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.
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.