Population-based data from the Swedish Colon Cancer Registry

Background Evaluating the external validity of clinical trials requires knowledge not only of the study population but also of a relevant reference population. The main aim of this study was to present data from a large, contemporary, population-based cohort of patients with colonic cancer. Methods Data on patients diagnosed between 2007 and 2011 were extracted from the Swedish Colon Cancer Registry. The data, registered prospectively in a national population of almost 10 million, included over 99 per cent of all diagnosed adenocarcinomas of the colon. Results This analysis included 18889 patients with 19526 tumours (3 center dot 0 per cent had synchronous tumours). The sex distribution was fairly equal, and the median age was 74 center dot 1 (interquartile range 65-81) years. The overall and relative (cancer-specific) survival rates after 3 years were 62 center dot 7 and 71 center dot 4 per cent respectively. Some 88 center dot 0 per cent of the patients were operated on, and 83 center dot 8 per cent had tumours resected. Median blood loss during bowel resection was 200 (mean 311) ml, and the median operating time was 160min; 5 center dot 6 per cent of the procedures were laparoscopic. Preoperative chemotherapy was administered to 2 center dot 1 per cent of patients; postoperative chemotherapy was planned in 90 center dot 1 per cent of fit patients aged less than 75 years with stage III disease. In patients operated on in an emergency setting (21 center dot 5 per cent), the preoperative evaluation was less extensive, the proportion of R0 resections was lower, and the outcomes were poorer, in both the short and long term. Conclusion These population-based data represent good-quality reference points.