Patients with Crohn's disease are at increased risk of colorectal cancer.
However, little is known about the impact of Crohn's disease on colorectal cancer prognosis.
Based on nationwide population-based registries, Dr Mette Larsen and colleagues from Denmark compared survival among colorectal cancer patients with and without Crohn's disease.
The team used the Danish Cancer Registry and the Danish Hospital Discharge Registry to identify all patients for the study conducted between 1977 and 1999.
The research team ascertained the stage distribution at the time of colorectal cancer diagnosis.
The researchers also evaluated the 1- and 5-yr survival both for patients with and without Crohn-associated colorectal cancer.
|The hazard ratio for colorectal cancer with Crohn's was 1.6 after 5 years
|American Journal of Gastroenterology|
Cox regression was used to compute hazard ratios, adjusting for gender, age, calendar year, and stage.
The research team identified 100 colorectal cancer patients with Crohn's disease, and 71,438 colorectal cancer patients without Crohn's disease.
At the time of diagnosis, patients with Crohn's disease were younger, but stage distributions were similar in the 2 groups.
The researchers observed that the overall hazard ratios for colorectal cancer patients without Crohn's disease was 1.8 after 1 year of follow-up.
The hazard ratio for colorectal cancer with Crohn's disease was 1.6 after 5 years of follow-up.
The team showed that the effect of Crohn's disease on colorectal cancer survival was more pronounced in the youngest patients, and in men.
In addition, the researchers found that the effect of Crohn's disease on colorectal cancer survival was more pronounced with tumors that had regional spread.
Dr Larsen's team concludes, “We found that Crohn's disease worsens the prognosis of colorectal cancer, particularly with regional spread.”