treatment of HSIL among women living with HIV, which may prevent the progression to aSCC.

Anal High-risk Human Papillomavirus Infection, Squamous Intraepithelial Lesions, and Anal Cancer in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND

Ulcerative colitis [UC] and Crohn's disease [CD] can be associated with severe comorbidities, namely opportunistic infections and malignancies. We present the first systematic review and meta-analysis evaluating the burden of anal human papillomavirus disease in patients with UC and CD.

METHODS

PubMed, Web of Science, and Scopus were searched until November 2022. Meta-analyses were performed using random effects models. The protocol was recorded at PROSPERO register with the number CRD42022356728.

RESULTS

Six studies, including 78 711 patients with UC with a total follow-up of 518 969 person-years, described the anal cancer incidence rate. For anal cancer incidence rate in CD, six studies were selected, including 56 845 patients with a total follow-up of 671 899 person-years. The incidence of anal cancer was 10.2 [95% CI 4.3 - 23.7] per 100 000 person-years in UC and 7.7 [3.5 - 17.1] per 100 000 person-years in CD. A subgroup analysis of anal cancer in perianal CD, including 7105 patients, was calculated with incidence of 19.6 [12.2 - 31.6] per 100 000 person-years [three studies included]. Few studies described prevalence of anal cytological abnormalities [four studies including 349 patients] or high-risk human papillomavirus [three studies including 210 patients], with high heterogeneity. Prevalence of cytological abnormalities or high-risk human papillomavirus was not associated with pharmacological immunosuppression in the studies included.

CONCLUSION

The incidence of anal cancer is higher in UC than in CD, with the exception of perianal CD. There are limited and heterogeneous data on anal high-risk human papillomavirus infection and squamous intraepithelial lesions prevalence in this population.

Identification and Reporting of Anal Pathology during Routine Colonoscopies

The gold-standard procedure for anal canal examination is anoscopy. Nonetheless, patients are referred for a colonoscopy for many reasons, and a routine exam might provide an opportunity to diagnose anal pathologies, such as hemorrhoids, anal fissures, anal polyps, condylomas, and anal squamous cell carcinoma. It is important to know the main features of these conditions and relevant information to report in order to help guide patient treatment and follow-up.

Accuracy of narrow-band imaging in predicting the histology of anal intraepithelial lesions

BACKGROUND AND AIM

Anal intraepithelial neoplasia (AIN) is the precursor of anal squamous carcinoma, frequently underappreciated by most gastroenterologists. Purpose of the study is to assess the diagnostic accuracy of narrow-band imaging (NBI) in predicting the histology of anal lesions, considering a new NBI classification.

METHODS

This is a retrospective analysis of consecutive patients with suspected anal squamous intraepithelial lesions (SILs) and superficially invasive squamous cell carcinoma (SISCCA) who underwent anorectal-sigmoidoscopy. Three expert endoscopists reviewed all the images collected during colonoscopies in white light and NBI in order to generate a practical classification of three main different NBI patterns.

RESULTS

After the modified Delphi process, the final NBI classification, mainly based on intrapapillary capillary loops (IPCL) changes included three different NBI pattern. NBI pattern I: elongation of IPCL toward epithelial surface; NBI pattern 2: thickened and tortuous IPCL; NBI pattern 3: mosaic-like disposition of IPCL. We found that NBI pattern positively correlated to the histologic type of the lesions and tumor grade (Spearman's rho = 0.9671, P = 0.0000). Among 58 anal lesions included, 41/41 (100%) LSILs have been classified as NBI pattern I, 10/11 (90.91%) HSILs as NBI pattern II, 1/11 HSIL as NBI pattern I, 4/4 SISCCA as NBI pattern III and 2/2 invasive cancer as NBI pattern III. Diagnostic accuracy of NBI pattern II or III in predicting histology differentiating HSIL or SISCCA/IC versus LSIL showed a sensitivity of 100%, (95% CI: 92.3-100%) and a specificity of 94.1% (95% CI: 83.8-98.3%).

CONCLUSION

The accuracy of this new NBI score system in predicting the histology of anal lesions showed encouraging data in term of sensitivity and specificity in differentiating HSIL or SISCCA/IC versus LSIL, but the clinical usefulness and application of these findings should be evaluated in a prospective larger study.

Anal Squamous Intraepithelial Lesions and Anal Cancer Management in Low Resource Settings

A low resource setting (LRS) is defined as a health care system which does not meet the criteria defined by the World Health Organization (WHO) or other national/international organizations in the following areas: infrastructure, materials, and human resources. 1 Patients encounter barriers which limit their access to care and services that are considered standard of care. While LRS is most commonly associated with developing countries, it is easy to overlook communities in developed countries which lack the financial resources to afford basic health care. This article describes the societal implications and barriers to care for both squamous intraepithelial lesions (SILs) and anal cancer in LRS, the existing screening/surveillance approaches, available treatment approaches to anal cancer, and it also discusses potential evidence-based approaches to bridge the gap for these disparities in anal cancer care.

Anal cancer screening and prevention: a review for dermatologists

The incidence of and mortality from anal cancer, predominantly squamous cell carcinoma (SCC), have been increasing since the 1980s, during an era when many common malignancies have seen decreases in mortality. Dermatologists may be more likely to see patients at an increased risk for anal SCC, such as those living with HIV, MSM and those presenting for management of anogenital warts, yet there is little guidance in the field on how to manage these patients. We underwent a project to review the evidence surrounding screening and prevention of anal SCC. HPV vaccination, the main preventative measure for anal SCC, is often underutilized and may not be effective for those most at risk. Screening methods currently include high-risk HPV and anal cytology testing, with high-resolution anoscopy (HRA) reserved for biopsy and confirmatory testing. High-risk HPV testing has been associated with high sensitivity for intraepithelial neoplasia, but low specificity in high-risk groups. Recent meta-analyses examining AIN detection using anal cytology estimate a similarly high sensitivity of 74-87%, with a relatively higher specificity (44-66%) for identifying high-grade AIN. HRA is the gold standard for diagnosis, but its accessibility and cost are deterrents from its use as a screening tool. Cervical cancer screening, initially adopted without significant evidence of its impact, has significantly decreased cervical cancer rates. The argument can be made that rates of anal SCC may also benefit from appropriate screening methods, particularly anal cytology. It is prudent for dermatologists to be aware of the methods available to them in the management of at-risk patients, the data supporting them, and the potential benefits of screening in order to counsel patients appropriately and address the increasing burden of disease.

Recent Trends in Squamous Cell Carcinoma of the Anus Incidence and Mortality in the United States, 2001-2015

BACKGROUND

Squamous cell carcinoma of the anus (SCCA) incidence is rising in the United States. Study of incidence trends by stage at diagnosis, age-specific and birth cohort patterns, and trends in mortality could provide evidence for a true increase and etiological clues for the increase in incidence.

METHODS

Using the US Cancer Statistics dataset, we examined trends in SCCA incidence (2001-2015) and mortality (2001-2016) rates. Join-point regression was used to compute annual and average annual percentage change (AAPC). Incidence patterns by 5-year age group and birth cohort were evaluated using incidence rate ratios (IRRs) and age-period-cohort modeling.

RESULTS

SCCA incidence increased 2.7% per year (95% confidence interval [CI] = 2.1% to 3.3%), with pronounced increases in age groups 50 years and older. Distant-stage SCCA incidence tripled (AAPC = 8.6%, 95% CI = 5.4% to 12.0%, among men and AAPC = 7.5%, 95% CI = 4.8% to 10.2%, among women) and regional-stage SCCA incidence nearly doubled (AAPC = 4.7% for men and women) in both sexes; the AAPC for localized stage was 1.3% (95% CI = 0.6% to 2.0%) in men and 2.3% (95% CI = 1.8% to 2.8%) in women. Compared with adults born circa 1946, recently born black men (born circa 1986) had a nearly fivefold higher risk (IRR = 4.7, 95% CI = 2.1 to 10.2) of SCCA, and the risk doubled among white men (IRR = 2.0, 95% CI = 1.7 to 2.2) and white women (IRR = 2.1, 95% CI = 1.9 to 2.3) born after circa 1960. Anal cancer mortality rates increased 3.1% per year (95% CI = 2.6% to 3.5%) with statistically significant increases in age groups 50 years and older. SCCA incidence-based mortality increased 1.9% annually (95% CI = 0.5% to 3.4%), with a notable (4.9%, 95% CI = 2.4% to 7.3%, per year) rise in adults ages 60-69 years.

CONCLUSION

The increase in SCCA incidence, particularly advanced-stage disease, and a similar increase in mortality suggest a true increase in the occurrence of SCCA. Future research and improved prevention are urgently needed to mitigate the increasing disease burden.

"That's Only for Women": The Importance of Educating HIV-Positive Sexual Minority Men on HPV and High Resolution Anoscopy (HRA)

Gay, bisexual, and other men who have sex with men (MSM) experience disproportionately high burdens of Human Papilloma Virus (HPV)-associated anal cancers. Recent focus has shifted to anorectal cancer prevention through high-resolution anoscopy (HRA); however, little is known about sexual minority men's perceptions, attitudes, or beliefs regarding HRA. We conducted 4 qualitative Focus Group Discussions (FGDs) (n = 15) with sexual minority men, focusing on their beliefs, attitudes, and perceptions of undergoing HRA. Participants discussed their experiences of HPV/HRA as influenced by both their gender and sexuality, including unawareness of HPV disease as a male health issue, challenges relating to female-oriented HPV/HRA language, conception of HPV/HRA as related to prostate health, and connecting their sexual behavior identification as "bottoms" to their need for HRA. As efforts to improve HRA knowledge, access, and uptake among sexual and gender minority communities increase, special attention should be paid to language and messaging choices around HRA.

The importance of anal cancer screening and high-resolution anoscopy to gastroenterology practice

PURPOSE OF REVIEW

Although human papillomavirus (HPV)-related anal squamous cell cancer (ASCC) is rare, its incidence has been rising and in high-risk populations exceeds the incidence of cancers for which screening programs are implemented. Therefore, targeted screening techniques are being evaluated with high-resolution anoscopy (HRA) as the current gold standard because of its ability to detect anal intraepithelial dysplasia (AIN) and premalignant high-grade squamous intraepithelial lesions (HSILs). However, a scarcity of trained providers presents a barrier to screening.

RECENT FINDINGS

ASCC incidence is rising especially in elderly women and young black men. Premalignant HSIL may not only progress to ASCC but also regress. Biomarkers such as HPV type, p16 immunostaining and DNA methylation markers may emerge as predictors of disease progression.HRA with acetic acid and Lugol's iodine staining can be used to detect HSIL and ASCC. Recent studies suggest that anal cancer screening may have an impact on the stage of ASCC at diagnosis and the incidence of anal cancer.The Anal Cancer HSIL Outcomes Research (ANCHOR) study is underway to determine whether treating HSIL effects ASCC incidence.

SUMMARY

Although there are no consensus screening guidelines for anal cancer, it is reasonable to screen high-risk populations with physical examination, anal cytology and HRA. Gastroenterologists can support anal cancer screening programmes through identifying patients at risk, performing noninvasive screening and considering to incorporate endoscopic techniques to examine the anal canal. VIDEO ABSTRACT: http://links.lww.com/COG/A32.

Cervical, anal and oral HPV detection and HPV type concordance among women referred for colposcopy

BACKGROUND

Infection with human papillomaviruses (HPVs) can cause benign and malignant tumours in the anogenital tract and the oropharynx both in men and women. The aim of the presented study was to investigate cervical, anal, and oral HPV-detection rates among women referred to colposcopy for abnormal Cervical Cancer (CaCx) screening results and assess the concordance of HPV-types among these anatomical sites.

METHODS

Women referred to colposcopy at a single centre due to abnormal cytology, conducted for CaCx screening, were subjected to cervical Liquid-based Cytology (LBC) smear testing, anal and oral sampling. Routine colposcopy consisted in multiple biopsies and/or Endocervical Curettage (ECC). HPV-detection was performed by PCR genotyping in all three anatomical sites. In high-risk (hr) HPV-DNA positive samples either from anal canal or oral cavity, anal LBC cytology and anoscopy were performed, or oral cavity examination respectively. Descriptive statistics was used for the analysis of HPV-detection rates and phi-coefficient for the determination of HPV-positivity concordance between the anatomical sites.

RESULTS

Out of 118 referred women, hr. HPV-DNA was detected in 65 (55.1%), 64 (54.2%) and 3 (2.5%) at cervix, anal canal and oral cavity respectively while low-risk HPV-DNA was detected in 14 (11.9%) and 11 (9.3%) at cervix and anal canal respectively. The phi-coefficient for cervix/anal canal was 0.392 for HPV16, 0.658 for HPV31, 0.758 for HPV33, - 0.12 for HPV45, 0.415 for HPV52 and 0.473 for HPV58. All values were statistically significant (p < 0.001).

CONCLUSIONS

The results suggest that most HPV-types, high-risk and low-risk, detected in the cervix of women with prevalent cervical dysplasia, correlate with the ones detected in their anal canal. This particularly applies for the HPV-types included in the nonavalent HPV-vaccine (HPVs 6/11/16/18/31/33/45/52/58).

Video anoscopy: results of routine anal examination during colonoscopies

Background and study aims  Anal examination and video anoscopy (VA) are rarely performed during colonoscopies. The aim of this study is to demonstrate that anal examination and VA provide important information in all routine colonoscopies. Patients and methods  A cross-sectional study was conducted on 12,151 patients screened by VA which were performed during routine outpatient colonoscopy between 2006 and 2018. The aspects studied were: normal examination; hemorrhoidal disease; thrombosed hemorrhoids; anal fissure; perianal Crohn's Disease; perianal fistula; condyloma; polyps; neoplasms; stenosis; bleeding. Results  Of the colonoscopies performed on 12,151 patients, 9,364 cases (77.06 %) presented some alterations. Internal I degree hemorrhoids (5911 - 48.65 %); internal hemorrhoids of II, III and IV degrees (2362 - 19.44 %); thrombosed hemorrhoids (120 - 0.99 %); bleeding (56 - 0.46 %); fissure (415 - 3.42 %); perianal fistula (42 - 0.35 %); perianal Crohn's Disease (34 - 0.28 %); condylomas (18 - 0.15 %); anal stenosis (30 - 0.25 %); other findings (310 - 2.55 %); polyps (62 - 0.51 %), one of which was adenomatous with high-grade dysplasia; four cases of anal canal neoplasia (0.03 %): two cases of squamous cell carcinoma and two cases of adenocarcinoma. Conclusion  The association of routine video anoscopy during colonoscopy improved diagnosis of neoplastic anal lesions, allowed correct classification of the degree of hemorrhoidal disease, helped to confirm the bleeding site and detected other anal pathologies. The main findings were hemorrhoidal diseases, fissures and perianal fistulas. The study suggests that VA should be used in all colonoscopies.

Cytology in Anal Cancer Screening: Practical Review for Clinicians

The incidence and mortality of anal squamous cell carcinoma (SCC) are expected to continue to increase in the next 20 years. High-risk groups for anal SCC, i.e., human immunodeficiency virus (HIV)-positive patients, men who have sex with men (MSM), women with previous genital neoplasia, and solid-organ transplant recipients, have been identified. HIV-positive MSM have the highest risk, and some societies have advocated for anal cancer screening to be done in this population. Screening for anal SCC follows the same principles as that for cervical cancer since there are similarities between the two types of cancers. Anal cytology has been recommended as an initial screening method for high-risk groups, e.g., HIV-positive MSM. Normally, the cytology is liquid based and collected blindly by a clinician using a Dacron swab and it is especially used for internal lesions detection. The sensitivity to predict anal high-grade squamous intraepithelial lesions is higher in immunosuppressed patients with a high burden of the disease. The report should include the classification, normally according to the Bethesda terminology and the sample adequacy, in a manner similar to that for cervical cytology. In cases involving unsatisfactory samples, it is important to repeat the procedure given the prevalence of anal squamous cytological abnormalities in follow-up cytology procedures. The absence of transformation zone cells in anal cytology seems to increase the risk of false-negative results.

New Insights into the Role of Human Papillomavirus in Anal Cancer and Anal Wart Development

Human papillomavirus is associated with several anogenital and oropharyngeal lesions, including warts, premalignant lesions, and cancer. There are specific groups that were identified as high-risk groups for anal squamous cell carcinoma and anal human papillomavirus infection, namely HIV-positive patients, men who have sex with men, women with genital tract neoplasia, and solid organ transplant recipients. Condylomas have classically been considered to be a benign lesion, with an exception made for the Buschke-Loewenstein tumor, but several publications have shown that a high percentage of condylomas harbor high-grade lesions. Due to the similarities between anal and cervical carcinogenesis, anal cancer screening based on anal cytology and referral to high-resolution anoscopy, in case of abnormalities, have been advocated. Testing for anal human papillomavirus is not routinely done in anal cancer screening, because of the very high prevalence in high-risk populations. The large majority of anal cancers are squamous cell carcinomas (SCC), and around 90% are attributed to human papillomavirus. Human papillomavirus positivity in anal SCC seems to have a prognostic value, with better survival in those patients with positive tumors. Prophylactic vaccination has been shown to be important for prevention of anal human papillomavirus-related lesions.

History of High-Resolution Anoscopy

High-resolution anoscopy (HRA) is a form of low-resolution anal microscopy currently utilized in the screening and management of anal squamous dysplasia. No randomized controlled trials, national or international guidelines exist on the use of HRA for this purpose. Much of our understanding of this entity has been adapted from the literature on cervical squamous dysplasia, including the technique of HRA itself. Epidemiologic evidence has shown that the prevalence and incidence of anal dysplasia is highest in HIV-positive populations. The history of this technique parallels the evolution of our understanding of anal dysplasia. To understand the history of the use of HRA and its place in the screening and management of anal squamous dysplasia, we discuss key advances in the understanding of human papillomavirus-related squamous dysplasia. We begin with early reports in the field establishing the link between this virus and squamous dysplasia, through the marked increase in anal cancer seen with the onset of the HIV epidemic, the identification of relevant populations at risk, the performance of the test itself, to its use today.

Anal intraepithelial neoplasia: A review of diagnosis and management

Anal intraepithelial neoplasia (AIN) is a premalignant lesion of the anal mucosa that is a precursor to anal cancer. Although anal cancer is relatively uncommon, rates of this malignancy are steadily rising in the United States, and among certain high risk populations the incidence of anal cancer may exceed that of colon cancer. Risk factors for AIN and anal cancer consist of clinical factors and behaviors that are associated with the acquisition and persistence of human papilloma virus (HPV) infection. The strongest HPV-associated risk factors are HIV infection, receptive anal intercourse, and high risk sexual behavior. A history of HPV-mediated genital cancer, which suggests infection with an oncogenic HPV strain, is another risk factor for AIN/anal cancer. Because progression of AIN to anal cancer is known to occur in some individuals over several years, screening for AIN and early anal cancer, as well as treatment of advanced AIN lesions, is reasonable in certain high-risk populations. Although randomized controlled trials evaluating screening and treatment outcomes are lacking, experts support routine screening for AIN in high risk populations. Screening is performed using anal cytological exams, similar to those performed in cervical cancer screening programs, along with direct tissue evaluation and biopsy via high resolution anoscopy. AIN can be treated using topical therapies such as imiquimod, 5-flurouracil, and trichloroacetic acid, as well as ablative therapies such as electrocautery and laser therapy. Reductions in AIN and anal cancer rates have been shown in studies where high-risk populations were vaccinated against the oncogenic strains of HPV. Currently, the CDC recommends both high-risk and average-risk populations be vaccinated against HPV infection using the quadrivalent or nonavalent vaccines. It is important for clinicians to be familiar with AIN and the role of HPV vaccination, particularly in high risk populations.