After the preoperative evaluation of the disease stage, age of patient and expected remaining life span, general condition and comorbidity one of the following conditions are present:
- Expected curative situation – Curative treatment is started.
- Uncertain, potential curative situation – Curative treatment is started
- Definite uncurable situation – Best palliative treatment is started
- Independent of stage of the disease
- Fragile patient- Compromise – Customize treatment
- Very fragile patient – Only best supportive care
When curative treatment is intended all macro and microscopic tumor tissue must be surgically resected -R0 resection (R= residual tumor). There must be locoregionally free margins around the tumour and mesorectum and possible metastatic lymph nodes must be excised.
Cancer at a very early stage
T1 sm1- (possibly also sm2) in the rectum may be locally resected. This should be performed by transanal endoscopic microsurgery (TEM) by a well skilled surgeon.
T1 tumor on top of pedunculated polyps may be resected by snare, both in the colon and rectum.
Localized cancer (T1–T3 with or without lymph node metastases)
Cancer in the colon must be resected with removal of the tumor and 10 cm of the gut in each direction including the mesocolon and regional as well as central lymph nodes. Preoperative (neoadjuvant) treatment is unnecessary.
Stage III and high risk stage II patients shall have adjuvant chemotherapy for 6 months when the patient’s general condition can tolerate this.
Cancer of the upper and middle rectum require low anterior resection performed as total mesorectal excision (TME) according to Heald, with colorectal/-anal anastomosis or in some cases Hartmann’s procedure without anastomosis. When the distance from tumor of lymph node metastases to the mesorectal fascia is >2 mm no preoperative treatment is necessary while preoperative treatment should be givent for distances ≤ 2 mm.
Cancer in the lower rectum is ordinarily operated by rectal amputation (abdomino perineal resection - APR) with permanent end-sigmoidostomy. This should be performed as a cylindrical resection when the tumor threatens the margin of a standard APR.
Locally advanced cancer
T4 cancer of the colon, infiltrating neighbouring organs, is defined as locally advanced. Neoadjuvant treatment is not routine in Norway for such cases. The dissection must be performed outside the mesocolic plane when the tumor infiltrates through this, and adjacent involved organs must be totally or partly resected to obtain tumorfree margins. The area at risk of the resection margin, or where macroscopic tumor remains should be marked with clips for the identification at postoperative imaging and possible radiotherapy.
In the rectum T4 and T3 tumors closer than 2 mm from the mesorectal fascia are defined as locally advanced. Such patients are candidates for neoadjuvant treatment. Thereafter standard TME resection may be performed when this results in a R0 resection. If not, an extended TME must be performed. The tumor stage before the adjuvant treatment determines whether a standard or extended TME should be performed.