Anal colposcopy and the diagnosis of anal intraepithelial neoplasia in high-risk gynecologic patients

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.

Natural History of Anal HPV Infection in Women Treated for Cervical Intraepithelial Neoplasia

Women with high-grade squamous intraepithelial lesions/cervical intraepithelial neoplasia (HSIL/CIN) are at high risk of anal human papillomavirus HPV infection, and it has also been suggested that self-inoculation of the virus from the anal canal to the cervix could explain HPV recurrence in the cervix after treatment of HSIL/CIN. We aimed to evaluate the bidirectional interactions of HPV infection between these two anatomical sites. We evaluated 68 immunocompetent women undergoing excisional treatment for HSIL/CIN. Immediately before treatment, samples from the anus and the cervix were obtained (baseline anal and cervical HPV status). Cervical HPV clearance after treatment was defined as treatment success. The first follow-up control was scheduled 4-6 months after treatment for cervical and anal samples. High resolution anoscopy (HRA) was performed on patients with persistent anal HPV infections or abnormal anal cytology in the first control. Baseline anal HPV was positive in 42/68 (61.8%) of the women. Anal HPV infection persisted after treatment in 29/68 (42.6%) of the women. One-third of these women (10/29; 34.5%) had HSIL/anal intraepithelial neoplasia (AIN). Among women achieving treatment success, cervical HPV in the first control was positive in 34.6% and 17.6% of the patients with positive and negative baseline anal HPV infection, respectively (p = 0.306). In conclusion, patients with persisting anal HPV after HSIL/CIN treatment are at high risk of HSIL/AIN, suggesting that these women would benefit from anal exploration. The study also suggests that women with anal HPV infection treated for HSIL/CIN might be at higher risk of recurrent cervical HPV even after successful treatment.

Front-to-back & dabbing wiping behaviour post-toilet associated with anal neoplasia & HR-HPV carriage in women with previous HPV-mediated gynaecological neoplasia

BACKGROUND

Anal cancer is a human papillomavirus (HPV)-mediated neoplasia of the anal squamous epithelium. Anal cancer is much more common among women, particularly those with a previous high-grade gynaecological neoplasia.

METHODS

Cross-sectional study of women with a previous HPV-mediated gynaecological neoplasia in Tasmania, Australia. Women presenting for follow-up gynaecological care had anal swab samples taken for anal cytology by Hologic Liquid ThinPrep, followed by HPV genotyping. Women with abnormal anal cytology were invited for high-resolution anoscopy. Potential risk factors, including post-toilet wiping behaviours, were queried by questionnaire while clinical covariates were extracted from medical records. Covariates of anal outcomes evaluated by log-binomial and log-multinomial regression.

RESULTS

From 163 women enrolled in the study, 65 (39.9%) had abnormal cytology, with 46 (28.2%) being high-grade. Of the 50 women with abnormal anal cytology having high-resolution anoscopy, 32 (64.0%) had abnormal histology with 13 (26.0%) being high-grade. Of the 123 women tested for HR-HPV DNA, 48 (39.0%) had HR-HPV detected, the most common genotypes being 16 and 51 (14/123, 11.4% for both). In addition to some known anal cancer risk factors, we found front-to-back wiping was associated with significantly increased (Prevalence ratio (PR) range: 1.99-3.60) prevalence of cytological and histological abnormality and HR-HPV carriage/co-carriage, while dabbing post-toilet was significantly associated with decreased prevalences (PR range: 0.50-0.62).

CONCLUSIONS

Post-toilet wiping behaviours were significantly associated with the prevalence of anal cytological, histological and HR-HPV carriage outcomes. This suggests a biologically plausible mechanism for HR-HPV introduction and the higher frequencies of anal neoplasia in women.

High-resolution anoscopy: Unchartered territory for gastroenterologists?

High-resolution anoscopy (HRA) is a procedure where patients with an increased risk of anal cancer, like men who have sex with men, human immunodeficiency virus infected individuals, transplant patients and women with a history of lower genital tract neoplasia, with abnormal anal cytology results, are submitted to anal and perianal visualization under magnification. This will allow for a better detection of anal high-grade lesions that can be treated, in an effort to prevent anal cancer. Anal cancer screening follows the same principles that cervical cancer screening. During this procedure, an anoscope is inserted and a colposcope is used to examine systematically the squamocolumnar junction, the transformation zone and the perianal skin. Initially the observation is done with no staining and then with the application of acetic acid and Lugol’s iodine solution, allowing for better lesion identification and characterization. Any suspicious lesion seen should be carefully evaluated and biopsied. Without HRA only a small percentage of suspicious lesions are identified. High-grade lesions that are detected can be ablated under HRA. This is a challenging exam to perform, with a long learning curve and the number of clinicians performing it is limited, although the growing number of patients that need to been screened. Specific equipment is required, with these patients ideally been followed by a multidisciplinary team, in a reference centre. HRA remains unfamiliar for many gastroenterologists.

Colposcopic Characteristics and Lugol's Staining Differentiate Anal High-Grade and Low-Grade Squamous Intraepithelial Lesions During High Resolution Anoscopy

Background

Methods

Results

Conclusions

Anal intraepithelial neoplasia: review and recommendations for screening and management

Anal cancer is a rare malignancy of the distal gastrointestinal tract, often associated with human papillomavirus, the most common sexually transmitted infection worldwide. Currently available screening methods for anal intraepithelial neoplasia, a precursor for anal cancer, combine anal Papanicolaou cytology and high resolution anoscopy with biopsy of suspicious lesions. Significant barriers to establishing anal cancer screening programmes include the small number of healthcare professionals performing high resolution anoscopy and the lack of data showing that anal cancer screening can reduce morbidity and mortality related to anal carcinoma. Despite several controversies surrounding anal cancer screening, the rising incidence of this disease in some groups supports routine screening programmes in high-risk populations, especially in HIV-positive men who have sex with men.

This review outlines the epidemiology of anal intraepithelial neoplasia and anal cancer and summarizes issues related to the introduction of anal cancer screening programmes.

HPV and precancerous lesions of anal canal in women: systematic review

OBJECTIVE

The infection caused by human papillomavirus (HPV) in the anogenital area is considered the most common sexually transmitted infection in the world. Although anal cancer is relatively uncommon in the general population, there has been a significant increase in incidence in recent years. In this review, we focused on research on anal lesions in women.

METHOD

Research on HPV and precancerous lesions of the anal canal was examined by a systematic literature review in the Cochrane Centre of Brazil, where 1,734 publications were identified in the databases Scielo Brazil, Pubmed, Lilac, Medline, and Old Medline, for the period 1966 to 2010. We selected two papers, published in 1994 and 2009, based on the inclusion-exclusion criteria.

RESULTS

The first paper refers to the study of the anal canal in HIV-negative women with previous genital pathology and its relationship to the presence of HPV, and the other compares two groups of women who are HIV+ and HIV- and its relationship with anal disease and HPV.

CONCLUSION

The existence of previous genital neoplasia associated with HPV promotes the development of anal lesions, especially in younger patients, and a poor immune status contributes to the appearance of this pathologic finding.

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.

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

BACKGROUND

Renal graft recipients are one of the population groups known to be at high risk of developing anal cancer. This study investigated the presence of subclinical anal squamous intraepithelial lesions and the diagnostic ability of high-resolution anoscopy in detecting these lesions in renal graft recipients followed-up in Manaus.

METHODS

In a cross-sectional study, 50 renal graft recipients were interviewed and submitted to high-resolution anoscopy with biopsies of acetowhite lesions or of the anal transition zone mucosa when acetowhitening was absent. Considering the histopathological reports of the examined anal specimens as the gold standard, the diagnostic validation and precision measures of high-resolution anoscopy were calculated as well as the prevalence of anal squamous intraepithelial lesions in the studied population.

RESULTS

In 42 renal graft recipients with satisfactory histopathological readings, prevalence of anal squamous intraepithelial lesions or condyloma acuminatum (ASIL-ACU) was 23.81%. Sensitivity of high-resolution anoscopy was 100%; specificity, 65.63%; positive predictive value, 47.62%; negative predictive value, 100%; and kappa coefficient, 0.48.

CONCLUSIONS

With a prevalence of 23.81% of subclinical ASIL-ACU lesions, the studied renal graft recipients had all these lesions detected by high-resolution anoscopy, notwithstanding most anal transition zone acetowhitened biopsied areas did not reveal histopathological aspects of anal cancer precursor lesions or condyloma acuminatum. Therefore, greater experience with the diagnostic tool was felt necessary to enhance its positive predictive value, specificity and diagnostic precision.

Anal intraepithelial neoplasia and other neoplastic precursor lesions of the anal canal and perianal region

Anal cancer is rare and this helps to explain why anal pre-neoplastic conditions are poorly understood, especially with regard to their natural history and management. Anal intraepithelial neoplasia is closely linked to human papillomavirus infection and is particularly common in homosexuals and in immunosuppressed patients, especially those with HIV/AIDS. The high regression rates of low-grade anal intraepithelial neoplasia may simply reflect inconsistent pathologic reporting. Higher grades of anal intraepithelial neoplasia may remain static for long periods of time in immunocompetent patients, but those with HIV/AIDS show early and rapid malignant transformation. In general, most anal pre-neoplastic conditions are best diagnosed by biopsy and treated by surgical excision, although local recurrence is a problem. In anal Paget's disease, it is important to ascertain, at the time of diagnosis, whether it is due to a primary in-situ apocrine-type of neoplasia of the anus or if the disease is secondary to an invasive primary carcinoma of the rectum.

Neoplasia intraepitelial anal

Human papillomavirus (HPV) is responsible for anal condylomata, anal intraepithelial neoplasia (AIN) and anal squamous cell carcinoma. AIN is a premalignant condition that can progress to invasive carcinoma through different grades of severity of the disease called AIN I, AIN II and AIN III. This paper looks at the current definition, diagnostic methods and management of AIN. The incidence of AIN has increased significantly in the last decades. The groups at risk are mainly patients with infection with human immunodeficiency virus, immunossuppressed patients and patients affected by HPV related diseases (e.g., cervical cancer or anal condyloma). Accurate diagnosis of AIN lesions consists of accurate grading and disease extension. Low grade AIN (AIN I) or in extensive lesions, follow-up is advised to determine the possible evolution to anal squamous cell carcinoma. In cases of more severe and localized lesions (AIN II and AIN III), surgical resection should be considered if the predictive postoperative morbidity is low. Screening programs for AIN are not currently in place and there might be much effort to study the management of HPV in these patients.

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.

Colposcopic appearance of anal squamous intraepithelial lesions: relationship to histopathology

PURPOSE

The incidence of anal cancer is increased in men with a history of anal receptive intercourse. Analogous to cervical cancer, whose precursor is cervical high-grade squamous intraepithelial lesion (HSIL), anal cancer may be preceded by anal HSIL. Although not yet proven, detection, follow-up, and treatment of HSIL may prevent development of anal cancer. Cervical colposcopic methodology was used to describe anal lesions and to determine if HSIL could be distinguished from low-grade squamous intraepithelial lesion (LSIL).

METHODS

The colposcopic characteristics of 385 biopsied anal lesions were described and correlated with results of histopathology in a cohort of 121 human immunodeficiency virus-positive and 31 human immunodeficiency-negative homosexual/bisexual men with anal lesions followed as part of a longitudinal study of anal squamous intraepithelial lesions. Color, contour, surface, and vascular patterns of anal lesions were analyzed and correlated with histologic diagnosis.

RESULTS

Sixty-seven percent of biopsies showed LSIL and 26 percent showed HSIL. The positive predictive value for anal HSIL in lesions with characteristics typical of cervical LSIL was 7.7 percent (95 percent confidence interval, 1.8-14), whereas the positive predictive value for anal HSIL in lesions with characteristics typical of cervical HSIL was 49 percent (95 percent confidence interval, 40-58).

CONCLUSIONS

The colposcopic appearance of different grades of anal squamous intraepithelial lesions was similar to those described for the cervix. Incorporation of colposcopy into assessment of anal disease could aid in distinguishing anal LSIL from HSIL.

Treatment of anal intraepithelial neoplasia

The natural history and malignant potential of anal intraepithelial neoplasia (AIN) remain uncertain, making management decisions about such lesions difficult. The management of 70 patients with AIN is described. The majority of lesions encountered were low grade (AIN I and II; 43 of 70) and required no treatment, but eight invasive anal cancers associated with high-grade AIN occurred over the 4-year study period. Three were a result of apparent progression of high-grade lesions; three more invasive lesions were found in areas of AIN III on histological examination. Surgical excision was used to treat 27 patients with AIN III. Treatment of extensive lesions involving the perianal and anal canal epithelium circumferentially in six patients involved excision of the whole of this epithelium and application of split skin grafts.