High-resolution anoscopy in the diagnosis of anal cancer precursor lesions in renal graft recipients

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.

Carcinogenesis and Cancer Progression in De Novo Anal Squamous Cell Carcinoma After Organ Transplantation: A Systematic Review

Our aim was to perform a comprehensive literature review on the pathogenesis of squamous anal cancerin patients after solid-organ transplant. Medical databases were consulted until June 1, 2020, for potentially relevant publications.All studies on pathogenesis of de novo anal squamous cell carcinoma in solid-organ transplant recipients were included. Two researchers independently performed study selection, quality assessment, and data extraction and analysis. Twenty-one studies were included.None ofthe selected papers had been solely focused on carcinogenesis. Most ofthe studies identified human papillomavirus infection and immunosuppression to be significantly correlated with the development of de novo anal cancer in adult solid organ transplant recipients. CD4+ T-cell depletion and inactivation oftumor suppressor pathways were mainly implicated. All solid-organ transplant recipients, especially those who were human papillomavirus positive, were shown to be at increased risk for the development of posttransplant anal cancer. Further studies are needed to determine the specific mechanisms of pathogenesis according to different solid-organ transplant populations.

Risk of Anal High-grade Squamous Intraepithelial Lesions Among Renal Transplant Recipients Compared With Immunocompetent Controls

BACKGROUND

Renal transplant recipients (RTRs) have increased risk of human papillomavirus (HPV)-related cancers, including anal cancer. We investigated the prevalence of anal high-grade intraepithelial lesions (HSILs) in RTRs compared with immunocompetent controls and risk factors for anal HSIL in RTRs.

METHODS

We included 247 RTRs and 248 controls in this cross-sectional study. We obtained anal samples for HPV testing with INNO-LiPA and performed high-resolution anoscopy on all participants. The participants completed a questionnaire on lifestyle and sexual habits. We used logistic regression to estimate odds ratios (ORs) of histologically confirmed anal HSIL in RTRs vs controls and risk factors for anal HSIL in RTRs, stratified by sex and anal high-risk (hr) HPV status, adjusting for age, smoking, lifetime sexual partners, and receptive anal sex.

RESULTS

RTRs had higher anal HSIL prevalence than controls, both among men (6.5% vs 0.8%; adjusted OR [aOR], 11.21 [95% confidence interval {CI}, 1.46-291.17]) and women (15.4% vs 4.0%; aOR, 6.41 [95% CI, 2.14-24.10]). Among those with anal hrHPV, RTRs had higher anal HSIL prevalence than controls (33.8% vs 9.5%; aOR, 6.06 [95% CI, 2.16-20.27]). Having had receptive anal sex (aOR, 6.23 [95% CI, 2.23-19.08]) or genital warts (aOR, 4.21 [95% CI, 1.53-11.48]) were risk factors for anal HSIL in RTRs. All HSIL cases occurred in individuals with anal hrHPV.

CONCLUSIONS

RTRs had increased risk of anal HSIL compared with immunocompetent controls, with particularly high prevalence in female RTRs. Receptive anal sex, previous genital warts, and anal hrHPV infection were risk factors for anal HSIL in RTRs. Screening for anal HSIL in RTRs should be considered.

CLINICAL TRIALS REGISTRATION

NCT03018927.

Retrospective 15-Year Review of Anal Cytology Screening in Women at Mayo Clinic Rochester, Minnesota

OBJECTIVES

Anal cytology is a modality for anal cancer screening in high-risk women. In this retrospective study, we review risk factors associated with abnormal anal cytology and unsatisfactory anal cytology rates, and correlate findings of cytology with histological results.

METHODS

A retrospective cohort study of anal cytology screening in women at Mayo Clinic in Rochester, Minnesota from 2002 to 2018 was conducted.

RESULTS

Three hundred fifty-seven women had a total of 592 anal cytologies performed. Three hundred seventeen women had screening anal cytology, whereas 40 women had anal cytology for surveillance given a history of anal intraepithelial neoplasia (AIN) or anal cancer. An unsatisfactory anal cytology result was found in 14.7%. Risk factors, type of follow-up, and correlation with histologic specimens were also reviewed. Histologic finding of AIN 2/3 correlated with abnormal anal cytology 84% of the time in this cohort.

CONCLUSIONS

High-risk women should be screened on a periodic basis for anal cancer. Anal cytology is one possible modality that can be used. Further insight into AIN progression, regression, recurrence, and outcome after treatment will help direct future screening recommendations.

Burden of anal squamous cell carcinoma, squamous intraepithelial lesions and HPV16 infection in solid organ transplant recipients: A systematic review and meta-analysis

The number of solid organ transplant recipients (SOTR), and their life expectancy, is increasing, with higher risk for long-term complications from immunosuppression. We carried out a systematic review describing the burden of anal squamous cell carcinoma (SCC), and its surrogates, in SOTR. We conducted mixed effect model-based meta-analyses evaluating incidence of anal SCC (standardized incidence ratio [SIR] vs general population, and absolute incidence rate [IR]), prevalence of anal squamous abnormalities, and human papillomavirus (HPV) 16. Generalized I2 statistics were calculated, quantifying heterogeneity. Anal SCC incidence in SOTR was elevated vs the general population (pooled SIR = 6.8, 95% confidence interval [CI], 4.3-10.9; 6 studies including 241 106 SOTR; I2  = 82.3%), with an absolute IR of 12.3 (95% CI, 10.4-14.7) per 100 000 person-years (5 studies including 1 079 489 person-years; I2  = 0%). Prevalence of abnormal anal cytology was 12.9% (95% CI, 9.2%-17.7%; 6 studies including 328 SOTR; I2  = 17.4%). For histology, the pooled prevalence estimate of anal squamous intraepithelial lesions was 22.4% (95% CI, 17.3%-28.5%; 3 studies including 214 SOTR; I2  = 0%), with 4.7% (95% CI, 2.5%-8.5%; I2  = 0%) high-grade squamous intraepithelial lesions. Pooled anal HPV16 prevalence was 3.6% (95% CI, 1.6%-7.8%; 4 studies including 254 SOTR; I2  = 17.6%). There was substantial and consistent evidence of elevated anal SCC incidence in SOTR.

Multidisciplinary Approach to the Management and Treatment of Anal Dysplasia

The incidence of anal intraepithelial neoplasia (AIN) has been increasing over the years. AIN acts as a precursor lesion for anal squamous cell cancer. Factors leading to progression of AIN into malignancy are complex and involve grade of the lesion, human papillomavirus and HIV coinfection, as well as patient-related risk factors such as immunocompromised state and men who have sex with men. The multifaced aspects of this disease make its management challenging, as it involves several disciplines including pathology, primary care, infectious disease, and colorectal specialties. Each of these fields brings its own expertize to the management of AIN, and their collaborative, coordinated work culminates into best practice and optimized outcomes in the care of the AIN patient.

Basic Science, Epidemiology, and Screening for Anal Intraepithelial Neoplasia and Its Relationship to Anal Squamous Cell Cancer

Despite the progress made in the reduction of squamous cell carcinoma of the cervix, the incidence of anal squamous cell carcinoma (ASCC) has been increasing since 1992. While it remains an uncommon disease, the prevalence is climbing steadily. Among human immunodeficiency virus (HIV)-infected adults, especially men who have sex with men, ASCC is one of the more common non-AIDS-defining malignancies. The precursor lesion, anal intraepithelial neoplasia (AIN), is prevalent in the HIV-infected population. More than 90% of ASCCs are related to human papilloma virus (HPV), oncogenic types (HPV 16, 18). While the biology of HPV-related intraepithelial neoplasia is consistent in the anogenital area, the natural history of AIN is poorly understood and is not identical to cervical intraepithelial neoplasia (CIN). CIN is also considered an AIDS-defining malignancy, and the methods for screening and prevention of AIN are derived from the CIN literature. This article will discuss the epidemiology of ASCC and its association with HPV and the life cycle of the HPV, and the molecular changes that lead to clearance, productive infection, latency, and persistence. The immunology of HPV infection will discuss natural immunity, humoral and cellular immunity, and how the HPV virus evades and interferes with these mechanisms. We will also discuss high-risk factors for developing AIN in high-risk patient populations with relation to infections (HIV, HPV, and chlamydia infections), prolonged immunocompromised people, and sexual behavior and tobacco abuse. We will also discuss the pre- and post-HAART era and its effect on AINs and ASCC. Finally, we will discuss the importance of anal cytology and high-resolution anoscopy with and without biopsy in this high-risk population.

Anal human papillomavirus infection: prevalence, diagnosis and treatment of related lesions

Human papillomavirus (HPV) infection is mostly asymptomatic, but may also have many diverse clinical signs encompassing benign ano-genital lesions, and carcinomas. Recently, interest has also particularly focused on anal cancer since, over the last decades, its incidence has been greatly increasing in developed countries, both in women and men and is drastically higher in specific risk groups, such as men who have sex with men (MSM) and HIV-1 infected individuals. Approximately 88% of anal cancer cases worldwide are associated with HPV infection. This review summarizes our current understanding of anal HPV infection, discussing its epidemiology and risk factors in various populations, and the state of the art in the detection of anal HPV infection and its related lesions through both cytology and histology. Finally, we discuss the clinical management and therapy for these lesions.

A Case Series of Anal Carcinoma Misdiagnosed as Idiopathic Chronic Anal Fissure

Chronic anal fissure is a linear ulcer in the anal canal that has not cicatrized for more than 8-12 weeks of treatment. Most anal fissures are idiopathic and are located in the posterior midline. Squamous cell carcinoma of the anus commonly presents as bleeding and anal pain. It may also present as a mass, nonhealing ulcer, itching, discharge, fecal incontinence and fistulae. Not uncommonly, small and early cancers are misdiagnosed as benign anorectal disorders like anal fissures or hemorrhoids. The clinical suspicion of squamous cell carcinoma of the anus is of paramount importance in patients with nonhealing anal fissures, fissures in atypical positions or with indurated or ulcerated anal tags and in patients with risk factors for the development of anal squamous intraepithelial lesions that are precursors of invasive anal squamous cell carcinoma. The authors present 3 cases of squamous cell carcinoma of the anus initially misdiagnosed as benign chronic anal fissure.

Screening, Surveillance, and Treatment of Anal Intraepithelial Neoplasia

The prevalence of anal intraepithelial neoplasia has been increasing, especially in high-risk patients, including men who have sex with men, human immunodeficiency virus positive patients, and those who are immunosuppressed. Several studies with long-term follow-up have suggested that rate of progression from high-grade squamous intraepithelial lesions to invasive anal cancer is ∼ 5%. This number is considerably higher for those at high risk. Anal cytology has been used to attempt to screen high-risk patients for disease; however, it has been shown to have very little correlation to actual histology. Patients with lesions should undergo history and physical exam including digital rectal exam and standard anoscopy. High-resolution anoscopy can be considered as well, although it is of questionable time and cost-effectiveness. Nonoperative treatments include expectant surveillance and topical imiquimod or 5-fluorouracil. Operative therapies include wide local excision and targeted ablation with electrocautery, infrared coagulation, or cryotherapy. Recurrence rates remain high regardless of treatment delivered and surveillance is paramount, although optimal surveillance regimens have yet to be established.

A wide field-of-view scanning endoscope for whole anal canal imaging

We report a novel wide field-of-view (FOV) scanning endoscope, the AnCam, which is based on contact image sensor (CIS) technology used in commercialized business card scanners. The AnCam can capture the whole image of the anal canal within 10 seconds with a resolution of 89 μm, a maximum FOV of 100 mm × 120 mm, and a depth-of-field (DOF) of 0.65 mm at 5.9 line pairs per mm (lp/mm). We demonstrate the performance of the AnCam by imaging the entire anal canal of pigs and tracking the dynamics of acetowhite testing. We believe the AnCam can potentially be a simple and convenient solution for screening of the anal canal for dysplasia and for surveillance in patients following treatment for anal cancer.

Phase I study demonstrates safety and tolerability of radiofrequency ablation (RFA) of the anal mucosa

BACKGROUND

Anal carcinoma is increasing in high-risk populations. Dysplasia is often distributed throughout the anal mucosa, and focal ablative techniques have high rates of recurrence.

METHODS

With the goal of eradicating dysplasia from the entire anal mucosa, we conducted a phase I dose-ranging study to determine the safety and tolerability of radiofrequency ablation (RFA). HIV-infected individuals with high-grade anal intraepithelial neoplasia underwent RFA of the anal mucosa. Patient-reported procedural and postprocedural symptoms were recorded, and mucosal healing was visually assessed.

RESULTS

Four groups of 3 subjects each were treated with incrementally increasing numbers of RF pulses (1-3) applied to a single area of anal mucosa. Two or three doses of 12 J/cm2 were found to have acceptable patient tolerance and healing of the mucosa within 4 weeks of ablation. Using these doses, 2 groups underwent ablation of 180° of contiguous mucosa. Subjects experienced a loss of 1 to 3 days of daily activities of living, 7 to 14 days of postprocedure symptoms, and mucosal healing within 4 weeks. One subject in the first treatment group had the procedure aborted due to severe procedural pain.

CONCLUSIONS

The study provides evidence of the safety and tolerability of anal RFA of 180° of contiguous mucosa in a single procedure and will allow future RFA efficacy studies in the treatment of anal dysplasia.

Prevalence of abnormal anal cytology and high-grade squamous intraepithelial lesions among a cohort of HIV-infected men who have sex with men

BACKGROUND

The incidence of anal cancer among HIV-infected patients is higher than that in other populations. Anal high-grade squamous intraepithelial lesions are considered precursors to invasive squamous-cell carcinomas and are strongly associated to high-risk human papillomavirus infection.

OBJECTIVE

The aim of this study is to determine the prevalence of anal high-grade squamous intraepithelial lesions through screening based on cytology and high-resolution anoscopy with biopsy in a cohort of HIV-infected men who have sex with men.

DESIGN

This investigation is an observational cross-sectional cohort study.

SETTING

The study was conducted in the HIV unit of a tertiary hospital in Spain.

PATIENTS

Three hundred HIV-infected men who have sex with men participated. Physical examination led to a diagnosis of perianal squamous-cell carcinoma and high-grade squamous intraepithelial lesions in 2 patients who were then excluded.

INTERVENTIONS

Anal liquid cytology was performed. Patients with cytological abnormalities underwent high-resolution anoscopy and biopsy.

MAIN OUTCOME MEASURE

The primary outcome measured was biopsy-proven high-grade squamous intraepithelial lesions.

RESULTS

The median age was 41 ± 10.5 years. The mean and nadir CD4 cell counts were 651 ± 205 cells/mm(3) (interquartile range, 438-800) and 273 ± 205 cells/mm(3) (interquartile range, 131-362). High-risk human papillomavirus was detected in 80.9% of patients, and human papillomavirus 16 was detected in 35.9% of patients. The mean number of human papillomavirus genotypes was 4.6 ± 2.9 (CI, 2-6). Anal cytology was abnormal in 40.9% of patients (n = 122/298; interquartile range, 35.4%-46.6%). High-resolution anoscopy and biopsies were performed in 119 patients. The results of histological analyses were as follows: normal, 7.7% (n = 23); condyloma, 4.3% (n = 13); anal intraepithelial neoplasia 1, 5.7% (n = 17); anal intraepithelial neoplasia 2, 14% (n = 42); and anal intraepithelial neoplasia 3, 8% (n = 24). The overall prevalence of high-grade squamous intraepithelial lesions among patients with abnormal cytology was 54% (95% CI, 45.1%-62.8%). A diagnosis of high-grade squamous intraepithelial lesions was associated with human papillomavirus 16 and human papillomavirus 51 infection, and with detection of a higher number of human papillomavirus genotypes.

LIMITATIONS

High-resolution anoscopy was only performed in patients with abnormal cytology.

CONCLUSIONS

The prevalence of high-risk human papillomavirus infection and high-grade squamous intraepithelial lesions is high in our cohort. Physical examination enabled straightforward diagnosis of perianal high-grade squamous intraepithelial lesions and squamous-cell carcinoma in 2 patients.

Variabilidade interobservadores no diagnóstico de lesões precursoras do câncer anal: estudo do cenário habitual

OBJETIVO: Analisar a variabilidade interobservadores no diagnóstico de lesões precursoras do câncer anal no cenário mais comum de um serviço constituído por patologistas sem experiência prévia no diagnóstico destas lesões. MÉTODOS: Quinhentas e duas lâminas histopatológicas com espécimes anais retirados de 372 pacientes HIV-positivos e HIV-negativos foram analisadas no Departamento de Patologia da Fundação de Medicina Tropical do Amazonas por três patologistas com ampla experiência no diagnóstico de doenças tropicais e infecciosas, mas sem experiência prévia importante no diagnóstico de lesões precursoras do câncer anal. As leituras individuais de cada patologista foram comparadas com a que se seguiu a diagnóstico de consenso em microscópio de ótica compartilhada. Os diagnósticos individuais foram confrontados com os de consenso mediante análise da estatística kappa. RESULTADOS: A concordância absoluta entre cada diagnóstico individual e o de consenso correspondente foi ruim (kappa=-0,002). Considerando os resultados apenas positivos ou negativos para lesões intraepiteliais escamosas anais, obteve-se concordância regular entre os observadores (kappa=0,35), enquanto que a concordância foi moderada quando os resultados histopatológicos foram considerados positivos ou negativos para lesão intraepitelial de alto grau ou câncer (kappa=0,52). CONCLUSÃO: A variabilidade interobservadores no diagnóstico histopatológico do câncer anal e de suas lesões precursoras entre patologistas sem grande experiência na área, apesar de experts em outras, é tal que os diagnósticos neste campo e neste cenário comum devem sempre ser de consenso.

The value of high-resolution anoscopy in the diagnosis of anal cancer precursor lesions in hiv-positive patients

CONTEXT: Anal cancer, although a still rare disease, is being observed in ascending rates among some population segments known to be at risk for the development of the disease. Human papillomavirus (HPV) infection, immunodepression and anal intercourse are some factors associated with the development of the malignancy. Its similarities to cervical cancer have led to many studies aiming to establish guidelines for detecting and treating precursor lesions of anal cancer, with the goal of prevention. High-resolution anoscopy is routinely used for the diagnosis of anal cancer precursor lesions in many centers but the medical literature is still deficient concerning the role of this diagnostic modality. OBJECTIVES: To evaluate diagnostic validation and precision measures of high-resolution anoscopy in comparison to histopathological results of anal biopsies performed in HIV-positive patients treated at the Tropical Medicine Foundation of Amazonas, AM, Brazil. To observe any possible association between some risk factors for the development of anal cancer and the presence of anal squamous intraepithelial lesions. METHODS: A hundred and twenty-eight HIV-positive patients were submitted to anal canal cytological sampling for the detection of HPV infection by a PCR based method. High-resolution anoscopy was then performed after topical application of acetic acid 3% in the anal canal for 2 minutes. Eventual acetowhite lesions that were detected were recorded in respect to location, and classified by their tinctorial pattern, distribution aspect, relief, surface and vascular pattern. Biopsies of acetowhite lesions were performed under local anesthesia and the specimens sent to histopathological analysis. The patients were interviewed for the presence of anal cancer risk factors. RESULTS: The prevalences of anal HPV infection and of anal squamous intraepithelial lesions in the studied population were, respectively, 79% and 39.1%. High-resolution anoscopy showed sensibility of 90%, specificity of 19.23%, positive predictive value of 41.67%, negative predictive value of 75%, and a kappa coefficient of 0.076. From the analyzed lesions, high-grade squamous intraepithelial lesions was more frequently observed in association to dense (68%), flat (61%), smooth (61%), non-papillary (83%) and normal vascular pattern (70%) acetowhite lesions, while low-grade squamous intraepithelial lesions tended to be associated to dense (66%), flat-raised or raised (68%), granular (59%), non-papillary (62%) and normal vascular pattern (53%) acetowhite lesions. No statistical significance was observed as to the association of epidemiological characteristics and of most of the investigated anal cancer risk factors and presence of acetowhite lesions or anal squamous intraepithelial lesions. However, anal receptive sex and anal HPV infection were significantly associated to anal squamous intraepithelial lesions (P = 0.0493 and P = 0.006, respectively). CONCLUSION: High-resolution anoscopy demonstrated to be a sensitive, but not specific test for the detection of anal squamous intraepithelial lesions. Risk factors anal receptive sex and anal HPV infection were significantly associated to the presence of anal squamous intraepithelial lesions. Based on high-resolution anoscopy image data, acetowhite lesions relief and surface pattern were prone to distinguish between low-grade squamous intraepithelial lesions and high-grade squamous intraepithelial lesions.

Prevalence of anal intraepithelial neoplasia in women with genital neoplasia

BACKGROUND

Anal intraepithelial neoplasia is believed to be a precursor of anal cancer, and it appears to be related to high-risk human papillomavirus. Women with genital neoplasia have been shown to be at increased risk for anal cancer.

OBJECTIVE

The aim of this study is to determine the prevalence of anal intraepithelial neoplasia in women with genital neoplasia.

DESIGN

This is a cross-sectional study.

SETTING

This study took place at Hospital Nossa Senhora da Conceição, Porto Alegre, Brazil, from May 2008 to April 2010.

PATIENTS

Included in the study were 106 immunocompetent women with a histopathological diagnosis of genital neoplasia and 74 women without gynecologic neoplasia.

MAIN OUTCOME MEASURE

All women underwent high-resolution anoscopy with biopsies of acetowhite areas or abnormal vascular features such as punctation and mosaics for histopathological diagnosis of anal intraepithelial neoplasia.

RESULTS

: The overall prevalence of anal intraepithelial neoplasia was 6.6%. In women with genital neoplasia, the prevalence was 10.4% (95% CI, 5.6%-17.3%), whereas the prevalence was 1.4% (95% CI, 0.07%-6.5%) in women without genital neoplasia (P = .016). The prevalence ratio was 7.68 (95% CI, 1.01-58.21).

LIMITATION

Women with normal results on high-resolution anoscopy were not submitted to random biopsies for ethical reasons. Small lesions could be missed, and thus our findings might be underestimated.

CONCLUSION

The prevalence of anal intraepithelial neoplasia is higher in women with genital neoplasia.

Performance of p16INK4a immunocytochemistry as a marker of anal squamous intraepithelial lesions

BACKGROUND

Protein p16(INK4a) immunocytochemistry (ICCp16) has the potential to reveal lesions at risk of progression to anal cancer. This study examined measures of diagnostic validity of ICCp16 in HIV-positive patients treated at the Tropical Medicine Foundation of Amazonas in the coloproctology outpatient clinic.

METHODS

One hundred ninety HIV-positive patients were consecutively enrolled in 2007 and 2008. All patients underwent anal cytologic sampling to perform ICCp16 in conventional and GluCyte (Synermed International, Westfield, Indiana and S¸ao Paulo, Brazil) smears and also for genotyping of human papillomavirus (HPV). Patients were then subjected to anal biopsies monitored by high-resolution anoscopy. Hematoxylin-eosin and immunoperoxidase p16 (clone 6H12) stains were performed in slides with biopsied and cytological specimens, respectively. HPV genotyping on anal scrapings was performed by a polymerase-chain reaction (PCR)-based method. The immunochemical findings were compared with histopathological and PCR results in contingency tables and analyzed by nonparametric tests. Measures of diagnostic validity of ICCp16 were calculated. Statistical significance was set at P ≤ .5.

RESULTS

There was no statistically significant association between the immunochemical results (conventional or GluCyte smears) and histopathological or HPV genotyping findings (P > .05). In the best scenario, ICCp16 presented 31% sensitivity and 81% specificity for the diagnosis of anal squamous intraepithelial lesion (ASIL) and 30% and 66%, respectively, for the diagnosis of infection with high-risk HPV.

CONCLUSIONS

There was no association between ICCp16 results and histopathological findings nor between ICCp16 and HPV genotyping. ICCp16 showed poor sensitivity and moderate specificity for the diagnosis of ASIL or high-risk HPV.

Anal cancer precursor lesions in HIV-positive and HIV-negative patients seen at a tertiary health institution in Brazil

Purpose: To investigate the prevalence of anal squamous intraepithelial lesions (ASIL) or anal cancer in patients attended at the Tropical Medicine Foundation of Amazonas. Methods: 344 patients consecutively attended at the institution, in 2007/2008, were distributed in the following strata according to presence/abscense of at risk conditions for anal cancer: Group 1 _ HIV-positive men-who-have-sex-with-men (101); Group 2 _ HIV-positive females (49); Group 3 _ patients without any at risk condition for anal cancer (53); Group 4 _ HIV-positive heterosexual men (38); Group 5 _ HIV-negative patients, without anoreceptive sexual habits, but with other at risk conditions for anal cancer (45); Group 6 _ HIV-negative men-who-have-sex-with-men (26); and Group 7 _ HIV-negative anoreceptive females (32). The histopathological results of biopsies guided by high-resolution anoscopy were analyzed by frequentist and bayesian statistics in order to calculate the point-prevalence of ASIL/cancer and observe any eventual preponderance of one group over the other. Results: The point-prevalence of ASIL for all the patients studied was 93/344 (27%), the difference between HIV-positive and negative patients being statistically significant (38.3% versus 13.5%; p < 0.0001). The prevalence of ASIL for each one of the groups studied was: Group 1 = 49.5%, Group 2 = 28.6%, Group 3 = 3.8%, Group 4 = 21.1%, Group 5 = 11.1%, Group 6 = 30.8% and Group 7 = 18.8%. Standard residual analysis demonstrated that ASIL was significantly prevalent in patients of Group 1 and high-grade ASIL in patients of Group 2. The odds for ASIL of Group 1 was significantly higher in comparison to Groups 2, 3, 4, 5 and 7 (p < 0.03). The odds for ASIL of Groups 2, 4 and 6 were significantly higher in comparison to Group 3 (p < 0.03). Conclusions: In the patients studied, ASIL (low and/or high-grade) tended to be significantly more prevalent in HIV-positive patients. Nonetheless, HIV-negative anoreceptive patients also presented great probability to have anal cancer precursor lesions, mainly those of the male gender.

Management of anal squamous intraepithelial lesions

Anal squamous intraepithelial lesions include both low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL) and are caused by chronic infection with the human papillomavirus (HPV). The disease is increasing in both incidence and prevalence, especially among patients with the following risk factors: homosexual men, acquired or iatrogenic immunosuppression, and presence of other HPV-related diseases. Although the natural history of the disease is unknown, there is significant evidence that untreated HSIL progresses to squamous cell carcinoma in 11% of patients and in up to 50% of patients with extensive disease and immunosuppression. Anal cytology and reflex HPV DNA testing are used to screen for disease, particularly among patients with the aforementioned risk factors. Evaluation of the patient should include physical examination and high-resolution anoscopy (HRA) to evaluate for disease above and below the dentate line. Intervention is warranted and this can be achieved in many ways. The treatment option associated with the best outcomes is ablation directed with HRA, which can be performed in the office or in the operating room with minimal morbidity. This strategy is effective in patients with both low-volume and high-volume disease and is associated with a malignant progression rate of 0.4% in patients with treated HSIL.

Management of anal squamous intraepithelial lesions

Anal squamous intraepithelial lesions include both low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL) and are caused by chronic infection with the human papillomavirus (HPV). The disease is increasing in both incidence and prevalence, especially among patients with the following risk factors: homosexual men, acquired or iatrogenic immunosuppression, and presence of other HPV-related diseases. Although the natural history of the disease is unknown, there is significant evidence that untreated HSIL progresses to squamous cell carcinoma in 11% of patients and in up to 50% of patients with extensive disease and immunosuppression. Anal cytology and reflex HPV DNA testing are used to screen for disease, particularly among patients with the aforementioned risk factors. Evaluation of the patient should include physical examination and high-resolution anoscopy (HRA) to evaluate for disease above and below the dentate line. Intervention is warranted and this can be achieved in many ways. The treatment option associated with the best outcomes is ablation directed with HRA, which can be performed in the office or in the operating room with minimal morbidity. This strategy is effective in patients with both low-volume and high-volume disease and is associated with a malignant progression rate of 0.4% in patients with treated HSIL.

Diagnosis and management of anal cancer

During the past three decades, anal cancer has served as a paradigm for the successful application of chemoradiation to solid tumors. Since the early 1990s, the increasing incidence of anal cancer in homosexual men has highlighted the causative role of oncogenic human papilloma-virus infection. This review focuses on significant trends and developments in the management of patients with squamous cell carcinoma of the anal canal, emphasizing three major aspects of diagnosis and treatment: routine screening and eradication of premalignant lesions in high-risk individuals; outcome of chemoradiation therapy in HIV-positive individuals in the era of highly active antiretroviral therapy; and potential improvements in chemoradiation protocols through improved radiation delivery technique and the combination of mitomycin with cisplatin in current prospective randomized trials.