Anal intraepithelial neoplasia: diagnosis, screening, and treatment

Anal carcinoma - exploring the epidemiology, risk factors, pathophysiology, diagnosis, and treatment

Anal carcinoma is a relatively rare tumor that accounts for approximately 2% of gastrointestinal malignancies and less than 7% of anorectal cancers. Most anal tumors originate between the anorectal junction and the anal verge. Risk factors for the disease include human papillomavirus infection, human immunodeficiency virus, tobacco use, immunosuppression, female sex, and older age. The pathogenesis of anal carcinoma is believed to be linked to human papillomavirus-related inflammation, leading to dysplasia and progression to cancer. Squamous cell carcinoma is the most common type of anal tumor, with an annual incidence of approximately 1 to 2 per 100000 persons. Treatment regarding anal cancer has emerged over time. However, chemoradiation therapy remains the mainstay approach for early localized disease. Patients with metastatic disease are treated with systemic therapy, and salvage surgery is reserved for disease recurrence following chemoradiation. This article aims to provide background information on the epidemiology, risk factors, pathology, diagnosis, and current trends in the management of anal cancer. Future directions are briefly discussed.

Clinical application of endoscopic submucosal dissection for superficially invasive squamous cell carcinoma/high-grade squamous intraepithelial lesion involving the canal anal

BACKGROUND

Superficially invasive squamous cell carcinoma (SISCC) and high-grade squamous intraepithelial lesions (HSIL) involving the anal canal are rare, and their surgical management involves local excision. Endoscopic submucosal dissection (ESD) has recently emerged as a promising treatment. This study aimed to evaluate the feasibility and safety of ESD for SISCC and HSIL in the anal canal.

METHODS

All patients diagnosed with SISCC or HSIL in the anal canal who underwent ESD between November 2018 and May 2023 were included. Patient age, sex, pathology, human immunodeficiency virus (HIV) status, human papillomavirus (HPV) status, T stage, en bloc rate, and R0 resection rate were analyzed.

RESULTS

Ten patients, including two men and eight women, with a median age of 61 (51-68) years were enrolled. All patients were HIV-negative, but five (50%) were HPV-positive. Pathological examination showed tumor stage of two patients as T2, one as T0 of SISCC, and seven as Tis of HSIL. The median specimen and tumor sizes were 24 (6-65) mm and 18 (6-55) mm, respectively. The en bloc and R0 resection rates were 100% and 80%, respectively. No severe complications occurred and no recurrence was observed at the follow-up (median follow-up period, 9 (1-35) months).

CONCLUSIONS

ESD is a reliable and minimally invasive procedure that enables more individualized treatment options for specific groups. As we were limited by the length of the observation period, the long-term performance of ESD for SISCC and HSIL involving the anal canal requires further investigation.

Anal cancer screening among women with HIV: provider experiences and system-level challenges

Women living with HIV (WLWH) are at increased risk of anal cancer compared to women without HIV, often due to persistent human papillomavirus (HPV) infections. This paper describes current practices and challenges conducting anal cancer screening for WLWH at an urban integrated safety-net system and a non-profit community-based HIV clinic. We conducted 25 semi-structured interviews with clinical and administrative stakeholders to assess knowledge, clinic practices and procedures, and experiences with anal cancer screening. Interview transcripts and fieldnotes were thematically analyzed using an iterative deductive and inductive coding scheme. Findings were organized by the Consolidated Framework for Implementation Research (CFIR) domains and constructs. Provider-level barriers to conducting anal cancer screening included limited knowledge of guidelines. System-level barriers included: structural characteristics such as lack of coordination between clinics to discern provider roles and responsibilities; and limitations in available resources such as configuration of electronic health records and infrastructure to manage referrals of abnormal anal Pap results. We conclude that anal cancer screening and follow-up for WLWH requires organization and coordination between multiple care teams, updated clinical information systems to facilitate communication and support anal Pap ordering and result documentation, and infrastructure that includes policies and protocols for management of abnormal results.Trial registration: ClinicalTrials.gov identifier: NCT02135419.

High-grade anal intraepithelial neoplasia treated with endoscopic submucosal dissection: a case report

Anal intraepithelial neoplasia is a premalignant lesion for anal squamous cell carcinoma. Current treatment options, consisting of topical therapy and local ablative procedures with electrocautery or radiofrequency ablation, are effective although recurrence rates are high. Experience with endoscopic submucosal dissection for anal lesions is limited, with only a few cases of anal intraepithelial neoplasia and early anal squamous cell carcinoma. We present a 65-year-old woman with high-grade anal intraepithelial neoplasia successfully removed by endoscopic submucosal dissection with no complications or signs of recurrence after 5 months, suggesting that this technique could be a safe and effective approach for management of anal premalignant lesions.

Definitive Radiotherapy for Patients With Anal Squamous Cell Carcinoma: A Retrospective Cohort Study

Background

Anal squamous cell carcinoma accounts for less than 2-3% of all digestive system carcinomas. The present study aimed to determine the clinical characteristics, treatment patterns, and treatment outcomes of patients at our institution.

Methodology

We reviewed the clinical data of all consecutive patients with anal squamous cell carcinoma who were treated with definitive radiotherapy in our department between July 2009 and July 2020. Radiotherapy was delivered in 1.8-2 Gy daily fractions to a whole pelvic dose ranging from 45 to 50 Gy, followed by boost radiotherapy of 10-15 Gy, resulting in a total dose of approximately 60 Gy. Concurrent chemotherapy with radiotherapy included 5-fluorouracil/mitomycin C or 5-fluorouracil/cisplatin.

Results

A total of 14 patients with a median age of 61.5 years (range: 45-85 years) were analyzed. There were nine women and five men. The clinical T stage was T1 in two patients, T2 in six patients, T3 in two patients, and T4 in four patients. The clinical N stage was N0 in four patients and N1 in 10 patients. Patients with clinical stage III disease comprised 79% of the entire study population. For the entire cohort, the five-year overall survival rate was 83.3% and the five-year progression-free survival rate was 48.5%. One patient experienced grade 3 fecal incontinence, and the others experienced no radiation-induced severe delayed adverse events.

Conclusions

The results of our study demonstrated that definitive radiotherapy with or without chemotherapy for patients with anal squamous cell carcinoma is an effective and feasible treatment.

HPV genotyping and risk factors for anal high-risk HPV infection in men who have sex with men from Toronto, Canada

Men who have sex with men (MSM) are disproportionately affected by anal cancer, predominantly caused by high-risk (HR) human papillomavirus (HPV) infection. Currently, the nonavalent HPV vaccine provides coverage against nine HPV genotypes, including seven HR-HPV genotypes. Here, we characterize anal HR-HPV genotype distribution and associated risk factors in MSM from Toronto, Canada recruited between September 2010 and June 2012. Wilcoxon-Mann-Whitney test was used for continuous variables, Chi-square test was performed for categorical variables, and a multivariable model using logistic regression was created to assess for correlates of anal HR-HPV infection. A total of 442 MSM were recruited, with a median age of 45 (IQR 38-50) and an overall HPV prevalence of 82%. The prevalence of any HR-HPV infection was 65.3% and 50.7% in the HIV-positive and HIV-negative MSM, respectively. No participant tested positive for all genotypes covered by the nonavalent vaccine. HIV status (aOR 1.806; 95% CI 1.159-2.816), smoking (aOR 2.176; 95% CI 1.285-3.685) and the number of lifetime sexual partners (aOR 2.466; 95% CI 1.092-5.567) were independent risk factors for anal HR-HPV infection. Our findings will be useful to inform HPV vaccine rollout and HPV prevention strategies in Canadian MSM.

Risk factors for ≥high-grade anal intraepithelial lesions in MSM living with HIV and the response to topical and surgical treatments

Background

The objective of this study in MSM living with HIV was to determine the incidence of HSIL and ASCC, related factors, and the response to treatment.

Patients and methods

Data were gathered in 405 consecutive HIV-infected MSM (May 2010-December 2018) at baseline and annually on: sexual behavior, anal cytology, and HPV PCR and/or high-resolution anoscopy results. They could choose mucosectomy with electric scalpel (from May 2010) or self-administration of 5% imiquimod 3 times weekly for 16 weeks (from November 2013). A multivariate logistic regression model was developed for ≥HSIL-related factors using a step-wise approach to select variables, with a significance level of 0.05 for entry and 0.10 for exit, applying the Hosmer-Lemeshow test to assess the goodness of fit.

Results

The study included 405 patients with a mean age of 36.2 years; 56.7% had bachelor´s degree, and 52.8% were smokers. They had a mean of 1 (IQR 1–7) sexual partner in the previous 12 months, median time since HIV diagnosis of 2 years, and mean CD4 nadir of 367.9 cells/uL; 86.7% were receiving ART, the mean CD4 level was 689.6 cells/uL, mean CD4/CD8 ratio was 0.77, and 85.9% of patients were undetectable. Incidence rates were 30.86/1,000 patient-years for ≥high squamous intraepithelial lesion (HSIL) and 81.22/100,000 for anal squamous cell carcinoma (ASCC). The ≥HSIL incidence significantly decreased from 42.9% (9/21) in 2010 to 4.1% (10/254) in 2018 (p = 0.034). ≥HSIL risk factors were infection with HPV 11 (OR 3.81; 95%CI 1.76–8.24), HPV 16 (OR 2.69, 95%CI 1.22–5.99), HPV 18 (OR 2.73, 95%CI 1.01–7.36), HPV 53 (OR 2.97, 95%CI 1.002–8.79); HPV 61 (OR 11.88, 95%CI 3.67–38.53); HPV 68 (OR 2.44, CI 95% 1.03–5.8); low CD4 nadir (OR1.002; 95%CI 1–1.004) and history of AIDS (OR 2.373, CI 95% 1.009–5.577). Among HSIL-positive patients, the response rate was higher after imiquimod than after surgical excision (96.7% vs 73.3%, p = 0.009) and there were fewer re-treatments (2.7% vs 23.4%, p = 0.02) and adverse events (2.7% vs 100%, p = 0.046); none developed ASCC.

Conclusions

HSIL screening and treatment programs reduce the incidence of HSIL, which is related to chronic HPV infection and poor immunological status. Self-administration of 5% imiquimod as first-line treatment of HSIL is more effective than surgery in HIV+ MSM.