Topical therapies for the treatment of anal high-grade squamous intraepithelial lesions

Anal and Perianal Preneoplastic Lesions

Anal cancer, mainly squamous cell carcinoma, is rare but increasing in prevalence, as is its precursor lesion, anal squamous dysplasia. They are both strongly associated with human papillomavirus infection. The 2-tiered Lower Anogenital Squamous Terminology classification, low-grade SIL and high-grade SIL, is preferred to the 3-tiered anal intraepithelial neoplasia classification because of better interobserver agreement and clearer management implications. Immunohistochemistry with p16 is helpful to corroborate the diagnosis of squamous dysplasia. Similarly, immunohistochemistry is helpful to differentiate primary Paget disease from secondary Paget disease, which is usually due to anal squamous mucosal/epidermal involvement by primary rectal adenocarcinoma.

Sexually Transmitted Human Papillomavirus: Update in Epidemiology, Prevention, and Management

This review presents the epidemiology, pathophysiology, prevention, and management of sexually transmitted human papillomavirus (HPV) and its associated diseases. HPV is the most common sexually transmitted infection worldwide. Prevalence varies regionally. Low-risk strains cause anogenital warts, which can be managed with patient- or provider-applied therapies. High-risk strains cause lower anogenital cancers. Primary and secondary prevention strategies include vaccination and screening for precancerous lesions, respectively. Management of abnormal screening results vary by test result, anatomic site, and individual cancer risk. Approaches include close rescreening, high-resolution visualization with biopsy, and-when biopsy-proven precancer is identified-removal or destruction of the lesion.

Anal Cancer Prevention Through the Topical Use of Single or Dual PI3K/mTOR Inhibitors

INTRODUCTION

Anal dysplasia and anal cancer are major health problems. This study seeks to determine if inhibition of mTOR and/or PI3K pathways is effective at anal cancer prevention in mice with/without established precancerous lesions of the anus (anal dysplasia).

METHODS

K14E6/E7 mice were entered into the study at 5 wk, 15 wk, or 25 wk of age. Mice were treated with a topical carcinogen, 7,12-Dimethylbenz[a]anthracene (DMBA), which ensures carcinoma development within 20 wk. Treatment groups included: no treatment, DMBA only, topical Pictilisib (PI3K inhibitor) with/without DMBA, topical Sapanisertib (mTOR inhibitor) with/without DMBA, and topical Samotolisib (dual PI3K/mTOR inhibitor) with/without DMBA. Mice underwent weekly observations for anal tumor development (tumor-free survival). After 20 wk of treatment, anal tissue was harvested and evaluated histologically for squamous cell carcinoma (SqCC).

RESULTS

All topical treatments in conjunction with DMBA increased tumor-free survival in mice that started treatment at 15 wk of age when compared to DMBA-only treatment, except for Pictilisib + DMBA in males. Topical Sapanisertib increased tumor-free survival in mice regardless of starting treatment age. When examining tissue for microscopic evidence of SqCC, only topical Samotolisib in males decreased SqCC in the 15 wk starting mice.

CONCLUSIONS

Sapanisertib, the mTOR inhibitor, had the greatest effect, in terms of increasing tumor-free survival, regardless of starting time point or sex. Unlike the other treatments, Samotolisib, the dual PI3K/mTOR inhibitor, decreased microscopic evidence of SqCC when starting treatment at 15 wk of age but only in male mice.

The use of a topical protease inhibitor, Saquinavir, to alleviate mouse papillomavirus-mediated anal disease

Select protease inhibitors (PI) have been found to be effective in decreasing human papillomavirus oncoprotein expression. This study evaluated whether the topical PI, Saquinavir (SQV), promotes viral clearance in an infectious mouse model with Mus musculus papillomavirus 1 (MmuPV1). NOD scid gamma (NSG) mice were anally infected with ∼4 × 10⁸ viral genome equivalents of MmuPV1 and 120 days post-infection (when majority have high-grade anal dysplasia), began topical treatments: control (mock), 7,12-dimethylbenz(a)anthracene (DMBA) only, once weekly to promote carcinogenesis, 1% SQV only, daily (Monday - Friday), and SQV + DMBA. Viral MmuPV1 load was analyzed from anal lavages pre and post-treatment. Anal tissue was harvested, processed, and evaluated for drug absorption, grade of anal disease, and anal viral RNA. Results suggest that topical SQV promotes decreased viral shedding in female mice treated with SQV.

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.

Short-term effectiveness and tolerability of carbon dioxide laser for anal high-grade squamous intraepithelial lesions in individuals living with HIV

BACKGROUND

Ablative treatment of intra-anal high-grade squamous intraepithelial lesions (HSIL) reduces the risk of progression to anal squamous cell carcinoma. Our objective was to assess the short-term effectiveness and tolerability of the carbon dioxide laser for treating intra-anal HSIL in patients at high risk of anal cancer.

METHODS

This is an exploratory, pilot, single-arm, clinical trial of treatment response for anal HSIL in people living with HIV diagnosed with ≤3 not previously treated HSILs. Individuals were treated with one carbon dioxide laser treatment session. Clinical assessment by high resolution anoscopy and systematic recording of adverse events was performed.

RESULTS

Fifty-two patients with 72 HSILs were included. Response to treatment was assessed in 48 (92.3%) patients; in the per-protocol population analysis, complete, partial, and no response was seen in 50% (n = 24), 20.8% (n = 10) and 29.1% (n = 14), respectively. Being older than 40 years and having a CD4 T-cell count lower than 200 cells/μL at diagnosis of HSIL were significantly associated with a poor response to treatment. Data on adverse events was recorded for 49 patients and 69.4% (n=34) reported no symptoms after the procedure.

CONCLUSIONS

Carbon dioxide laser ablation is a promising and well tolerated treatment for intra-anal HSIL.

Systemic Delivery of a Dual PI3K/mTOR Inhibitor More Effective than Topical Delivery in Preventing Anal Carcinogenesis in an HPV Transgenic Mouse Model

Introduction

Anal dysplasia is a growing health concern that over time can result in squamous cell carcinoma (SqCC) of the anus. In this study, we compare a topical versus systemic (oral) administration of LY3023414, a dual PI3K/mTOR inhibitor, to prevent anal carcinogenesis in a Human Papillomavirus (HPV) mouse model of anal cancer.

Materials and Methods

K14E6/E7 transgenic mice were used to model HPV-induced anal carcinogenesis. Mice with varying starting anal histologies (normal histology, low-grade, and high-grade anal dysplasia) were treated topically at the anus or systemically via oral gavage with LY3023414 with or without topical carcinogen for 20 weeks. Mice were monitored for overt anal tumor development and anal tissue was assessed for histology and markers of PI3K and mTOR activity (pAKT and pS6, respectively).

Results

LY3023414 treatment, regardless of the mode of delivery, significantly decreased overt tumor development in mice starting with normal histology and low-grade anal dysplasia. Systemic LY3023414 treatment was more effective in delaying tumor onset than topical treatment. Mice treated with systemic LY3023414 had significantly reduced rates of anal SqCC when starting with normal and low-grade anal dysplasia compared to topical treatment. Topical treatment was only effective in reducing SqCC in the setting of low-grade dysplasia. LY3023414 inhibition of pAKT and pS6 expression varied with starting histology. Neither treatment mode was effective in the setting of high-grade anal dysplasia.

Conclusion

Systemic LY3023414 treatment was more effective than topical application in delaying the progression of normal anal histology and low-grade dysplasia to anal cancer in HPV-associated mice.

Anal Cancer Screening and Prevention: Summary of Evidence Reviewed for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infection Guidelines

In June 2019 the Centers for Disease Control and Prevention (CDC) convened an advisory group to assist in development of the 2021 CDC sexually transmitted infections (STI) guidelines. The advisory group on anal cancer screening and prevention met to formulate key questions in this field. The group examined published literature and abstracts to assess evidence and give recommendations for development of the CDC guidelines. This article summarizes key questions, evidence, recommendations, and areas for further research for the screening, diagnosis, and prevention of anal cancer.

Design of the ANal Cancer/HSIL Outcomes Research study (ANCHOR study): A randomized study to prevent anal cancer among persons living with HIV

It is well established that persons living with HIV (PLWH) have highly elevated rates of anal HSIL and anal cancer compared with those who are not living with HIV. The 5-year risk of anal cancer following anal HSIL has been reported to be as high as 14.1% among PLWH compared with 3.2% among those who are not living with HIV. To address these concerns, the AIDS Malignancy Consortium completed a large-scale, randomized trial to compare strategies for the prevention of anal cancer among PLWH with anal HSIL. The objective of the study was to determine whether treating anal HSIL was effective in reducing the incidence of anal cancer in PLWH compared with active monitoring. This paper describes the design of the ANal Cancer/HSIL Outcomes Research Study (ANCHOR) with respect to estimating the anal cancer event rate in this high risk population.

Response factors associated with electrocautery treatment of intra-anal high-grade squamous intraepithelial lesions in a population of HIV-positive men who have sex with men

BACKGROUND

Ablative treatment of anal high-grade squamous intraepithelial lesions (HSIL) reduces the risk of progression to anal squamous cell carcinoma.

OBJECTIVES

To identify factors that influence the response to treatment of anal HSIL by electrocautery ablation (ECA) in a population of HIV-positive men who have sex with men (MSM).

DESIGN

Retrospective study of ECA treatment response in a prospectively followed anal dysplasia cohort. HIV-positive MSM diagnosed with anal HSIL were included. Demographic and HIV data were recorded. Response to treatment was assessed by biopsy after at least 18 months of follow-up.

RESULTS

One hundred and twenty-eight HSILs in 91 men were included in this study. The overall response rate at 18 months was 70.3%. The number of electrocautery sessions required (2 ECA sessions vs 1: adjusted odds ratio [aOR] = 0.36 (95%CI 0.13-1.01); >=3 sessions vs 1: aOR = 0.10 (95%CI 0.04-0.29); p < 0.001]) and the history of previous HPV-related anal pathology (previous anal lesions vs no previous lesions AOR = 2.83 (95%CI 1.14-7.02), p = 0.024) were independently associated with response at 18 months. No serious adverse events were reported.

CONCLUSIONS

Consideration should be given to alternative therapies in patients with unresolved HSIL after 1 ECA treatment.

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.

A 2020 update of anal cancer: the increasing problem in women and expanding treatment landscape

INTRODUCTION

Anal cancer is a rare malignancy with increasing incidence, notably in women. This disease is highly associated with HPV infection and its incidence and mortality are currently rising. Most patients present with localized disease which has a high survival after definitive treatment with chemoradiation. For patients who develop metastatic disease or present with this de novo, survival is poor.

AREAS COVERED

This review provides a summary of current literature on anal cancer. With a focus on women, this includes current epidemiological trends, role of HPV, and the current and future treatment landscape, including HPV vaccination and immunotherapy. Screening currently focusses on HIV-positive men, missing most female cases. In curative disease, trials are investigating treatment de-intensification in good prognostic groups. Immunotherapy is showing early promise in the advanced disease setting.

EXPERT OPINION

Similar to cervical cancer, anal cancer is strongly associated with HPV, and therefore, broader implementation of screening programs may reduce its incidence. HPV vaccination is expected to reduce the development of (pre)malignant anal lesions. The emergence of biomarkers will assist patient treatment selection, allowing optimal balance of treatment efficacy and morbidity. It is hoped that new treatment approaches, including immunotherapy, will improve outcomes. International collaboration is needed.

Electrocautery ablation of anal high-grade squamous intraepithelial lesions: Effectiveness and key factors associated with outcomes

BACKGROUND

Electrocautery ablation (EA) is a common treatment modality for patients with anal high-grade squamous intraepithelial lesions (HSILs), but to the authors' knowledge its effectiveness has been understudied. The objective of the current study was to determine ablation outcomes and to identify clinicopathological factors associated with postablation disease recurrence.

METHODS

A total of 330 people living with HIV with de novo intra-anal HSIL who were treated with EA from 2009 to 2016 were studied retrospectively. Using long-term, surveillance high-resolution anoscopy biopsy data, treatment failures were classified as local recurrence (HSIL noted at the treated site at the time of surveillance) or overall recurrence (HSIL noted at treated or untreated sites). The associations between these outcomes and clinical factors were analyzed using Cox proportional hazards models.

RESULTS

Approximately 88% of participants were men who have sex with men. The median age of study  participants was 45.5 years (range, 35-51 years) and approximately 49% had multiple index HSILs (range, 2-6 index HSILs). At a median of 12.2 months postablation (range, 6.3-20.9 months postablation), approximately 45% of participants had developed local recurrence whereas 60% had developed overall recurrence. Current cigarette smoking, HIV viremia (HIV-1 RNA ≥100 copies/mL), and multiple index HSILs were found to be predictive of local recurrence. Overall recurrence was more common in current smokers and those with multiple index lesions. In multivariable models that included human papillomavirus (HPV) genotypes, baseline and persistent infections with HPV-16 and/or HPV-18 were found to be significantly associated with both local and overall recurrence.

CONCLUSIONS

EA is an effective treatment modality for anal HSIL in people living with HIV, but rates of disease recurrence are substantial. Multiple index HSILs, HIV viremia, current cigarette smoking, and both baseline and persistent infection with HPV-16 and/or HPV-18 appear to negatively impact treatment success. Ongoing surveillance is imperative to capture recurrence early and improve long-term treatment outcomes.

The effectiveness and tolerability of imiquimod suppositories to treat extensive intra-anal high-grade squamous intraepithelial lesions/warts in HIV-infected individuals

Topical imiquimod is a potential treatment for intra-anal condyloma and squamous intraepithelial lesions caused by human papillomavirus (HPV). We aimed to assess the effectiveness and tolerability of imiquimod suppositories for the treatment of anal high-grade intraepithelial lesions (HSIL) and condylomas in HIV-infected patients. We conducted a retrospective analysis in a prospectively followed cohort. High-resolution anoscopy was used for diagnosis and assessment following treatment. Patients’ tolerability was assessed with a self-administered survey. Ninety-five patients (94.7% men) were analyzed. All were on combination antiretroviral therapy. Median CD4 T-cell count was 690 cells/µL, 89% had undetectable plasma viral load. Response to imiquimod was seen in 46.3% (complete: 12.5%, partial: 33.8%) in the intent-to-treat analysis, and in 55.2% (complete: 14.9%, partial: 40.3%) in the on-treatment analysis. Higher response rates were observed for anal condyloma compared with HSIL. A significantly poorer response rate was observed in smokers and in individuals with lower nadir CD4 T-cell counts. Imiquimod tolerability was “good” in 57.1% (n = 36), “acceptable” in 33.3% (n = 21), and “poor” in 9.5% (n = 6). Systemic side effects were reported in 20.7% (n = 13). There was no association between treatment effect and tolerability. In conclusion, imiquimod stands as a well-tolerated option for the treatment of HPV-associated intra-anal pathology in HIV-infected individuals.

Anal intraepithelial neoplasia: diagnosis, screening, and treatment

Anal intraepithelial neoplasia (AIN) is a premalignant lesion for anal cancer. It is more commonly found in high-risk patients (e.g., human papilloma virus (HPV)/human immunodeficiency virus infections, post-organ transplantation patients, and men who have sex with men) and development is driven by HPV infection. The incidence of AIN is difficult to estimate, but is heavily skewed by preexisting conditions, particularly in high-risk populations. The diagnosis is made from cytology or biopsy during routine examinations, and can be performed at a primary care provider’s office. A pathologist can then review and classify cells, based on nucleus-to-cytoplasm ratios. The classification of low or high grade can better predict progression from AIN to anal cancer. There is little debate that AIN can develop into anal cancer, and the main rationale for treatment is to delay the progression. Significant controversy remains regarding screening, surveillance, and treatment for AIN. Management options are separated into surveillance (watchful waiting) and interventional strategies. Emerging data suggest that close patient follow up with a combination of ablative and topical treatments may offer the greatest benefit. HPV vaccination offers a unique treatment prior to HPV infection and the subsequent development of AIN, but its use after the development of AIN is limited. Ablative treatment includes excision, fulguration, and laser therapy.