Treatment of anal intraepithelial neoplasia

Structured Literature Review to Identify Human Papillomavirus's Natural History Parameters for Dynamic Population Models of Vaccine Impacts

Human papillomavirus (HPV) is a common sexually transmitted virus that can cause cervical cancer and other diseases. Dynamic transmission models (DTMs) have been developed to evaluate the health and economic impacts of HPV vaccination. These models typically include many parameters, such as natural history of the disease, transmission, demographic, behavioral, and screening. To ensure the accuracy of DTM projections, it is important to parameterize them with the best available evidence. This study aimed to identify and synthesize data needed to parametrize DTMs on the natural history of HPV infection and related diseases. Parameters describing data of interest were grouped by their anatomical location (genital warts, recurrent respiratory papillomatosis, and cervical, anal, vaginal, vulvar, head and neck, and penile cancers), and natural history (progression, regression, death, cure, recurrence, detection), and were identified through a systematic literature review (SLR) and complementary targeted literature reviews (TLRs). The extracted data were then synthesized by pooling parameter values across publications, and summarized using the range of values across studies reporting each parameter and the median value from the most relevant study. Data were extracted and synthesized from 223 studies identified in the SLR and TLRs. Parameters frequently reported pertained to cervical cancer outcomes, while data for other anatomical locations were less available. The synthesis of the data provides a large volume of parameter values to inform HPV DTMs, such as annual progression rates from cervical intraepithelial neoplasia (CIN) 1 to CIN 2+ (median of highest quality estimate 0.0836), CIN 2 to CIN 3+ (0.0418), carcinoma in situ (CIS) 2 to local cancer+ (0.0396), and regional to distant cancer (0.0474). Our findings suggest that while there is a large body of evidence on cervical cancer, parameter values featured substantial heterogeneity across studies, and further studies are needed to better parametrize the non-cervical components of HPV DTMs.

Practice parameters for the diagnosis and treatment of anal intraepithelial neoplasia (AIN) on behalf of the Italian Society of Colorectal Surgery (SICCR)

Squamous cell carcinoma (SCC) of the anus is a human papilloma virus (HPV) related malignancy that is preceded by anal intraepithelial neoplasia (AIN) making this cancer, at least theoretically, a preventable disease. In the past 10 years the diagnosis, management and nomenclature of AIN has dramatically changed. Increased life expectancy in human immunodeficiency virus (HIV) positive patients due to highly active antiretroviral therapy (HAART) has caused an increase in the incidence of SCC of the anus. While many experts recommend screening and treatment of anal high-grade squamous intraepithelial lesion (HSIL), there is no consensus on the optimal management these lesions. Therefore, there is a need to review the current evidence on diagnosis and treatment of AIN and formulate recommendations to guide management. Surgeons who are members of the Italian Society of Colorectal Surgery (SICCR) with a recognized interest in AIN were invited to contribute on various topics after a comprehensive literature search. Levels of evidence were classified using the Oxford Centre for Evidence-based Medicine of 2009 and the strength of recommendation was graded according to the United States (US) preventive services task force. These recommendations are among the few entirely dedicated only to the precursors of SCC of the anus and provide an evidence-based summary of the current knowledge about the management of AIN that will serve as a reference for clinicians involved in the treatment of patients at risk for anal cancer.

Expectant Management of High-Grade Anal Dysplasia in People with HIV: Long-term Data

BACKGROUND

Both ablation and expectant management of high-grade squamous intraepithelial lesions have been proposed. Expectant management would be reasonable if 1) the rate of high-grade squamous epithelial lesion progression to anal squamous cell carcinoma were low, and 2) anal squamous cell carcinoma arising under surveillance had a better prognosis than anal squamous cell carcinoma presenting without an identified precursor.

OBJECTIVE

This study aims to quantify aspects of high-grade squamous epithelial lesion/anal squamous cell carcinoma clinical evolution in a surgical practice.

DESIGN

This is a retrospective cohort study.

SETTINGS

This study was performed in 1 colorectal surgeon's practice over a 20-year period.

PATIENTS

Consecutive patients with high-grade squamous intraepithelial lesion and anal squamous cell carcinoma were included.

MAIN OUTCOME MEASURES

We looked at the rate and timing of progression to anal squamous cell carcinoma, and the stage, treatment, and outcome of anal squamous cell carcinoma. We reviewed a comparison group of HIV-positive patients presenting de novo with anal squamous cell carcinoma (no prior history of high-grade squamous intraepithelial lesion).

RESULTS

With consideration of only HIV-positive patients, 341 patients had a mean 5.6 years follow-up from high-grade squamous intraepithelial lesion diagnosis to the most recent documented anal examination. Twenty-four of these surveillance patients developed anal squamous cell carcinoma, yielding a progression rate of 1.3% per patient-year. Mean follow-up was 7.3 years from the initial cancer diagnosis to the most recent contact. Forty-seven patients who presented de novo with anal squamous cell carcinoma developed 74 lesions, with a mean follow-up of 5.7 years after initial diagnosis. This de novo group had higher anal squamous cell carcinoma-specific mortality (3% per patient-year vs 0.05%). Our study did not show a significantly higher rate of high stage (stage III or IV) at anal squamous cell carcinoma diagnosis in the de novo group in comparison with the surveillance group (25.5% vs 8.3% (p = 0.09)).

LIMITATIONS

This study was retrospective in nature and had a predominately male population.

CONCLUSIONS

The progression of untreated high-grade squamous intraepithelial lesion to anal squamous cell carcinoma approximates 1% per patient-year. Anal squamous cell carcinoma developing under surveillance tends to be of an earlier stage and to require fewer major interventions than anal squamous cell carcinoma presenting de novo. Cancer-specific mortality was lower for malignancies that developed under surveillance. We suggest that expectant management of patients with high-grade squamous intraepithelial lesion is a rational strategy for preventing anal cancer morbidity. See Video Abstract at http://links.lww.com/DCR/A699.

Initial Development and Content Validation of a Health-Related Symptom Index for Persons either Treated or Monitored for Anal High-Grade Squamous Intraepithelial Lesions

BACKGROUND

Anal cancer, caused by oncogenic types of human papillomavirus, is a growing problem in the United States. A key focus of anal cancer prevention has been screening for and treating precancerous high-grade squamous intraepithelial anal lesions (HSILs).

OBJECTIVES

To develop a health-related symptom index for HSIL using qualitative techniques because anal HSIL and its treatment may have a negative impact on health-related quality of life (HRQOL), and no HRQOL measure specific to this condition and treatment currently exists.

METHODS

Expert consultation was used to guide one-on-one concept elicitation interviews with participants to identify HRQOL aspects they attribute to their anal HSIL and its treatment. This resulted in a draft instrument, which was administered to an independent participant sample, where cognitive interview techniques assessed comprehension.

RESULTS

Eighteen anal HSIL-related concepts were identified by the expert panel. Across the 41 concept elicitation interviews, 23 items representing physical symptoms, physical impacts, and psychological symptoms were identified to comprise the initial measure, which was then evaluated during three rounds of cognitive interviews (n = 45). Several questionnaire aspects were refined on the basis of participant input, with three additional items added per expert/participant recommendation. One item was removed because of poor comprehension, resulting in a 25-item measure.

CONCLUSIONS

Using state-of-the-art qualitative methodology, we have established the content validity of this new instrument, the ANCHOR Anal HSIL Health-Related Symptom Index. Quantitative validation efforts are currently underway. The participant-driven process of developing this tool will facilitate a participant-centered evaluation of the impact on morbidity for treatment of anal HSIL or observation without treatment.

Brief Report: Radiofrequency Ablation Therapy for Anal Intraepithelial Neoplasia: Results From a Single-Center Prospective Pilot Study in HIV+ Participants

BACKGROUND

HIV-positive individuals have high incidence of anal high-grade squamous intraepithelial lesions (HSIL) at the squamocolumnar junction (SCJ), which can progress to cancer. Focal radiofrequency ablation (RFA) treats HSIL, but metachronous recurrence remains high and may be improved with circumferential treatment.

SETTING

The study was performed at a single center.

METHODS

This was a prospective trial of circumferential anal RFA using Barrx 60 RFA focal catheters in participants with ≥1 anal SCJ HSIL. The entire SCJ was ablated by RFA. Adverse events (AEs), symptoms, including pain, and quality of life were assessed. High-resolution anoscopy assessed recurrences at 3, 6, 9, and 12 months. Lesion site biopsies occurred at month 12. Recurrences were retreated with focal RFA.

RESULTS

Ten male participants (9 HIV+), with a median 2 HSILs (range 2-8) each, enrolled. Median T-cell count and viral load were 730 cells/mcL and 38 copies/mL. Median duration of RFA treatment was 6.5 (5-13) minutes. Lesion persistence occurred in 4 participants (3 at 3 months, 1 at 6 months). Recurrence at a new site occurred in 1 participant at 3 months. No lesion persisted after retreatment. All participants were HSIL free and completely healed by 12 months. Two device-related mild AEs occurred in 1 participant each (thrombosed external hemorrhoid and soft anal scar; both resolved). No serious AEs occurred.

CONCLUSION

Circumferential anal SCJ RFA produced total HSIL eradication with no more than 2 treatments. Circumferential RFA seems to be well tolerated with minimal pain and no serious AEs in HIV+ participants. CLINICALTRIALS.GOV:: NCT02189161.

Argon plasma coagulation treatment of anal high-grade squamous intraepithelial lesions in men who have sex with men living with HIV: results of a 2-year prospective pilot study

OBJECTIVES

Men who have sex with men (MSM) living with HIV are at high risk for anal high-grade squamous intraepithelial lesions (HSILs) and cancer. The best management of anal HSIL remains unclear. Our objective was to assess whether argon plasma coagulation (APC) could be safe, well tolerated and efficient to treat anal HSILs in MSM living with HIV.

METHODS

A prospective phase II, open-label, pilot study was conducted to evaluate APC to treat anal HSILs in 20 HIV-positive MSM. Participants were followed for 2 years after their first treatment.

RESULTS

Twenty men with persistent HSILs completed the 2-year study. Their baseline median CD4 count was 490 cells/μL and 85% had undetectable HIV viral loads. Overall, 65% (13/20) of participants were clear of HSILs at their 24-month visit. The initial response rates after the first, second and third APC treatments were 45%, 44% and 67%, respectively, but recurrences were common. The main side effect was pain during and within 1 week after the treatments. There were no long-term side effects, nor serious adverse events related to the procedure. Cost is a drawback.

CONCLUSIONS

APC can be used to treat anal HSILs in HIV-seropositive MSM, and requires repeated treatment because of a high recurrence rate. As successful treatment of human papillomavirus (HPV) infection or eradication of the anal transitional zone remains impossible, HSIL treatment is challenging and requires long-term follow-up.

A trial of radiofrequency ablation for anal intraepithelial neoplasia

PURPOSE

Radiofrequency ablation (RFA) effectively treats esophageal high-grade dysplasia, but its efficacy in treating anal canal high-grade squamous intraepithelial lesions (HSILs) is unsubstantiated. This prospective study assessed the safety and efficacy of applying hemi-circumferential RFA to anal canal HSIL.

METHODS

Twenty-one HIV-negative participants with HSIL occupying ≤ half the anal canal circumference were treated with hemi-circumferential anal canal RFA. Participants were assessed every 3 months for 12 months with high-resolution anoscopy; recurrence in the treatment zone was re-treated with focal RFA.

RESULTS

Twenty-one participants with a mean of 1.7 lesions (range 1-4) enrolled and completed the trial. Six (29 %) participants had recurrent HSIL within the treated hemi-circumference within 1 year. Four participants (19 %) had persistence of an index lesion at 3 months. One (2.9 %) index HSIL persisted again at 12 months. No participants had more than two RFA treatments. KM curve-predicted HSIL-free survival within the treatment zone at 1 year was 76 % (95 % CI 52-89 %). Comparing the first 7 and last 14 participants, the predicted 1-year HSIL-free survivals are 43 % (95 % CI 10-73 %) and 93 % (95 % CI 59-99 %), respectively (p = 0.008), suggesting a learning curve with the treating physician. Multivariable analysis showed decreased recurrence in the last 14 participants (HR 0.02; 95 % CI 0.001-0.63) while increasing BMI increased recurrence (HR 1.43, 95 % CI 1.01-2.01). No participants had device or procedure-related serious adverse events, anal stricture, or heavy bleeding.

CONCLUSIONS

Hemi-circumferential RFA yielded a high rate of anal HSIL eradication in HIV-negative patients at 1 year with minimal adverse events. Lesion persistence was probably related to incomplete initial ablation.

High-grade anal intraepithelial neoplasia: Progression to invasive cancer is not a certainty

BACKGROUND

The incidences of high-grade anal intraepithelial neoplasia (HSIL) and superficially invasive squamous cell carcinomas (SISCCA) related to human papillomavirus (HPV) have increased. These lesions can progress to invasive anal cancer. The aim of the study was to assess the clinical outcome with a special focus on the healing rate.

METHODS

Forty-six consecutive patients (M/F: 35/11; HIV+: 30) with histologically proven HSIL lesions (N=41) or SISCCA (N=5) were enrolled in a follow-up survey.

RESULTS

Of the 46 patients, 40 were treated by excision (n=9), electrocoagulation (n=13), topical treatment (n=2) or combined strategies (n=16). After a mean follow-up of 35 (27-43) months, only one patient progressed to an invasive cancer. Regression and healing were observed in 14 (30%) and 15 (33%) patients. The cumulative probabilities of healing were 14%, 49% and 74% after 1, 3 and 5 years. None of the current smokers healed. Heterosexual patients, sexual abstinence, patients older than 44 years old, non-smokers, patients without any past history of condyloma and those with less than 2 high-risk HPVs at baseline were more likely to heal.

CONCLUSION

Progression to invasive cancer is a rare event. Large, prospective cohort studies are needed to plan coherent strategies for both follow-up and treatment.

Current treatment options for management of anal intraepithelial neoplasia

Anal squamous cell cancer is an uncommon malignancy caused by infection with oncogenic strains of Human papilloma virus. Anal cancer is much more common in immunocompromised persons, including those infected with Human immunodeficiency virus. High-grade anal intraepithelial neoplasia (HGAIN), the precursor of anal cancer, is identified by clinicians providing care for patients with anorectal disease, and is increasingly being identified during screening of immunosuppressed patients for anal dysplasia. The traditional treatment for HGAIN has been excision of macroscopic disease with margins. This approach is effective for patients with small unifocal HGAIN lesions. Patients with extensive multifocal HGAIN frequently have recurrence of HGAIN after excision, and may have postoperative complications of anal stenosis or fecal incontinence. This led to the suggestion by some that treatment for HGAIN should be delayed until patients developed anal cancer. Alternative approaches in identification and treatment have been developed to treat patients with multifocal or extensive HGAIN lesions. High-resolution anoscopy combines magnification with anoscopy and is being used to identify HGAIN and determine treatment margins. HGAIN can then be ablated with a number of modalities, including infrared coagulation, CO2 laser, and electrocautery. These methods for HGAIN ablation can be performed with local anesthesia on outpatients and are relatively well tolerated. High-resolution anoscopy-directed HGAIN ablation is evolving into a standard approach for initial treatment and then subsequent monitoring of a disease which should be expected to be recurrent. Another treatment approach for HGAIN is topical treatment, principally with 5-fluorouracil or imiquimod. Topical therapies have the advantage of being nonsurgical and are well suited for treating widespread multifocal disease. Topical treatments have the disadvantage of requiring extended treatment courses and causing a symptomatic inflammatory response. Successful treatment requires adherence to a regime that is uncomfortable at best and at worst painful. Topical treatments can be successful in motivated adherent patients willing to accept these side effects.

Long-term effectiveness of infrared coagulation for the treatment of anal intraepithelial neoplasia grades 2 and 3 in HIV-infected men and women

AIMS

To assess the effectiveness and safety of infrared coagulation (IRC) for the ablation of anal intraepithelial neoplasia (AIN) and to provide data on the prevalence of AIN in HIV-infected patients.

PATIENTS AND METHODS

We performed a single-center, retrospective cohort study based on data collected from a prospectively compiled database of outpatients attended in the Clinical-Proctology-HIV-Unit (first visit). The effectiveness (normal anal cytology after 12 months of IRC) and safety of IRC were estimated.

RESULTS

Between January 2005 and December 2011, a total of 69 (5%) patients with biopsy-proven AIN-2 or AIN-3 from among 1518 patients (1310 men; 208 women) were treated with IRC. The prevalence of cytological abnormalities was 49.5% [751/1518; (atypical squamous cells of unknown significance, 14%; low-grade squamous intraepithelial lesions, 27.5%; high-grade squamous intraepithelial lesions, 8%)]. High-resolution anoscopy revealed intra-anal condylomata in 31% of patients (236/751), nonvisualized lesions in 30% (227/751), and visualized lesions (from which biopsy specimens were taken) in 38% (288/751). The histological diagnosis was: AIN-1, 52% (151/288); AIN-2, 15% (44/288); AIN-3, 9% (25/288); normal, 19% (56/288); and nonevaluable, 4% (12/288). IRC was applied in-office in 66 patients (three refused to undergo treatment). At 12 months, all patients (n = 56) had a normal anal cytology result. Seven (13%) patients had biopsy-proven recurrence [mean (range) time-to-recurrence, 30 (18-43) months]. High-risk-human papilloma virus (HPV) infection was detected in all anal lesions (HPV-16 was the most common genotype). Agreement between cytological and histological results was poor.

CONCLUSION

A high prevalence of AIN was found in both HIV-infected men and HIV-infected women. Although randomized clinical trials are lacking, IRC ablation of AIN-2 and AIN-3 lesions without concomitant condylomata could help prevent anal squamous cell carcinoma.

Long-term follow-up of infrared coagulator ablation of anal high-grade dysplasia in men who have sex with men

BACKGROUND

We previously reported on infrared coagulator ablation of anal high-grade intraepithelial squamous lesions in HIV-positive and HIV-negative men who have sex with men (MSM) with a median follow-up of 1.5 years.

OBJECTIVE

We sought to determine high-grade intraepithelial squamous lesion recurrence rates after long-term follow-up for infrared coagulator ablation, and whether patients progressed to invasive cancer.

DESIGN

: This study investigated a retrospective cohort.

SETTING

This study was set in an office-based practice.

PATIENTS

The patients evaluated were MSM who underwent at least 1 infrared coagulator anal high-grade intraepithelial squamous lesion ablation between 1999 and 2005 with at least 1-year additional follow-up.

INTERVENTION

Infrared coagulator ablation had been performed.

MAIN OUTCOME MEASUREMENT

The primary outcomes measured were high-grade intraepithelial squamous lesion recurrence and progression to anal squamous-cell carcinoma.

RESULTS

Ninety-six MSM were included (44 HIV-positive) with a median follow-up of 48 and 69 months in HIV-negative and HIV-positive MSM. Thiry-five percent of HIV-positive and 31% of HIV-negative subjects from the original cohort were lost to follow-up. In HIV-negative MSM, 32 (62%) had a recurrence in a mean of 14 months. Recurrence rates after the second and third treatments were 48% and 57%. In HIV-positive MSM, 40 (91%) had a recurrence in a mean of 17 months. Recurrence rates after the second, third, and fourth infrared coagulator ablations were 63%, 85%, and 47%. After the first ablation, HIV-positive MSM were 1.9 times more likely to have a recurrence than HIV-negative MSM (P = .009). One year after the first ablation, 61% of HIV-positive MSM had recurrent high-grade intraepithelial squamous lesions in comparison with 38% of HIV-negative MSM. One year after the second ablation, 49% of HIV-positive MSM had recurrent high-grade intraepithelial squamous lesions in comparison with 28% of HIV-negative MSM. In HIV-negative and HIV-positive MSM, the probability of curing an individual lesion after first ablation was 80% and 67%. Most recurrence was due to the development of metachronous lesions occurring in 82% and 52% of HIV-positive and HIV-negative subjects after their first infrared coagulator treatment. The mean number of recurrent lesions for both HIV-positive and HIV-negative MSM was never >2. No MSM developed squamous-cell carcinoma, and there were no serious adverse events. At last visit, 82% of HIV-positive MSM and 90% of HIV-negative MSM were high-grade intraepithelial squamous lesion free.

LIMITATIONS

This was a retrospective, observational study with significant loss to follow-up.

CONCLUSIONS

Infrared coagulator ablation is an effective treatment for high-grade intraepithelial squamous lesions, and no patients progressed to cancer. HIV-positive patients are significantly more likely to have a recurrence, and recurrence occurred more rapidly in these patients. Continued follow-up is important.

Anal intraepithelial neoplasia and anal cancer in dermatological practice

Anal intraepithelial neoplasia is considered to be a precursor lesion of invasive anal cancer. It is now increasingly recognized in high-risk groups, such as men who have sex with men and HIV-infected patients. Human papillomaviruses are considered to be an important aetiological agent in both anal intraepithelial neoplasia and anal cancer. Dermatologists are likely to encounter these conditions among the differential diagnoses to be considered in high-risk patients presenting with perianal and anal lesions. Anal cancer rates are also increasing among the HIV-infected and HIV-non-infected population. The successful treatment of anal intraepithelial neoplasia may reduce the risk of subsequent development of anal cancer. However, current therapies for anal intraepithelial neoplasia may be associated with treatment-related morbidity and are not well validated. It is currently not proven that they reduce the likelihood of the development of anal cancer. Nevertheless, screening for anal intraepithelial neoplasia is being advocated for high-risk groups and may become standard dermatological care for these patients. In view of recent developments in the understanding of this condition, this article reviews the current understanding of anal intraepithelial neoplasia and its treatment from a dermatological perspective.

Infrared coagulator ablation of high-grade anal squamous intraepithelial lesions in HIV-negative males who have sex with males

PURPOSE

The incidence of anal squamous carcinoma in males who have sex with males is rising. We reported that infrared coagulation of high-grade squamous intraepithelial lesions in HIV-positive males who have sex with males yielded a recurrence rate after the first ablation of 65 percent and 58 percent after a second ablation. The cure rate of an individual lesion was 72 percent. We endeavored to determine whether this technique demonstrates improved results in HIV-negative males who have sex with males.

METHODS

We performed a retrospective review of medical records on HIV-negative males who have sex with males who had infrared coagulation ablation of anal high-grade squamous intraepithelial lesions. Patients had at least six months' follow-up with cytology, high-resolution anoscopy, and biopsy. Recurrent high-grade squamous intraepithelial lesions were retreated.

RESULTS

Seventy-five patients were enrolled, with a median age of 36 years, and 113 lesions were treated. Forty patients (53 percent) developed a recurrence in a median time of 238 days and 35 patients (47 percent) were disease free for a median of 516 days. When patients were treated a second or third time, recurrence rates dropped to 28 and 0 percent, respectively. The probability of successfully treating an individual lesion at first infrared coagulation was 81 percent and 93 percent when retreated. HIV-positive patients were twice as likely to have lesions persist and 1.7 times more likely to develop a recurrent high-grade squamous intraepithelial lesion. No patient developed squamous-cell carcinoma, anal stenosis, or had a serious complication.

CONCLUSIONS

Infrared coagulation is a safe and effective office-based procedure for treating anal high-grade squamous intraepithelial lesions. Although recurrence was high after the first infrared coagulation, repeated treatment led to resolution of high-grade squamous intraepithelial lesions. Treatment success with infrared coagulation is significantly superior in HIV-negative patients compared with HIV-positive patients.

Malignant transformation of high-grade anal intraepithelial neoplasia

BACKGROUND

The natural history of anal intraepithelial neoplasia (AIN) is uncertain. This makes management problematic as treatment options to eradicate the condition carry morbidity. The authors report their 10-year experience with conservative management of this condition, highlighting the lessons learnt.

METHODS

All patients were diagnosed with high-grade AIN (AIN III) between 1994 and 2003. Diagnosis was by full-thickness biopsy and histopathological examination. Excision of localized lesions was undertaken, and all patients underwent follow-up every 6 months. Prospective data were collected regarding recurrence, postoperative complications and progression to invasive carcinoma.

RESULTS

Thirty-five patients were followed for a median of 63 (range 14-120) months. Excision of localized high-grade AIN was carried out in 28 patients with minimal morbidity. Six patients were systemically immunosuppressed at diagnosis, all of whom had multifocal perianal lesions. Three immunosuppressed patients developed invasive anal squamous carcinoma during follow-up. By contrast, no invasive carcinomas were identified among immunocompetent patients with either localized or multifocal perianal disease.

CONCLUSION

AIN III appears to have a relatively low potential for malignant transformation in the immunocompetent patient. However, immunosuppressed patients are more likely to have extensive AIN III and a greater risk of malignant change.

Anal intraepithelial neoplasia

Background

Anal intraepithelial neoplasia (AIN) is believed to be a precursor of anal squamous cell cancer and its incidence is rising in high-risk groups, particularly those infected with the human immunodeficiency virus (HIV). The natural history of AIN is unclear and management strategies are lacking.

Methods

This review is based on a literature search (Medline and PubMed) with manual cross-referencing of all articles related to AIN.

Results and conclusions

The aetiology of AIN is intricately linked with human papilloma viruses. The pathological processes involved in the progression of AIN are becoming clearer but the natural history, particularly the rate of progression to invasive cancer, remains unknown. There is no standard management for AIN and this is mainly due to difficulties in both diagnosis and treatment. A variety of treatment options have been tried with varying success. Surgery is associated with significant recurrence, particularly in HIV-positive patients. Non surgical approaches with imiquimod, photodynamic therapy and vaccination are appealing, and further work is required. Long-term follow-up of these patients is essential until the natural history of AIN becomes clearer.

Angiogenesis in anal warts, anal intraepithelial neoplasia and anal squamous cell carcinoma

INTRODUCTION

Most cases of anal carcinoma seem to develop from high grade anal intraepithelial neoplasia (AIN) caused by persistent anal warts. Similar pre-invasive epithelial genital lesions (e.g. those of the cervix and vulva) have been shown to be associated with increased angiogenesis. In this study we examined biopsies of anal lesions ranging from warts to invasive anal carcinoma, with the aim of assessing the degree of angiogenesis in pre-invasive anal lesions.

METHOD

Samples from 70 patients (51 male) who had undergone excision biopsy or resection of anal wart lesions (20), low grade AIN (12), high grade AIN (27) and anal squamous cell carcinoma (SCC) (11) were studied. Samples (6) from normal HIV-anal skin were used as controls. The samples were stained for von Willebrand factor, a specific marker of endothelial cells. Angiogenesis was measured by microvessel density (MVD) analysis, quantifying the microvessels in the stroma adjacent to the epithelial lesion.

RESULTS

There was a statistically significant (P < 0.001) progressive increase in MVD between low grade AIN, high grade AIN and anal SCC. The difference in MVD between normal skin, warts and low grade AIN was not statistically significant.

CONCLUSION

There are progressive abnormal patterns of angiogenesis in highly dysplastic lesions, similar to those found in cervical and vulvar pathology. These findings may have biological, prognostic and therapeutic implications.

Therapeutic vaccination for the treatment of mucosotropic human papillomavirus-associated disease

There is a high prevalence of diseases caused by human papillomavirus (HPV) infection. Unfortunately, current treatments are inadequate. However, because there is evidence to support a role for the immune system in host defence against this virus, an immunotherapeutic approach is warranted. The existing immunotherapies are not completely effective, nor are they durable. In addition, natural history studies associated with spontaneous regression have provided little guidance to the design of successful interventions. This state of knowledge has encouraged efforts towards the development of novel immunotherapeutic strategies. Successful preclinical studies of therapeutic vaccine candidates have led to clinical studies for a variety of HPV-associated indications, such as anogenital warts and cervical and anal intraepithelial neoplasia. Immunisation approaches such as adjuvanted peptides, virus-like particles and fusion constructs are discussed. Specifically, chimaeric molecules comprised of mycobacterial heat-shock proteins (Hsps) and HPV16 E7 appear promising.

Radical excision of multifocal anal intraepithelial neoplasia: report of a case

PURPOSE

The aim of this study was to describe the technique of radical excision of multifocal anal intraepithelial neoplasia and discuss controversial issues surrounding the management of this condition.

METHOD

We describe the case of a 31-year-old female with previous vulval warts, vulval squamous carcinoma, and recent immunosuppression who had widespread anal intraepithelial neoplasia excised, and the resulting defect was split-skin grafted, including the anal canal.

RESULTS

Excision and split-skin grafting was successful in removing the disease and left a satisfactory cosmetic and functional result.

CONCLUSION

Diffuse, high-grade, anal intraepithelial neoplasia is rare. Excision of these lesions remains controversial but may be the best option.

Treatment of grade 3 anal intraepithelial neoplasia by complete anal mucosal excision without fecal diversion: report of a case

PURPOSE

The aim of this study was to remove completely the risk of malignant transformation without permanent or temporary fecal diversion in a patient with extensive anal intraepithelial neoplasia.

METHODS

All anal canal mucosa and the lowest 1.5 cm of rectal mucosa were excised and the adjacent rectal mucosa and submucosa advanced to the anal verge skin.

RESULTS

The patient achieved normal continence within a month after the operation. Multiple anal canal biopsies at 12 months after the operation revealed normal rectal mucosa.

CONCLUSIONS

Total anal mucosal excision offers a relatively simple means of removing the malignant risk of anal intraepithelial neoplasia without fecal diversion in selected patients.

Outcome after surgical resection for high-grade anal intraepithelial neoplasia (Bowen's disease)

BACKGROUND

High-grade anal intraepithelial neoplasia (Bowen's disease) may predispose to anal carcinoma. Treatment options include surgical resection but effectiveness remains uncertain. This paper reports long-term follow-up of patients with high-grade anal intraepithelial neoplasia treated by surgical resection.

METHODS

Between 1989 and 1996, 46 patients were identified with high-grade anal intraepithelial neoplasia. Thirty-four underwent local excision of all macroscopically abnormal disease and the resulting defect was left open, closed primarily or skin grafted. Regular follow-up subsequently included anoscopy and biopsy of any suspicious lesions.

RESULTS

Median follow-up was 41 (range 12-104) months. Total excision was difficult; 19 patients had histological evidence of incomplete excision at the time of initial resection. Some 12 of 19 had histo-logically proven recurrent high-grade intraepithelial neoplasia within 1 year. Even with microscopically complete excision two of 15 patients subsequently developed recurrent high-grade intraepithelial neoplasia at 6 and 32 months after operation. No patient developed carcinoma but five had complica-tions of anal stenosis or faecal incontinence.

CONCLUSION

Although no definite recommendations can be made for the treatment of high-grade anal intraepithelial neoplasia, these results illustrate some potential drawbacks of surgical excision with a high potential for incomplete excision and persistent disease, even after complete excision in some patients, and a high morbidity rate.

Perianal Bowen's disease and anal intraepithelial neoplasia: review of the literature

PURPOSE

The aim of this study was to review the literature with regard to perianal Bowen's disease and anal intraepithelial neoplasia.

METHODS

A literature review was conducted from 1960 to 1999 using MEDLINE.

RESULTS

Perianal Bowen's disease and anal intraepithelial neoplasia are precursors to squamous carcinoma of the anus. They are analogous to and are associated with cervical and vulvar intraepithelial neoplasia, and have human papillomavirus as a common cause. Biopsy and histopathologic examination is required for diagnosis and to distinguish other perianal dermatoses. Treatment options range from aggressive wide local excision of all disease with negative margins to observation alone for microscopic lesions not visible to the naked eye. The disease has a proclivity for recurrence and recalcitrance.

CONCLUSIONS

Most surgeons caring for patients with perianal Bowen's disease and high-grade anal epithelial neoplasia use wide local excision, with an effort to obtain disease-free margins. Some authors have reported the advantages of ablative procedures such as laser ablation and cryotherapy. Microscopic disease found serendipitously in hemorrhoidectomy specimens can probably be treated conservatively with serial examinations alone. There is a lack of controlled data supporting an optimal treatment strategy. A multicenter controlled study comparing wide local excision with ablative procedures may be warranted.