Introduction Collagenous colitis (CC) is a syndrome of chronic, watery, non-bloody diarrhoea.¹ Its worldwide incidence is increasing; emerging evidence suggests a possible association between CC and malignancy.² However, studies thus far have been inconclusive and data on the incidence of metachronous extra-colonic malignancy (MEcM) in CC is scarce.³ This study aimed to determine the occurrence of MEcM in patients with CC.

Methods Retrospective study; data on MEcM in patients previously diagnosed with CC was collected within NHS Lothian (Scotland) over a 14 year period (Jan 2000 – Nov 2013). Person-years at risk were calculated according to age-specific categories. The standard error (Se) was calculated using the Poisson approximation. Relative risk (RR) and confidence interval (CI) of the age-standardised rate (ASR) were compared to publicly available population data for Lothian, Scotland.⁴ Results are reported as average ± standard deviation or RR with confidence interval (CI). P values <0.05 were considered statistically significant.

Results In the aforementioned period, 394 patients were diagnosed with CC and included for analysis. Thirty-three (21 F/12 M) developed MEcM, Table 1. The average age of the group with MEcM was 71.6 ±7.4 years compared to 65.9 ±13.6 years for the remainder of the patients (P < 0.05). The average duration of follow-up from CC diagnosis to MEcM was 2 ±2.23 years and for the group as a whole was 4 ±3.45 years. The RR for lung cancer (4.63, 1.30;16.49) and total cancers (2.34, 1.38;3.95) in patients with CC was higher compared to population data from Lothian (P < 0.05 for both).

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Abstract PTU-053 Table 1

Conclusion The RR of MEcM, including lung cancer, is higher in patients with CC.The increased RR for lung cancer may be explained by the association between CC and smoking.⁵

Further collective data will be useful to clarify other associations.

References 1 Münch A, et al. Microscopic colitis: current status, present and future challenges: statements of the European Microscopic Colitis Group. J Crohn’s Colitis 2012;6:932–945.

2 Freeman HJ. Complications of collagenous colitis. World J gastroenterol 2008;14:1643.

3 Chan JL, et al. Cancer risk in collagenous colitis. Inflamm Bowel Dis 1999;5:40–43.

4 http://www.ncin.org.uk/cancer_information_tools/eatlas/guide

5 Vigren L, et al. Is smoking a risk factor for collagenous colitis? Scand J Gastroenterol 2011;46:1334–1339.

Disclosure of Interest None Declared