The treatment of rectal cancer is complex and comprises: diagnostic measures; different preoperative treatments; a multitude of surgical and technical choices; possibilities of postoperative treatments and postoperative care and follow up. In this thesis, some aspects of this complex paradigm have been further investigated. One of the most feared complications after rectal cancer surgery is anastomotic leakage. The risk of anastomotic leakage is affected by non-influenceable factors related to the tumour and the patient. In the first paper, the risk of anastomotic leakage in relation to a surgical instrument, the circular stapler, was investigated. The risk of leakage was 7% or 11%, depending on the choice of instrument. In the second paper, a long-term evaluation of survival and local recurrence rates in the Swedish Rectal Cancer Trial was made. Randomisation was to either preoperative radiotherapy followed by surgery or surgery alone. After 13 years median follow-up, survival was 38% in the radiotherapy group and 30% in the surgery alone group. Differences in local recurrence rates were seen in all stages. Most rectal cancer operations carry a high risk of morbidity and mortality. For early stage cancers, a local procedure may be sufficient and in the third paper, population-based results of local excision of rectal cancer were explored. In stage I, cancer specific survival was the same after local excision as after major resection, but the relative survival was lower. The risk of local recurrence was higher after local excision than after resections. In the fourth paper, differences in survival rates in the Nordic countries and Scotland were investigated. The relative excess risk of death was highest in Denmark, but only in the first 90 postoperative days.
Through applying already existing knowledge and successively introducing new treatments, the results for rectal cancer treatment will be further improved.