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P658. Colorectal cancer in primary sclerosing cholangitis: the importance of surveillance

K. Boonstra1, R. Weersma2, K.J. van Erpecum3, E. Rauws1, M. Spanier4, A. Poen5, K. van Nieuwkerk6, J. Drenth7, B. Witteman8, H. Tuynman9, A. Naber10, P. Kingma11, H. van Buuren12, B. van Hoek13, F. Vleggaar3, U. Beuers1, C. Ponsioen1, 1Academic Medical Center Amsterdam, Gastroenterology and Hepatology, Amsterdam, Netherlands, 2University Medical Center Groningen, Gastroenterology and Hepatology, Groningen, Netherlands, 3University Medical Center Utrecht, Gastroenterology and Hepatology, Utrecht, Netherlands, 4Rijnstate Hospital, Gastroenterology and Hepatology, Arnhem, Netherlands, 5Isala Clinics, Gastroenterology and Hepatology, Zwolle, Netherlands, 6VU Medical Center, Gastroenterology and Hepatology, Amsterdam, Netherlands, 7Radboud University Nijmegen Medical Center, Gastroenterology and Hepatology, Nijmegen, Netherlands, 8Gelderse Vallei Hospital, Gastroenterology and Hepatology, Ede, Netherlands, 9Medical Center Alkmaar, Gastroenterology and Hepatology, Alkmaar, Netherlands, 10Tergooiziekenhuizen, Gastroenterology and Hepatology, Hilversum, Netherlands, 11Tergooiziekenhuizen, Gastroenterology and Hepatology, Blaricum, Netherlands, 12Erasmus University Medical Center, Gastroenterology and Hepatology, Rotterdam, Netherlands, 13Leiden University Medical Center, Gastroenterology and Hepatology, Leiden, Netherlands

Background

PSC is an additional and independent risk factor for the development of colorectal cancer in ulcerative colitis patients, although low absolute numbers often hamper standardized incidence ratio analysis, emphasizing the need for large population-based cohorts. We aimed to study the CRC risk in PSC and IBD patients in two large population-based PSC and IBD cohorts and evaluate the effect of regular surveillance colonoscopies.

Methods

All PSC patients were identified in a large geographically defined area of The Netherlands, comprising 50% of the Dutch population. Four hospital databases were searched in 44 hospitals. In addition, all PSC patients in the 3 Dutch liver transplant centers and all inflammatory bowel disease (IBD) patients in the adherence area of a large district hospital were identified. All medical records were reviewed on site for verification of diagnosis and data collection.

Results

The case-finding and case-ascertainment strategy resulted in a population-based cohort of 590 PSC patients. The second PSC cohort, accrued from the three Dutch transplantation centers outside the study region yielded 450 cases. The IBD control cohort comprised 722 cases. The median follow up from diagnosis until death or end of study was 92 months (0–470). In the population-based PSC cohort, 19 PSC-IBD patients developed CRC (18 UC, 1 CD) after a median time between IBD diagnosis and CRC of 15 years (range 0–35). Seven (1%) IBD control patients developed CRC (SIR 1.2; 95% CI 0.3–3.0) after a median time span of 4 years [range 0–19] after diagnosis (4 UC, 2 CD, 1 IBD-U). There was a 10-fold increased risk for developing CRC in PSC-UC patients compared to UC controls (ratio of SIRs 9.8; 95% 1.9–96.6). For PSC-IBD patients, the cumulative risk of CRC after 10, 20, 30, and 40 years since IBD diagnosis was 1%, 6%, 13%, and 17%, respectively. Surveillance colonoscopies had been performed prior to CRC diagnosis in 10 (53%) PSC-IBD patients. When combining PSC-CRC patients from the population-based and transplantation centers cohorts 50% (9/18) of the non-surveilled patients and 16% (3/19) of the patients who received regular surveillance colonoscopies died of CRC (P = 0.038).

Conclusion

Risk of CRC in a population-based IBD cohort was equal to the general population. CRC risk was 10-fold increased in PSC-UC patients as compared to UC controls. Regular surveillance colonoscopies prior to CRC diagnosis were associated with significantly less CRC-related mortality in PSC-CRC patients.