A meta-analysis of the clinicopathological characteristics and survival outcomes of inflammatory bowel disease associated colorectal cancer versus sporadic colorectal cancer
Ian Reynolds, Aobhlinn O’Toole, Joseph Deasy, Deborah A. McNamara, John P. Burke
Departments of Colorectal Surgery and Gastroenterology, Beaumont Hospital, Dublin, Ireland.
Patients with inflammatory bowel disease (IBD) have an established increased risk of developing colorectal carcinoma (CRC). There is no consensus, however, on the clinicopathological characteristics and survival outcomes of IBD associated CRC when compared to sporadic CRC.
The aim of this study was to use meta-analytical techniques to compare IBD associated CRC to sporadic CRC.
A systematic search of PubMed and Embase was performed for all studies published comparing outcomes of patients treated for IBD associated and sporadic CRC by using the following in the search algorithm: (crohn's OR colitis) AND (cancer) AND (colorectal). The Cochrane Central Register of Controlled Trials was also searched for articles. Comparative studies of IBD associated and sporadic CRC containing data on tumor differentiation, tumor T, N and M stage at diagnosis, sex distribution, synchronous tumors and overall survival were eligible for inclusion. Studies describing outcomes in IBD associated CRC only with no comparative data were excluded. Studies describing patients with small bowel tumors were not included. There were no language restrictions. Only studies that reported survival at 5 years following diagnosis were included in the survival analysis. All pooled outcome measures were determined using a random-effects model. The quality of included studies was assessed by using the Newcastle-Ottawa Scale.
Data were retrieved from 20 studies describing 571,278 patients. IBD associated CRC had an increased rate of synchronous tumors (OR: 4.403, 95% CI: 2.320-8.359, p<0.001), poor differentiation (OR: 1.875, 95% CI: 1.425-2.466, p<0.001) and a reduced rate of rectal cancer (OR: 0.827, 95% CI: 0.735-0.930, p: 0.002). IBD associated CRC however did not affect the frequency of T3/T4 tumors (OR: 0.931, 95% CI: 0.782-1.108, p: 0.421), lymph node positivity (OR: 1.061, 95% CI: 0.929-1.213, p: 0.381), metastasis at presentation (OR: 0.970, 95% CI: 0.776-1.211, p: 0.786), sex distribution (OR: 0.978, 95% CI: 0.890-1.074, p: 0.640) or 5 year overall survival (OR: 1.105, 95% CI: 0.414-2.949, p: 0.842).
In this large analysis of available data, IBD associated CRC was characterized by more synchronous and poorly differentiated tumors compared with sporadic cancers, but no discernable difference in survival could be identified.