Risk of colorectal carcinoma in post-liver transplant patients: a systematic review and meta-analysis.

Liver transplant patients (LTx) have an increased risk for developing de novo malignancies, but for colorectal cancer (CRC) this risk is less clear. We aimed to determine whether the CRC risk post-LTx was increased. A systematic search was performed in MEDLINE and Cochrane databases to identify studies published between 1986 and 2008 reporting on the risk of CRC post-LTx. The outcomes were (1) CRC incidence rate (IR per 100,000 person-years (PY)) compared to a weighted age-matched control population using SEER and (2) relative risk (RR) for CRC compared to the general population. If no RR data were available, the RR was estimated using SEER. Twenty-nine studies were included. The overall post-LTx IR was 119 (95% CI 88-161) per 100,000 PY. The overall RR was 2.6 (95% CI 1.7-4.1). The non-primary sclerosing cholangitis (PSC) IR was 129 per 100,000 PY (95% CI 81-207). Compared to SEER (71 per 100,000 PY), the non-PSC RR was 1.8 (95% CI 1.1-2.9). In conclusion, the overall transplants and the subgroup non-PSC transplants have an increased CRC risk compared to the general population. However, in contrast to PSC, non-PSC transplants do not need an intensified screening strategy compared to the general population until a prospective study further defines recommendations.