Computer Navigation-assisted Surgery for Locally Advanced and Recurrent Rectal Cancer (NAVI-LARRC)

The aim of this study is to investigate feasibility of computer navigation-assisted surgery in particularly difficult cases of locally advanced (LARC) and recurrent (LRRC) rectal cancer where the standard surgical strategy is expected to result in incomplete tumour removal. The investigators hypothesize that computer navigation-assisted surgery can facilitate improved anatomic orientation in the pelvis enabling tumour removal with free margins in these cases.

Curative treatment of rectal cancer requires surgical removal of the tumour. The key challenge in this surgery is to remove the tumour with free margins - R0 resection. Failure to achieve R0 resection often leads to recurrence, which is associated with risk of long-term suffering, poor quality of life and death for the patients. Achieving R0 resection is most difficult in advanced rectal cancer cases, where the tumour is threatening - and sometimes even growing into - neighbouring organs. Computer navigation-assisted surgery has typically been implemented where extreme surgical precision is necessary or in surgical fields with high anatomic complexity. In such settings, it contributes to preservation of vital anatomic structures close to the tumour, and ensures completeness of resection in cases of malignant disease. With this in mind, feasibility of navigation in surgically challenging rectal cancer cases will be investigated in this study. If found feasible, navigation could improve surgical management for patients who otherwise would not have the possibility of cure.

Computer navigation-assisted surgery has two main elements; the pre-procedural planning to create accurate 3D images of the pelvis allowing the surgical team to achieve an accurate perception of the operative field, and intraoperative navigation where these images are used for anatomical guidance to enhance surgical precision. Accordingly, computer software is used in this study to outline the tumour and other pelvic organs on pre-operative images which are subsequently used for intraoperative navigation.

Assessment of whether pre-procedural plan was executed during surgery by comparing pre- and post-operative magnetic resonance imaging (MRI).

Postoperative MRI of the pelvis will be examined and compared to preoperative MRI to evaluate what structures were removed at surgery.

Assessment of whether pre-procedural plan was executed by comparing volume of intended resection with volume of resected specimen.

Volume of intended resection (measured in millilitres) based on pre-procedural MRI will be comparted with volume of resected specimen (measured in millilitres).

Interviews with the surgeons will be semi-structured based on an interview guide. They will be recorded and transcribed, and analyzed using thematic analysis.

Occurrence of 30 day morbidity and mortality assessed with the Accordion severity grading system of surgical complications

The Accordion severity grading system of surgical complications classifies surgical complications in 6 Levels ranging from mild complications (1) to Death (6)

Assessment of patients quality of life using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)

The EORTC QLQ-C30 comprises 30 items (i.e. single questions) registering five functioning scales (physical, role, cognitive, emotional and social), three symptom scales (fatigue, pain and nausea/vomiting) and one global health status scale. EORTC QLQ C30 will be completed prior to surgery, and at one and three years after surgery. Changes over time will be analysed.

Inclusion Criteria: Patients with LARC or LRRC (either biopsy verified, or demonstrated on MRI and confirmed by the MDT decision) The MDT must deem standard surgical strategy at high risk of resulting in R1/R2 resection and computer-assisted navigation likely to improve the chances of obtaining R0 resection. Written informed consent Exclusion Criteria: Non-adenocarcinoma malignancies. Unresectable distant metastatic disease or unresectable synchronous other malignancy Patients deemed unfit to participation according to the MDT.