Su1287 Anal Neoplasia in Inflammatory Bowel Disease Is Associated With HPV and Perianal Disease

Abstract

Background: Patients with inflammatory bowel disease (IBD) may develop anal squamous cell carcinoma. Little is known about predisposing factors. Design: We retrospectively reviewed the records of IBD patients diagnosed with anal neoplastic lesions presenting at our Center between March 1st 1994 and September 9th 2014. Histological specimens were reviewed to classify anal neoplastic lesions. Presence of HPV was assessed using immunohistochemical staining in combination with global and type-specific molecular PCR for HPV16 and 18. Lesions with p16 block-positive staining (p16+) and negative PCR for HPV underwent additional immunostaining for p53. Results: We identified 17 IBD patients with anal neoplastic lesions (8M/9F, 9 ulcerative colitis/7 Crohn's disease/1 indeterminate colitis). Invasive squamous cell carcinomas (SCCs), high grade anal intraepithelial neoplasms (ASIN-H) and low grade anal intraepithelial neoplasm (ASIN-L) were identified respectively in 6, 8 and 3 patients. In the SCC group, 5/6 patients had Crohn's disease with perianal involvement compared to 2/8 and 0/3 in the ASIN-H and ASIN-L group, respectively. Information regarding medical therapy at the time of anal cancer diagnosis was available in 10 patients, of which 5, 2 and 2 were on thiopurine, steroids and biological therapy, respectively. In patients with SCC, 3/6 and 1/6 were HPV 16+ and 18+ respectively. The patient who was HPV18+ had more than a 10 year history of UC and underwent proctocolectomy with ileo-anal pouch anastomosis 11 years before development of anal cancer. Eight out of 8 patients with ASIN-H lesions were HPV16 but not 18 positive. One out of 3 patients with ASIN-L was HPV16+. Conclusion: In our experience, anal neoplasia in IBD is associated with HPV infection and perianal Crohn's disease. Prospective studies are needed to confirm these results.