1. CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2012;10:1179 –1180
LETTERS TO THE EDITOR
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Challenges in Calculating the Risk for 1.01–3.0) with a median follow-up of 10 years. This is remark-
Colorectal Cancer in Patients With able, because the similar range of SIRs across different geo-
graphic areas—including now Eastern Europe—may support
Ulcerative Colitis that chronic inflammation contributes in a similar, additive
Dear Editor: manner to the initiation of carcinogenesis in the colon, irre-
We read with interest the report by Jess et al1 on the meta- spective of the pre-existing baseline risk or geographic differ-
analysis of the risk of colorectal cancer (CRC) in patients with ences. Second, previous studies have identified multiple risk
ulcerative colitis (UC) in population-based cohort studies. The factors for UC-associated CRC. In the study by Jess et al,1 males
major finding of the study was that the risk of UC in popula- (SIR, 2.6; 95% CI, 2.2–3.0 vs females: SIR, 1.9; 95% CI, 1.5–2.3)
tion-based cohorts was increased. However, it was significantly and patients with extensive colitis (SIR, 4.8; 95% CI, 3.9 –5.9)
lower than previously reported in the landmark meta-analysis had a greater risk, similar to recent Swedish data. In the pop-
by Eaden et al.2 In the present meta-analysis, an average of 1.6% ulation-based Hungarian cohort, the SIR was also increased in
of patients with UC were diagnosed with CRC during the first patients with extensive colitis (SIR, 4.1; 95% CI, 2.0 – 8.1), and a
14 years of follow-up. The pooled standardized incidence ratio tendency of increased SIRs was seen in females and males.
(SIR) was 2.4 (95% confidence interval [CI], 2.1–2.7). Neverthe- Other potential risk factors include age at onset, disease dura-
less, it is important to highlight potential limitations of the tion, primary sclerosing cholangitis, and medication history
study before accepting the above general conclusion. One of the (including exposure to 5-aminosalicylates/azathioprine).
most important possible confounders is the high percentage of In summary, communication of cancer risk in ulcerative
proctitis (45%– 60%) in about half of the cohorts. In addition, colitis and patient management strategies should be tailored to
the rate of colectomy was exceedingly high (16%–31%), espe- specific patients based on age, sex, disease extent, disease dura-
cially compared with the relatively short median follow-up tion, geographic area, and presence of factors including age at
period. Geographic imbalance is also apparent, with 5 out of 8 onset, disease duration, and primary sclerosing cholangitis.
studies coming from the Nordic countries. Furthermore, al- PETER L. LAKATOS, MD, PhD
though authors interpreted the positive association between First Department of Medicine
cohort size and CRC risk as a confirmatory factor against Semmelweis University
publication bias, an alternative explanation is that the patient Budapest, Hungary
population in the study by Söderlund et al was significantly
different from other cohorts included in this meta-analysis with LASZLO LAKATOS, MD, PhD
only 27% of patients having proctitis at diagnosis.3 Interest- Department of Medicine
ingly, other population-based cohorts from Scandinavia also Csolnoky F. Province Hospital
reported a lower percentage of proctitis at diagnosis, and com- Veszprem, Hungary
parable data (25.3%) were reported by our group from Eastern
1. Jess T, et al. Clin Hepatol Gastroenterol 2012;10:639 – 645.
Europe.4 In addition, colectomy rates have shown large geo- 2. Eaden JA, et al. Gut 2001;48:526 –535.
graphic variation with significantly lower rates reported from 3. Söderlund S, et al. Gastroenterology 2009;136:1561–1567.
the Mediterranean and Eastern Europe in previous studies. 4. Lakatos L, et al. Inflamm Bowel Dis 2006;12:205–211.
Consequently, in contrast to the meta-analysis by Eaden et al,2
the present meta-analysis potentially underestimated the actual
CRC risk in UC. Generalizability of results is therefore ques-
tionable, and geographic restrictions may also apply. Conflicts of interest
Nevertheless, communicating only the overall SIR to the The authors disclose no conflicts.
patients can be misleading because of at least 2 reasons. First, http://dx.doi.org/10.1016/j.cgh.2012.04.021
there is substantial variation in the incidence of sporadic CRC
worldwide. The incidence of sporadic CRC in the Western world Reply. We thank Drs Lakatos and Lakatos for commenting on
is approximately 30 to 40 per 100,000. In contrast, correspond- our meta-analysis on risk of colorectal cancer (CRC) in patients
ing numbers (eg, in Hungary) are 81 per 100,000 in males and with ulcerative colitis (UC).1 We agree that the results of our
50 per 100,000 in females. This is one of the highest sporadic meta-analysis are different from those of the meta-analysis by
CRC incidences reported worldwide. Therefore, a similar SIR Eaden and colleagues from 2001.2 We believe that this differ-
may correspond to considerable different absolute CRC risk in ence is explained by the unselected nature of the cohort studies
different geographic areas (eg, the cumulative risk of developing included in the present meta-analysis. Reassuringly for patients,
CRC after a disease duration of 15 and 20 years was 2.6% and we observed a more modestly increased risk of CRC in UC than
5.4% in the Hungarian cohort).4 After the original publication, in the former meta-analysis, which included selected patient
SIR rates were calculated for the Hungarian UC patients. In series.2 Due to the strict inclusion criteria in the present meta-
concordance with the results of the above meta-analysis, the analysis, we believe that our results are inherently more gener-
overall SIR in this Eastern European cohort was 1.74 (95% CI, alizable to the broad spectrum of UC patients and especially to