Emergent colon cancer and postoperative complications - risks and management

Background:
Colorectal cancer in the third most diagnosed cancer in Sweden and the second most common cause of cancer-related death in Sweden and worldwide. 10-30% of the cases present as emergencies, of which 80% are caused by large bowel obstruction (LBO). Most of these patients undergo emergency resection which is associated with high rates of morbidity and mortality. To overcome the risk with emergency resection (ER) the patients can be managed with a staged preocedure or bridge to surgery (BTS) which encompasses decompression of the bowel, either with stent or deviating stoma, followed by planned resection surgery. Data in these studies comes from the Swedish Colorectal Cancer Registry (SCRCR) which is proofed to have high validity.
Aims:
To evaluate the impact of postoperative complications after curative resection of colon cancer on long-term survival.
To compare short- and long-terms outcome after management of acute malignant large bowel obstruction with Bridge to Surgery or emergency resection.
To evaluate short- and long-term outcomes following emergent colon cancer surgery depending on sub-specialization of the operating team.
To evaluate the reliability of data from the Swedish Colorectal Cancer Registry through a validation process.
Methods:
Study I-II were national retrospective cohort studies of patients operated for colon cancer between 2007-2009. In study I, all patients radically resected for stage I-III colon cancer were included. In study II patients with stage I-IV colon cancer and acute large bowel obstrction managed with either BTS or ER with curative intent. Study III was a regional retrospective cohort study including patients that underwent emergency resection in 2011-2016. In study I-III data on short-and long-term outcomes were collected and analysed. Study IV was a validation study on 700 randomly selected patients operated for CRC in 2015. Data from the medical files were re-abstracted and compared with data in the SCRCR to assess the agreement.
Results: Postoperative complication is associated with decreased 5-year overall and 3-year disease free survival but not recurrence rate. BTS is associated with higher 5-year overall survival compared to ER, whereas no difference in the 3-year recurrence free survival. Specialization of surgical team dit not impact short-term outcomes, 3-year recurrence free survival or 5-year overall survival. Validation of register data showed almost perfect agreement of histopathology and recurrence data, whereas postoperative complication variables had moderate to substantial agreement depending on the severity of the complication.
Importance:
The results of this thesis shows that postoperative complications need to be addressed and treated promptly in attempt to increase survival. BTS has better overall survival and lower stoma rate and may be considered as a primary alternative in the management of malignang LbO. Acute care surgeons treat patient with emergent colon cancer with same result on long-time survival as colorectal surgeons. The validity of data in the SCRCR is very good but care must be taken when interpreting information on postoperative complications.