Tumours of the anal canal

Monitoring Patients With Inflammatory Bowel Disease at High Risk of Anal Cancer

Anal cancer is a rare but deadly disease that disproportionately affects patients with inflammatory bowel disease (IBD). Rates of adenocarcinoma and human papillomavirus-related squamous cell carcinoma have been consistently demonstrated to be higher in patients with ulcerative colitis and Crohn's disease. Despite this increased risk, uniform screening, diagnosis, and treatment algorithms are lacking. This review describes the most recent literature surrounding anal cancer in the IBD population as well as the unique challenges inherent in diagnosing and treating this population. We conclude by proposing a new screening motif based off literature review and multidisciplinary clinical experience that aims to increase early detection of anal cancers in the IBD population.

Gastric squamous-columnar junction contains a large pool of cancer-prone immature osteopontin responsive Lgr5-CD44+ cells

Areas of a junction between two types of epithelia are known to be cancer-prone in many organ systems. However, mechanisms for preferential malignant transformation at the junction areas remain insufficiently elucidated. Here we report that inactivation of tumor suppressor genes Trp53 and Rb1 in the gastric squamous-columnar junction (SCJ) epithelium results in preferential formation of metastatic poorly differentiated neoplasms, which are similar to human gastroesophageal carcinoma. Unlike transformation-resistant antral cells, SCJ cells contain a highly proliferative pool of immature Lgr5⁻CD44⁺ cells, which are prone to transformation in organoid assays, comprise early dysplastic lesions, and constitute up to 30% of all neoplastic cells. CD44 ligand osteopontin (OPN) is preferentially expressed in and promotes organoid formation ability and transformation of the SCJ glandular epithelium. OPN and CD44 overexpression correlate with the worst prognosis of human gastroesophageal carcinoma. Thus, detection and selective targeting of the active OPN-CD44 pathway may have direct clinical relevance.

Cancers arising from the gastric squamous-columnar junction have high incidence and are characterized by a poor prognosis. Here, the authors use genetic mouse models to show that loss of p53 and Rb1 expression results in preferential tumour development at the gastric squamous-columnar junction that contains a large pool of osteopontin responsive Lgr5-CD44+ cells.

A systematic review of anal squamous cell carcinoma in inflammatory bowel disease

AIM

The aim of this systematic review was to determine the incidence, aetiology and clinical characteristics of anal squamous cell carcinomas (SCC) presenting in patients with inflammatory bowel disease.

METHOD

A systematic review of the literature was undertaken using Medline, Embase, Cochrane and Web of Science.

RESULTS

A total of 33 cases of anal SCC were described, 7 in ulcerative colitis (UC) and 26 in Crohn's disease (CD). The annual incidence of anal SCCs was 0.9/100,000 and 2.0/100,000 in patients with UC and CD respectively. The gender ratio in CD was 3M:17F with a median age of 42 years, the main presenting symptom was anal pain and 85% of CD cases had peri-anal disease. No studies described anal intra-epithelial neoplasia. The human papilloma virus was found to be positive in 2 out of 5 (40%) cases. The majority of patients (73%) with CD received radical surgery as their first line treatment. The cumulative overall and disease free survival in CD was 37 per cent at five years.

CONCLUSION

The findings of this review when contrasted with the data from cancer registries suggests that there is a higher incidence of anal SCC, an earlier age of presentation and poorer outcomes in patients with Crohn's disease compared to the general population implying a more aggressive neoplastic process. This review supports the hypothesis that peri-anal disease plays a contributing role in anal SCCs and as such targeted surveillance in patients with longstanding peri-anal disease should be considered.

Recurrence of anal adenocarcinoma after local excision and adjuvant chemoradiation therapy: report of a case and review of the literature

INTRODUCTION

Tumors arising from the anal canal are rare, comprising 1.5% of all gastrointestinal tumors in the USA. The vast majority of these anal cancers are epidermoid (cloacogenic/basaloid and squamous cell carcinomas), while adenocarcinomas reportedly occur 5% to 19% of the time. Because of its rarity, reports about anal adenocarcinoma are limited to small retrospective studies and case reports. Moreover, no series has directly compared outcomes between patients undergoing the various available treatment options, making it difficult to determine the optimal treatment for this aggressive cancer. Current management of this cancer remains controversial, with some authors believing abdominoperineal resection with permanent colostomy should be considered the standard treatment. Others propose that combined chemoradiation be adopted as a possible treatment in certain patients.

CASE PRESENTATION

We describe a case of recurrent anal adenocarcinoma after conservative management with local excision and adjuvant chemoradiation therapy.