The prevalence and incidence of colorectal cancer among patients with inflammatory bowel disease is less than 3% after colectomy and less than 1% after ileal pouch-anal anastomosis, according to the results of a systematic review and meta-analysis.
The researchers also identified residual rectum and history of colorectal cancer as risk factors for post-colectomy cancer risk.
“Colectomy, with or without reconstructive surgery, substantially reduces the risk to develop colorectal neoplasia,” Frank Hoentjen, MD, from the Inflammatory Bowel Disease Center at Radboud University Medical Centre in The Netherlands, and colleagues wrote. “However, neoplasia of the residual rectum or ileoanal pouch may still arise and is associated with a poor prognosis,” but more comprehensive data on this risk are needed to develop endoscopic surveillance guidelines for these patients.
The researchers therefore performed a systematic review and meta-analysis of studies published through May 2014 to ascertain the prevalence and incidence of colorectal dysplasia and cancer after colectomy in IBD patients with permanent ileostomy and rectal stump, ileorectal anastomosis (IRA) or ileal pouch-anal anastomosis (IPAA). They also aimed to identify risk factors associated with neoplasia in each group.
Researchers calculated CRC prevalence using 13 studies for rectal stump surgery patients (n = 1,011), 35 studies for IRA patients (n = 2,762) and 33 studies for IPAA patients (n = 8,403). CRC occurred in significantly greater proportions of rectal stump patients (2.1%; 95% CI, 1.3-3) and IRA patients (2.4%; 95% CI, 1.7-3) compared with IPAA patients (0.5%; 95% CI, 0.3-0.6), with a corresponding OR of 6.4 (95% CI, 4.3-9.5).
“The calculated prevalence and incidence for colorectal cancer following colectomy appeared relatively low, especially in the IPAA group,” Hoentjen told Healio Gastroenterology.
The most significant risk factor for CRC after colectomy was a history of CRC (IRA patients; OR = 12.8; 95% CI, 3.31-49.2; IPAA patients; OR = 15; 95% CI, 6.6-34.5). Additional risk factors for rectal of pouch neoplasia included IBD duration and a diagnosis of ulcerative colitis vs. Crohn’s disease.
Edward V. Loftus Jr
“These findings may aid in developing individualized post-surgical surveillance strategies,” Hoentjen said.
The researchers acknowledged that the limitations of their review include high risk of bias among the included studies, especially those of rectal stump patients, a majority of retrospective single-center studies that may introduce selection and recall bias, neoplasia development as a secondary outcome in many studies, significant heterogeneity across studies, and highly variable duration of follow-up and publication date.
“Despite these limitations, these observations inform us well on the risk of cancer after colectomy,” Siddharth Singh, MD, MS, from University of California San Diego, and Edward V. Loftus Jr, MD, from the Mayo Clinic, wrote in a related editorial. “First of all, the overall prevalence of cancer developing in the pouch after IPAA is very low. ... Second, the estimated prevalence of cancer after colectomy is 6.4 times higher after procedures in which the rectum was left intact.”
Singh and Loftus concluded that these findings underscore the need for continued vigilance in surveilling this patient population for dysplasia and cancer, especially those with a history of CRC or dysplasia and long IBD duration. – by Adam Leitenberger
Disclosures: The researchers and editorial authors report no relevant financial disclosures.
Editor's note: This article was updated on June 20 with additional comments from a study author.