Locally advanced rectal cancers (LARC) threaten the normal surgical margins and therefore needs neoadjuvant (chemo-) radiotherapy to down-stage the tumor before surgery. The Norwegian Radium Hospital Oslo University Hospital is a regional center for treatment of LARC in the south-eastern part of Norway and treat approximately 80-100 patients in this category annually. About 50 of these patients receive abdominoperineal resection (APR) as the main surgical treatment. A very high rate of deep surgical site infections is reported in the APR group internationally, particularly in the patients that have received chemo-radiotherapy. The knowledge of why these patients have such a high rate of infections is scarce.~Microdialysis is a technique which enables close to real-time monitoring of the tissues and organs of interest.~The investigators want to utilize the microdialysis method to describe and monitor metabolic and inflammatory parameters, after extensive oncological surgery for LARC in patients that have undergone chemoradiotherapy before surgery. With the knowledge of how the normal biology is, the investigators hypothesize that infection can be readily detected by the biomarkers retrieved by microdialysis.
The intention of the study is to explore metabolic and inflammatory parameters in the pelvis after abdominoperineal resection for locally advanced rectal cancer in patients that have received radiation therapy before surgery.