Background: Chronic inflammatory bowel disease is associated with an increased risk of colorectal neoplasia. Despite the use of colonoscopic screening, patients continue to present with colorectal malignancies. The purpose of this study was to review the clinical and pathologic features of a cohort of patients undergoing resection for colitis-associated neoplasia (CAN) at our institution.
Methods: Patients who had resections between 1989 and 2000 were identified using prospectively obtained information on our IBD database, as well as a review of the hospital's pathology department database searching for the combined diagnoses of IBD and colon or rectal cancer. Clinical and pathologic data were obtained from information contained in the database, and by review of the patients' hospital and office charts.
Results: Forty-two patients with 54 colitis-associated neoplasms treated at our institution were identified. There were 37 cancers, 12 dysplasia-associated lesions or masses(DALM), and 5 high grade dysplasias. Of the cancers, 12 were T1 lesions, 6 were T2, 14 were T3, and 3 were T4. Seven patients had stage 3 disease, while 5 had stage 4. Thirty-nine percent of the neoplasms were right sided, 28% were left sided, and 33% were rectal. Ten cancers (27%) had mucinous differentiation. The mean age of onset of IBD was 32.5 (+/-18.1)years, and the mean time from diagnosis of IBD to diagnosis of neoplasia was 16.9 (+/-10.6)years. However, considering the recommendation of beginning screening only after 8 years of disease, 10 (24%) of our patients presented with neoplasia within 8 years of their diagnosis of IBD. Additionally, 14 patients (33%) had negative endoscopy and the neoplasia was found incidentally in their resected specimen. Eight (19%) patients had a family history of IBD, while 11 (26%)had a family history of colorectal cancer.
Conclusions: Colitis-associated neoplasia continues to present a challenging problem to the practising clinician. These patients often present with neoplasia at an earlier age, and often seem to have an aggressive course, with relatively frequent unfavourable histology. Despite surveillance, one third of the patients in this series had their neoplasm missed, and only diagnosed on pathologic exmination of their resected colon. A family history of IBD and/or colorectal cancer was frequently present, suggesting possible genetic factors leading to neoplastic development. Further research in this group of patients is warranted.