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Liver‐transplant recipients (LTRs) are known to carry an increased risk of cancer, including tumours of the skin and lymphoproliferative disorders.1 Whether the risk of colorectal cancer (CRC) is increased after orthotopic liver transplantation (OLT) is controversial.2 There is also no consensus whether screening for colorectal neoplasia in asymptomatic LTRs is warranted, except for those with primary sclerosing cholangitis (PSC) with associated ulcerative colitis (UC).2 In a previous study, we found an increased risk of CRC in patients after OLT compared with the general population.3 In this report, we examined the prevalence of colorectal adenomas and carcinomas in asymptomatic LTRs.
Between 1979 and 2001, 381 adult patients underwent OLT at the University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. For this retrospective study, all patients were included in which a colonoscopy had been performed for screening purposes, at least 5 years after OLT. Patients with symptoms suggestive of colorectal neoplasia and patients with previous colorectal neoplasia were excluded. Only complete colonoscopy reports including caecal inspection were included. Data on the presence, location and number of colorectal neoplastic lesions were collected. Patients with more than one lesion were categorised according to the most advanced lesion. All pathological specimens were reviewed by the study pathologist for assessment of the degree of dysplasia and the presence of villous architecture according to the World Health Organization criteria.4 Advanced neoplasia was defined as an adenoma of at least 1 cm in size, and/or (tubulo) villous architecture, and/or high‐grade dysplasia, or cancer, in accordance with the literature.
In all, 92 asymptomatic patients, including 20 with PSC, had undergone colonoscopy at a median (range) age of 53.5 (35.8–71.2) years, after a median (range) interval of 11.1 (5.0–23.2) years after OLT. One or more adenomas were found in 20 of 92 (21.7%) patients (9 men, 11 women). Of these 20 patients, 4 had PSC, including 1 with concomitant UC. In 9 of 20 patients, one or more adenomas were located in the proximal colon. Advanced adenomas were found in 8 of 92 (8.7%) patients. Cancer was found in none of the patients.
These prevalence data in patients with OLT were compared with six asymptomatic cohorts from the literature (table 11).). Although the prevalence of all neoplasia was comparable with other cohorts, advanced neoplasia was more often found in our population than in most studies. In addition, the relative proportion of advanced neoplasia, expressed as a ratio of all neoplasia, was 0.40 in our study, which is higher than in any other report. As the prevalence of colorectal neoplasia increases with age, data from our population were compared with data from the literature stratified in three groups (<50, 50–59 and >60 years). For patients aged <50 years and 50–59 years, the prevalence of advanced neoplasia was higher in our study population than in any other study (table 11).). Our data are probably best compared with the only other available Dutch study that was performed in a relatively young asymptomatic population.5 In patients aged <50 years, the relative risk in the population which underwent OLT was 3.6 (p<0.05) for overall neoplasia and 8.9 (p<0.01) for advanced neoplasia. Taken together, our data suggest that LTRs have a higher risk of colorectal neoplasia, particularly advanced neoplasia, compared with average‐risk populations. The absence of a gender‐ and age‐matched control group limits the strength of this retrospective study. We suggest designing larger and prospective studies including adequate control groups to better assess the risk of colorectal neoplasia in LTRs.
Currently, CRC screening is recommended in many countries worldwide for all patients aged 50 years. It was recently recommended that for the asymptomatic liver transplant population, CRC screening should be offered to those aged >50 years and those with PSC associated UC.2 The results from our preliminary study suggest that CRC screening could be considered in all adult LTRs.
Competing interests: None.