Anal Squamous Cell Cancer Research Articles

Feasibility and Outcome of Routine Use of Concurrent Chemoradiation in HIV-positive Patients With Squamous Cell Anal Cancer.

Clinical concerns about hematologic toxicities in human immunodeficiency virus (HIV)+ patients with squamous cell anal cancer (SCAC) may lead to de-escalation of treatment intensity. The objective of this study is to evaluate clinical outcomes including toxicity following standard concurrent curative-intent chemoradiation for HIV+ and HIV- patients with SCAC. Among 97 evaluable patients treated between 2009 and 2016 (median age 52.2 y), 43 (44.3%) were HIV+ and 54 (55.7%) HIV-. The majority of the radiation was delivered using intensity-modulated radiation therapy and chemotherapy consisting primarily (93%) of 5-fluorouracil and mitomycin C. Clinical outcomes assessed included toxicity, locoregional control (LRC), distant metastasis (DM), progression-free survival (PFS), colostomy-free survival (CFS), overall survival (OS), and cause-specific survival (CSS). With a median follow-up of 45 months, HIV+ patients exhibited a trend toward reduced OS compared with HIV- patients (4 y OS 61.2% vs. 78.3%; HR 2.09; 95% CI, 0.97-4.52; P=0.055) on univariable analysis, but HIV status was not significant after adjusting for additional parameters on multivariable analysis. Toxicity rates, LRC, CFS, PFS, freedom from DM, and CSS were similar between the 2 cohorts. On multivariable analysis, tumor size >5 cm impacted all clinical outcomes (trend for LRC) except CFS. Radiation treatment extension beyond 7 days was found to negatively impact LRC and CSS. Male sex was associated with worse CFS. Radiation therapy with concurrent 5-fluorouracil and mitomycin C chemotherapy is reasonably well-tolerated as curative treatment for HIV+ patients with SCAC, and no significant difference in outcomes was noted relative to HIV- patients.

The importance of anal cancer screening and high-resolution anoscopy to gastroenterology practice.

Although human papillomavirus (HPV)-related anal squamous cell cancer (ASCC) is rare, its incidence has been rising and in high-risk populations exceeds the incidence of cancers for which screening programs are implemented. Therefore, targeted screening techniques are being evaluated with high-resolution anoscopy (HRA) as the current gold standard because of its ability to detect anal intraepithelial dysplasia (AIN) and premalignant high-grade squamous intraepithelial lesions (HSILs). However, a scarcity of trained providers presents a barrier to screening. ASCC incidence is rising especially in elderly women and young black men. Premalignant HSIL may not only progress to ASCC but also regress. Biomarkers such as HPV type, p16 immunostaining and DNA methylation markers may emerge as predictors of disease progression.HRA with acetic acid and Lugol's iodine staining can be used to detect HSIL and ASCC. Recent studies suggest that anal cancer screening may have an impact on the stage of ASCC at diagnosis and the incidence of anal cancer.The Anal Cancer HSIL Outcomes Research (ANCHOR) study is underway to determine whether treating HSIL effects ASCC incidence. Although there are no consensus screening guidelines for anal cancer, it is reasonable to screen high-risk populations with physical examination, anal cytology and HRA. Gastroenterologists can support anal cancer screening programmes through identifying patients at risk, performing noninvasive screening and considering to incorporate endoscopic techniques to examine the anal canal. VIDEO ABSTRACT: http://links.lww.com/COG/A32.

Refusal of Chemoradiation Therapy for Anal Squamous Cell Cancer

Refusal of Chemoradiation Therapy for Anal Squamous Cell Cancer

Characterization of sociodemographic and clinicopathological features and associated outcomes of patients (Pts) with anal squamous cell cancer (ASCC): Analysis of 44,084 pts in the National Cancer Database (NCDB).

4052 Background: ASCC incidence is rising. There are limited data on the relationships between sociodemographic & clinicopathological features and outcomes of ASCC pts. Methods: Pts diagnosed with ASCC between 2004 and 2016 were retrospectively reviewed. Data obtained from the NCDB were used to examine the impact of sociodemographic status on clinicopathological features and outcomes. Pts were categorized based on low (median < $38,000) or high (≥$68,000) income and low ( > 21% with no high school diploma) or high ( < 7% with no high school diploma) education areas based on zip code at time of diagnosis. Logistic regression and chi-square were used to examine differences between groups. Results: In total, 44,084 pts with ASCC were identified: median age, 59 yrs, 86% white; 11% black; 64% female. Most pts (84%) resided in metro areas; 29.7% vs 19.8% lived in high vs low income areas; 22.9% vs 17.8% lived in high vs low education areas. Seven percent were uninsured, 50% had government (Gov), and 43% had private insurance. Male gender (HR 1.62, CI 1.41-1.85, p < 0.001), low income area (HR 1.28, CI 1.19-1.37, p = 0.014), and insurance status (Gov, HR 1.55, CI 1.32-1.82, p < 0.001 and uninsured, HR 1.37, CI 1.37-1.85, p = 0.039) were associated with a higher risk of death. After adjusting for age, sex, race, stage, grade, insurance status, and comorbidity, pts from low income/education (n = 6695) vs high income/education (n = 4316) areas had a 33 % increased risk of death (HR: 1.33, p < 0.001). Pts with stage IV ASCC in the low income/education (n = 227) vs high income/education (n = 295) groups had worse overall survival (mOS, 1.4 vs 1.9 yrs, p < 0.020). Of the 44,084 pts, 5461 (12.4%) had confirmed HPV status. Of these, 2658 (48.7%) were HPV+ (high risk subtypes) and 2803 (51.3%) were HPV-. Compared to the HPV- pts, HPV+ pts were more likely to be women (71.8% vs 67.8%, p = 0.001), have stage 3 (38.1% vs 33.6%) or 4 (7.9% vs 5.9%, p < 0.001) cancer, and have poorly differentiated (29.5% vs 25.6%, p < 0.001) tumors. There were no significant differences in race, education, income, metro area, insurance status, or comorbidity between the HPV+ and HPV- pts. Moreover, HPV status did not impact OS (HR 0.92, CI 0.81-1.04, p = 0.195). Conclusions: HPV status was not correlated to income, education or insurance status, and did not impact OS in ASCC pts. Male gender and insurance status were associated with increased risk of death. Pts living in low income and low education areas were associated with worse survival.

Socioeconomic status based on race in early-stage anal squamous cell carcinoma undergoing locoregional therapy.

4056 Background: Anal Squamous Cell Cancer (ASCC) is a highly curable cancer. Underserved and vulnerable populations are particularly at risk of developing this disease. We aimed to study racial disparities and overall survival (OS) in patients with ASCC who received radiation therapy (RT) or chemo-RT (CRT) using the National Cancer Database. Methods: We identified adult patients with early-stage (stage I-II) ASCC diagnosed between 2004-2016 who underwent RT or CRT. We compared the clinical and treatment characteristics of white and black patients. The chi-square test was used for categorical variables. Kaplan-Meier and Cox regression method performed for survival analyses. We used 1:1 nearest neighbor propensity score matching to eliminate selection bias. Results: A total of 10,014 patients; 90.2% were white and 9.8% were black. White patients were more likely to be female, older age, have higher rate high-school education, private insurance, higher income, and travel a longer distance (all p < .001). Black patients were more likely to be higher comorbidity score and be treated at an academic/research facility. White patients had a higher rate of CRT and significantly better overall survival (OS) as compared to black patients (5-year survival 76% vs. 70%, p < .001) which persisted after propensity score matching (5-year survival 76% vs. 70%, p = .002). This difference continued after adjusting for clinically important factors, including HPV status (unmatched p < .03, matched p = .008). In the patients who received CRT, white patients were associated with improved OS versus black patients (unmatched 77% vs. 71%, p < .001; matched 77% vs. 71%, p = .011), and even after multivariate Cox analysis (unmatched p < .001; matched .014) (Table). Conclusions: White patients had significantly better OS as compared to black patients with early-stage ASCC as well as in the patients who received CRT. White patients were associated with high education level, higher income, and private insurance. The rate of HPV positive was similar among groups. Further investigations are needed to enlighten these disparities and target the increase education of the population at risk. [Table: see text]

Factors Associated With Chemoradiation Therapy Interruption and Noncompletion Among Patients With Squamous Cell Anal Carcinoma

Definitive chemoradiation for anal cancer is effective but may be associated with toxic effects, and some patients may not be able to complete the planned treatment. Identifying factors associated with treatment interruption and noncompletion is important to target quality improvement efforts. To identify rates of chemoradiation treatment interruption or noncompletion and factors associated with this among patients with anal cancer treated in routine clinical practice. In this population-based, retrospective cohort study, the Ontario Cancer Registry was used to identify all incident cases of squamous cell anal cancer treated with curative-intent radiation from 2007 to 2015 in Ontario, Canada. Final analysis of data was performed on August 9, 2019. Curative-intent radiation therapy. Treatment interruption was defined as more than 7 days between fractions of radiation. Radiation completion was defined as receipt of 45 Gy or more and 25 fractions of radiation. Chemoradiation completion was defined as radiation completion and 2 doses of combination chemotherapy. Associations between patient factors and treatment interruption and noncompletion were estimated with log-binomial models. Cox proportional hazard models were used to estimate the association of treatment interruption or noncompletion with all-cause death, cancer-specific death, and the combined outcome of colostomy or death. Overall, 1125 patients with stage I-III anal cancer were treated with curative-intent radiation. Treatment interruptions occurred in 262 (23%). Radiation and chemoradiation noncompletion occurred in 199 (18%) and 280 (25%), respectively. No associations were found to correlate with an increased risk of treatment interruption. Patients older than 70 years were less likely to complete chemoradiation (risk ratio [RR], 0.60; 95% CI, 0.52-0.70), compared with those younger than 50 years. Patients with a higher number of comorbidities were also less likely to complete chemoradiation (RR, 0.70; 95% CI, 0.51-0.95). Patients who did not complete chemoradiation had a higher risk of requiring salvage abdominoperineal resection (RR, 1.54; 95% CI, 1.03, 2.31), overall death (hazard ratio [HR], 1.54; 95% CI, 1.23-1.92), cancer-specific death (HR, 1.59; 95% CI, 1.14-2.22), and colostomy or death (HR, 1.80; 95% CI: 1.10-2.93). Treatment interruptions longer than 7 days were not associated with death. Many patients undergoing curative-intent chemoradiation for anal cancer experienced treatment interruption or noncompletion. Quality improvement initiatives to optimize treatment continuity and completion are needed.

Distinguishing between HPV-Associated Metastatic Anal Squamous Cell Cancer and HPV-Associated Oropharyngeal Cancer

The histology and immunohistochemistry (IHC) of primary and metastatic diseases from a human papilloma virus- (HPV-) related anal squamous carcinoma (ASCC) would typically demonstrate the same histology as an HPV-related oropharyngeal squamous carcinoma (OPSCC). However, determining whether a site of squamous cell carcinoma represents distant metastatic ASCC versus a metastatic HPV-related metastasis from an OPSCC to a regional lymph node carries profound prognostic and therapeutic implications. A patient with a history of locally advanced ASCC treated with standard concurrent radiation therapy and chemotherapy in 2015 is described. In 2018, an enlarged supraclavicular lymph node was excised demonstrating squamous cell carcinoma and radiographic staging revealed no other areas suspicious for malignancy. Direct laryngoscopy with operating telescope and biopsies demonstrated squamous cell carcinoma at the tongue base. Described here are assays that might be considered in distinguishing between whether a focus distant from a previously identified ASCC represents metastatic disease or instead a separate primary HPV-related cancer.

Sarcopenia is associated with worse overall survival in patients with anal squamous cell cancer

Sarcopenia is associated with poor long-term outcomes in many gastrointestinal cancers, but its role in anal squamous cell carcinoma (ASCC) is not defined. We hypothesized that patients with sarcopenic ASCC experience worse long-term outcomes. A retrospective review of patients with ASCC treated at an academic medical center from 2006 to 2017 was performed. Of 104 patients with ASCC, 64 underwent PET/computed tomography before chemoradiation and were included in the analysis. The skeletal muscle index was calculated as total L3 skeletal muscle divided by height squared. Sarcopenia thresholds were 52.4 cm2 /m2 for men and 38.5 cm2 /m2 for women. Cox regression analysis was performed to assess overall and progression-free survival. Twenty-five percent of the patients were sarcopenic (n = 16). Demographics were similar between groups. There was no difference in the clinical stage or comorbidities between groups. On multivariate analysis, factors associated with worse overall survival were male gender (hazard ratio [HR] 3.7, P = .022) and sarcopenia (HR 3.6, P = .019). Male gender was associated with worse progression-free survival (HR 2.6, P = .016). Sarcopenia is associated with worse overall survival in patients with anal cancer. Further studies are indicated to determine if survival can be improved with increased attention to nutritional status in sarcopenic patients.

Intensity-modulated radiotherapy (IMRT) in the treatment of squamous cell anal canal cancer: acute and early-late toxicity, outcome, and efficacy.

To retrospectively review our experience on 84 patients with squamous cell anal canal cancer (SCAC) within 12months after combined treatment with intensity-modulated RT (IMRT), in terms of acute and early-late toxicity, overall treatment time and interruptions, colostomy-free survival (CFS), and tumor response. Acute gastrointestinal (GI), genitourinary (GU), and cutaneous (CU) toxicities were assessed according to Common Toxicity Criteria for Adverse Events (CTCAE) version 4.03. Early-late toxicity was scored using the Radiation Therapy Oncology Group (RTOG) late radiation morbidity scoring system. Tumor response was evaluated with response evaluation criteria in solid tumors (RECIST) v1.1. Acute toxicity for 84 subjects (100%): severe (≥ G3) GI and skin toxicity was observed in 4 (5%) and 19 patients (23%), respectively. Early-late toxicity for 73 subjects (87%): severe (≥ G3) GI and vulvo-vaginal toxicity was observed in 2 (3%) and 2 (3%) patients, respectively. No acute or early-late severe GU toxicity was reported. A treatment interruption occurred in 65 patients (77%). CFS was 96% (95% CI 89-99) at 6months and 92% (95% CI 83-96) at 12months. At 6months complete response (CR), partial response (PR) and progressive disease (PD) was observed in 70 (83%), 3 (4%), and 7 patients (8%), respectively. At 12months, CR was observed in 60 patients (81%); eleven patients (15%) experienced PD. Our study showed an excellent clinical result and very low acute toxicity rates, confirming the IMRT as standard of care for curative treatment of anal cancer patients. The current trial was registered with the number IEO N87/11.

Improved survival in patients with FDG-PET/CT-based radiotherapy treatment planning for squamous cell anal cancer.

The aim of this retrospective analysis was to evaluate the impact of FDG-PET/CT-based target volume definition on locoregional control and survival, compared to conventional CT-based target volume definition and dose prescription. One hundred and twenty-two patients with squamous cell anal cancer were treated with curative radiotherapy (RT) alone (27%) or with RT with concurrent chemotherapy (73%) and analyzed. Forty-six percent had the early disease (stage I+II) and 54% were stage III. FDG-PET/CT-based staging was performed in 21% of the patients. The mean follow-up time was 60 months. Other risk factors affecting survival were investigated. According to initial staging in both groups (FDG-PET/CT and conventional CT) were 10% of stage IV disease, and they were excluded from radical radiotherapy and treated with palliative intent. Ninety-two percent of the patients achieved complete remission. Significant favorable factors in univariate analysis associated with disease-free survival (DFS) were PET/CT staging, T1/2 and N0 stage, and clinical stage I and II. Locoregional control (LRC) correlated with the T1/2 stage and initial performance status (PS) 0. There were no significant factors affecting overall survival (neither in univariate nor multivariate analysis). In multivariate analysis, the factor associated with better DFS was PET/CT staging and for LRC, PS 0 and concomitant chemoradiation. Acute toxicity was increased in the concurrent chemo-radiotherapy group. Two-, five- and ten-year overall survival rates were 83%, 69%, and 60%; disease-free survival rates were 76%, 73%, 73%; local control rates were 91%, 90%, and 90% and colostomy-free survival was 89%, 86%, and 81%, respectively. PET/CT staging allowed targeted dose escalation to the primary tumor and nodal metastases while decreasing dose to uninvolved regions, resulting in significantly improved DFS without compromising locoregional control.

Condyloma acuminata during pregnancy

Human papillomavirus (HPV) infection is the most common sexually transmitted viral infection. The sexually active individuals will acquire at least one type of HPV infection, frequently with more than one strain, and some people may be repeatedly infected. The patients with HPV infection during pregnancy represent a high-risk group. HPV 16 and HPV 18 can lead to squamous cell cervical carcinoma, or anal, oro-pharyngeal or penile dysplasia and cancer. HPV types 6 and 11 are responsible for over 90% of the genital or cutaneous condylomata acuminata. We aim to review the clinical implications for the diagnosis and the management of condylomas acuminata associated with pregnancy. The removal of condylomas during pregnancy, especially the larger ones, can be considered in order to minimise the risks during labor and childbirth; the resolution might be incomplete or poor until pregnancy is complete.

Neoadjuvant systemic therapy in melanoma: recommendations of the International Neoadjuvant Melanoma Consortium.

Advances in the treatment of metastatic melanoma have improved responses and survival. However, many patients continue to experience resistance or toxicity to treatment, highlighting a crucial need to identify biomarkers and understand mechanisms of response and toxicity. Neoadjuvant therapy for regional metastases might improve operability and clinical outcomes over upfront surgery and adjuvant therapy, and has become an established role for drug development and biomarker discovery in other cancers (including locally advanced breast cancer, head and neck squamous cell carcinomas, gastroesophageal cancer, and anal cancer). Patients with clinically detectable stage III melanoma are ideal candidates for neoadjuvant therapy, because they represent a high-risk patient population with poor outcomes when treated with upfront surgery alone. Neoadjuvant therapy is now an active area of research for melanoma with numerous completed and ongoing trials (since 2014) with disparate designs, endpoints, and analyses under investigation. We have, therefore, established the International Neoadjuvant Melanoma Consortium with experts in medical oncology, surgical oncology, pathology, radiation oncology, radiology, and translational research to develop recommendations for investigating neoadjuvant therapy in melanoma to align future trial designs and correlative analyses. Alignment and consistency of neoadjuvant trials will facilitate optimal data organisation for future regulatory review and strengthen translational research across the melanoma disease continuum.

Anal canal squamous cell cancer: surgıcal therapy, when?

Aim To describe a therapeutic approach, indications for abdominoperineal resection (APR), survival and oncological results for patients who received treatment in our surgical clinic for anal canal squamous cell cancer (SCC). Methods Patients were randomized into two groups according to the treatment method: Group 1- Chemoradiotherapy (CRT) without surgery, Group 2- CRT + APR. Results Eighteen patients with anal canal SCC were included in the study; 11 (61.1%) patients were in Group 1 and 7 (38.8%) in Group 2. Reasons for APR was as follows: three patients had insufficient CRT, two had recurrence after CRT, one had complete faecal incontinence and one patient had rectovaginal fistula. Overall five year survival (OS) and disease free survival (DFS) was 77.7% and 72.7%, respectively. Comparing two groups five year OS was 90.9% and 57.1%, whereas DFS was 81.8%, 57.1%, respectively (p=0.389 and 0.324, respectively). Conclusion Gold standard therapy for anal canal SCC is CRT. However, APR should be applied as an escape treatment for patients suffering from tumour progression, insufficient CRT and recurrence (30%).

A systematic review of outcomes after salvage abdominoperineal resection for persistent or recurrent anal squamous cell cancer.

Up to 30% of patients with squamous cell cancer of the anus (SCCA) will require a salvage abdominoperineal resection (APR) for either persistent or recurrent disease. The objective of this study was to assess cancer-related outcomes in patients with (i) persistent or (ii) recurrent SCCA. Embase and MEDLINE were searched. Publications were included if they assessed overall survival (OS), disease-free survival (DFS) and locoregional recurrence or metastatic disease after salvage APR for persistent or recurrent SCCA. A total of 28 retrospective case series (study size ranged from nine to 111) met our inclusion criteria. The median time to salvage APR was 2.6months [interquartile range (IQR) 2.6-5.0months, six studies] for persistent disease and 27.6months (IQR 15.0-32.7months, five studies) for recurrent disease. The median 5-year OS from the time of salvage APR was 45.0% (IQR 32.0%-52.3%, 10 studies) for persistent disease and 51.0% (IQR 36.0%-60.9%, 11 studies) for recurrent disease. The median 5-year DFS following salvage APR was 44.0% (IQR 29.5%-53.0%, 10 studies) for all patients. Following salvage APR, the median locoregional recurrence rate was 23.5% (IQR 15.8%- 46.9%, 19 studies) and 9.0% (IQR 6.4%-13.3%, 16 studies) of patients developed metastatic disease after salvage APR. Our review characterizes the best evidence for outcomes following salvage APR for patients with persistent or recurrent SCCA. The evidence is limited by the quality of included studies, as many were single centre case series.

Salvage abdominoperineal resection for squamous cell anal cancer: a 30-year single institution experience

Background: If chemoradiotherapy (CRT) for anal squamous cell carcinoma (SCC) fails, it results in persistent or recurrent anal SCC. Treatment with salvage abdominoperineal resection (APR) can potentially achieve cure. The aims of this study were to analyze oncological and surgical outcomes of our 30-year experience with salvage APR for anal SCC after failed CRT and identify prognostic factors for overall survival (OS).

Pelvic pouch cancers associated with inflammatory bowel disease

Patients with inflammatory bowel disease who undergo ileal pouch-anal anastomosis are at finite risk of developing neoplasia of various parts of the pouch. In this review article, we will describe different forms of pelvic pouch-related cancers, with a focus on diagnosis and management of small bowel adenocarcinomas of the pouch body, rectal neoplasia of the rectal cuff and anal transition zone, small intestinal lymphoma of the pouch, and anal dysplasia and squamous cell cancer of the anal canal.

Erythema multiforme occurring during concomitant chemoradiation for anal canal cancer: a case report

Background: Multimodality treatment is the mainstay of therapy for patients with locally advanced squamous cell anal cancer. This consistes of concurrent radiation and chemotherapy (including fluoropyrimidines and mitomycin). Several adverse skin reactions are associated with fluoropyrimidines. Case Presentation: Here, we describe the occurrence of an erythema multiforme in a patient treated with radiotherapy and concomitant mitomycin C and capecitabine for anal cancer. Conclusion: We underline the potential cutaneous drug-induced toxicity during pelvic radiotherapy with capecitabine.

Is There a Role for an 18F-fluorodeoxyglucose-derived Biological Boost in Squamous Cell Anal Cancer?

AimsTo investigate the potential role for a biological boost in anal cancer by assessing whether subvolumes of high 18F-fluorodeoxyglucose (FDG) avidity, identified at outset, are spatially consistent during a course of chemoradiotherapy (CRT). Materials and methodsFDG-positron emission tomography (FDG-PET) scans from 21 patients enrolled into the ART study (NCT02145416) were retrospectively analysed. In total, 29 volumes including both primary tumours and involved nodes >2 cm were identified. FDG-PET scans were carried out before treatment and on day 8 or 9 of CRT. FDG subvolumes were created using a percentage of maximum FDG avidity at thresholds of 34%, 40%, 50%, on the pre-treatment scans, and 70% and 80% on the subsequent scans. Both FDG-PET scans were deformably registered to the planning computed tomography scan. The overlap fraction and the vector distance were calculated to assess spatial consistency. FDG subvolumes for further investigation had an overlap fraction >0.7, as this has been defined in previous publications as a ‘good’ correlation. ResultsThe median overlap fractions between the diagnostic FDG-PET subvolumes 34%, 40% and 50% of maximum standardised uptake value (SUVmax) and subsequent FDG-PET subvolumes of 70% of SUVmax were 0.97, 0.92 and 0.81. The median overlap fraction between the diagnostic FDG-PET subvolumes 34%, 40% and 50% and subsequent FDG-PET subvolumes of 80% were 1.00, 1.00 and 0.92. The median (range) vector distance values between diagnostic FDG-PET subvolumes 34%, 40% and 50% and subsequent FDG-PET subvolumes of 80% were 0.74 mm (0.19–2.94) 0.74 mm (0.19–3.39) and 0.71 mm (0.2–3.29), respectively. Twenty of 29 volumes (69.0%) achieved a threshold > 0.7 between the FDG 50% subvolume on the diagnostic scan and the FDG 80% subvolume on the subsequent scan. ConclusionFDG-avid subvolumes identified at baseline were spatially consistent during a course of CRT treatment. The subvolume of 50% of SUVmax on the pre-treatment scan could be considered as a potential target for dose escalation.

Anal Intraepithelial Neoplasia and Squamous Cell Cancer of the Anus.

Anal intraepithelial neoplasia (AIN) is the premalignant condition of the anal squamous tissue. It is associated with the human papilloma virus and is considered the transition prior to the invasive anal squamous cell carcinoma. It is typically asymptomatic and can be either an incidental finding after anorectal surgery or identified when high-risk patient populations are screened. Once AIN is diagnosed, the optimal management remains controversial, partly because the natural history of the disease is unclear. Surgical management of the disease has essentially been replaced by more conservative treatment options and can range from expectant management to topical therapy to photodynamic therapy. The aim of this article is to review the varied treatment options and to briefly review prevention strategies.

Anal Intraepithelial Neoplasia and Squamous Cell Cancer of the Anus: Past, Present, and Future.

Anal Intraepithelial Neoplasia and Squamous Cell Cancer of the Anus: Past, Present, and Future.