Chapter 1 12 Significant improvements have been implemented in the surgical technique and total mesorectal excision has become the gold standard. Better surgical treatment, and the introduction of preoperative radiotherapy has led to a decrease in recurrence rates to 5-10 percent.3 Irradical resection, leaving tumour cells in the circumferential or distal resection margins, as well as incomplete resection of the mesorectum, have been identified as poor quality markers.7 Japanese studies have focused on the presence of positive lymph nodes in the lateral obturator and iliac fossae as a potential reason for local recurrence. It has been shown that most of these lymph nodes will be sterilized by pelvic external beam irradiation or chemoradiation.8 However, there is a renewed interest in these lymph nodes and their role in the aetiology of LRRC. Recent studies have shown that a substantial portion is not being eradicatedwith preoperative treatment, thus possibly needing surgical resection to lower the risk of lateral sidewall recurrences.9–11 Another pathway of development of local recurrence is exfoliation of tumour cells into the lumen.12 Migration of exfoliated tumour cells in peri-anastomotic abscesses or entrapment of these cells in the anastomosis can cause regrowth.13 Spillage of tumour cells in the operative field can be caused by advanced tumours breaking through the peritoneal surface, or by improper handling of the specimen during surgery.14 This type of recurrence follows the lining of abscesses or fistulas, or behaves in a multifocal pattern and can present as pelvic peritoneal carcinomatosis. Rarely, a recurrence is limited to the anastomosis itself, and more often the bulk of the recurrence lies perianastomotically. Regarding the treatment of LRRC, achieving a resectionwith clear margins is the single most important prognostic factor influencing survival. Achieving clear margins often presents a large challenge for the surgeon, and not achieving this can be considered as treatment failure. From an anatomical point of view, the pelvis is a dense structure comprising different compartments holding organs and structures.15 Modern rectal cancer surgery is based on removal of the rectal compartment with its mesorectal fascial lining and complete mesorectum by a so called total mesorectal excision (TME). After this kind of surgery for the primary tumour, the borders of these pelvic compartments have been distorted and even a solitary recurrence is likely to involve multiple compartments. To still achieve clear margins, resection will require extended procedures, and often an exenteration including resection of neural or bony structures is necessary. En-bloc resection and subsequent reconstruction can involve different specialties with extensive experience in this field.