English summary
Backgr ound
Colorectal cancer is one of the most common cancers with an estimated incidence of 1.7 million worldwide. Patients presenting with acute symptoms like tumour obstruction or bowl perforation, are operated acutely with a high risk of postoperative mortality. Around 10% of all colorectal cancer surgeries are performed as an acute procedure and the 30-day mortality risk varies from 6% to 22%.
Aim
The aim of this thesis was to investigate if the postoperative mortality after acute colorectal cancer surgery has improved in Denmark within the last ten years and to identify risk factors for early death. We
furthermore aimed to investigate whether low socioeconomic position was associated with the risk of having colorectal cancer surgery as an acute procedure and subsequently if low socioeconomic position was associated with decreased 1-year survival. We aimed to validate if the Association of Coloproctology of Great Britain and Ireland (ACPGBI) model could predict 30-day mortality after colorectal cancer surgery in Denmark. The final aim of this thesis was to develop a model to preoperatively predict the risk of postoperative 90-day mortality in acutely operated patients with colorectal cancer.
Methods a nd resul t
All four studies of this PhD thesis were register-based historical cohort studies. Data were mainly collected from the Danish Colorectal Cancer Group database and the Danish National Patient Registry. Patients were included from 2005 to 2015. In the thesis, we found that the 90-day mortality has improved in Denmark within the last 10 years. Age, comorbidity, metastatic diseases and diverging stoma were associated with increased risk of postoperative mortality. Socioeconomic indicators associated with increased 90-day postoperative mortality were low educational level, low income and living alone. The same socioeconomic indicators were associated with the likelihood of acute versus elective surgery for colorectal cancer. The ACPGBI prediction model was not appropriate to identify patients at high mortality risk. In this thesis, the first model to preoperatively predict mortality in acutely operated patients with colorectal cancer is presented. In the external validation the model had a good accuracy, an acceptable discrimination and a calibration with underestimation of mortality.
Conclusion
The overall finding of this PhD thesis was that 90 day-mortality has improved in Denmark within the last 10 years but has remained as high as 24% in 2015. This thesis was the first to present the association between low socioeconomic position and decreased 1-year survival in acute colorectal cancer surgery. It was confirmed that also in Denmark, individuals with low socioeconomic position are more likely to have acute colorectal cancer surgery compared with elective. Finally, a model to predict 90-day mortality after acute colorectal cancer surgery was presented in this PhD thesis.
