Differences in pre-operative treatment for rectal cancer between Norway, Sweden, Denmark, Belgium and the Netherlands.

Several studies have shown remarkable differences in colorectal cancer survival across Europe. Most of these studies lacked information about stage and treatment. In this study we compared short-term survival as well as differences in tumour stage and treatment strategies between five European countries: Norway, Sweden, Denmark, Belgium, and the Netherlands. For this retrospective cohort study all patients aged 18 years or older and operated on adenocarcinoma of the rectum without distant metastases and diagnosed in 2008 and 2009 were selected in national audit registries from Norway, Sweden, Denmark, Belgium, and the Netherlands. Differences in pre-operative treatment between the countries were compared using univariable and multivariable logistic regression. One year relative survival and one year relative excess risk of death (RER) were compared between the five countries. Large variation in the use of preoperative radiotherapy and chemoradiation was found between the countries. Even though, there was little variation in relative survival between the countries, except Sweden, which had a significant better one year RER of death among the elderly patients after adjustment. The differences in survival are expected to be caused by differences in peri-operative care, selection of patients, and especially management of elderly patients. The effects of preoperative treatment are expected to be seen on long term follow-up.