Colorectal cancer

Essentials

• Do not hesitate to refer patients with abdominal symptoms for further examinations. The reason for haemorrhage in the intestinal canal must always be identified by endoscopy.
• Diagnosis is usually made by colonoscopy and biopsies, sometimes by CT.
• After detecting a tumour, the patient must be referred urgently to a surgical unit. At this stage, waiting for biopsy results may cause unnecessary delay.
• Colorectal cancer can be cured by surgery. The earliest possible detection will ensure the best treatment results.
• Postsurgical follow-up is done to look for any recurrence. Surgical treatment of a recurrence can improve the prognosis and, in the best case, provide curative treatment.

Prevalence and aetiology

• In Finland, about 2 600 new cases of colorectal cancer are diagnosed each year.
• The incidence is continuously increasing, representing the third and second most common forms of cancer in men and women, respectively, in Finland.
• About 40% of all cases occur in the rectum and 60% in the colon. For the percentage distribution of colorectal cancer in the intestine, see picture .
• Originates in adenomatous polyps that should be removed. Endoscopic follow-up should be arranged for these patients.

Symptoms

• It should be remembered that the disease may remain completely asymptomatic for a long time.
• Typical symptoms include overt or occult bleeding, anaemia, change in bowel movements (e.g. diarrhoea or constipation), abdominal pain and weight loss.

Examination

• The faecal blood test is only meant for centrally organized screening of people with no symptoms. A positive result in the faecal blood test must lead to colonoscopy. Those with symptoms must be examined by digital rectal examination and colonoscopy.
• Haemorrhoids cannot be confirmed as the cause of bleeding unless colonoscopy up to, at least, the sigmoid colon has been performed.
• Colonoscopy and biopsies are the most important examinations and form the basis for diagnosis. In some cases, e.g. in emergencies, a CT finding is sufficient.
• If a suspicious tumour is detected by colonoscopy, the patient must be urgently referred to a surgical unit. Tumour staging can initially be based on suspicion. To avoid any delay, biopsy results can be sent later.
• Carcinoembryonic antigen (CEA) is suitable for the follow-up of cancer; it is a not a screening test for bowel cancer.

Examinations in a surgical unit

• CT scanning of the body or, alternatively, abdominal ultrasound and chest x-ray, are used for staging.
• In rectal cancer, additionally rectal MRI or anal ultrasonography to define local spread

Classification and prognosis

• TNM classification is the most exact. Dukes' classification is still often used in addition.
  • Classification is based on examination of the whole surgical specimen and the lymph nodes in it and consideration of metastases identified during operation or by imaging.
  • The number of examined lymph nodes has been shown to have prognostic relevance (recommendation > 12 lymph nodes).
• The prognosis and assessment of the probability of recurrence are based on TNM classification (T = depth of tumour invasion, N = metastases in mesenteric lymph nodes, M = metastases). In addition, the prognosis can be roughly determined on the basis of the grade of differentiation (poor, intermediate, high) together with certain other morphological prognostic factors (blood vessel and nerve invasion).
• See table .

Treatment

• Surgery is the only curative treatment, and it can be performed either by an open technique or by laparoscopy. In the surgical operation, the tumour-bearing intestinal section and the mesentery are resected.
• Typical operations for colonic cancer include right hemicolectomy, left hemicolectomy and sigmoid resection. In rectal cancer, anterior resection and abdominoperineal resection including resection of the anus are used.
• In surgical treatment of colonic cancer, no stoma is usually needed. In surgical treatment of distal rectal cancer, either a permanent stoma or a temporary protective stoma may be needed.
• In rectal cancer, preoperative radio- or chemoradiotherapy is sometimes given (T3–T4 tumours).
• Stage III (Dukes C) patients are routinely given postoperative adjuvant chemotherapy because it has been found to improve their prognosis. For Stage II (Dukes B) patients, adjuvant chemotherapy is performed only as considered appropriate if the patient has risk factors (e.g. T4 tumour, blood vessel or nerve invasion, or if the operation is performed as an emergency procedure due to perforation).
• Some patients with rectal cancer are given postoperative radiotherapy.
• Cytotoxic treatments have been able to reduce single metastases of colorectal cancer briefly but permanent cure can only be achieved by surgical resection of the metastasis.
• If the disease has spread beyond the reach of radical surgery, palliative oncological treatments and palliative surgery must be resorted to. In these patients, the mean period of survival is approximately 2 years.

Follow-up after surgery

• Follow-up after surgery has been shown to improve the prognosis . So far, there are no research data showing the optimum follow-up frequency or methods.
• The aim of follow-up is to look for single local recurrences or metastases. Surgical treatment of these can be used to improve the prognosis.
• Follow-up should be arranged for patients who have undergone radical cancer surgery and whose condition allows repeat surgery or cytotoxic treatments.
• In addition, it is important to look for new intestinal tumours in patients who have previously undergone surgery for colorectal cancer.

Follow-up examinations

• Follow-up visits usually take place every 3 months for the first 2 years and then every 6 months for a total of 5 years.
• Follow-up visits should include clinical examination including digital rectal examination and palpation of the perineum.
• CEA should be determined in connection with every follow-up visit.
• Abdominal imaging (ultrasound or CT) is usually performed after 1(–2) year(s).
• Endoscopic examination of the remaining intestine should be performed 1–2 times during follow-up. However, the endoscopic examination should be performed 6 months after surgery already if the total intestine has not been examined endoscopically before surgery.
• In some follow-up programmes after rectal cancer, the anastomosis area is examined endoscopically every 6–12 months during the first 2 years.
• After the 5-year follow-up, endoscopic examination of the remaining intestine to detect any new tumours should be arranged for patients under 65 years approximately every 5 years until the age of 70.
• If recurrence or metastasis is suspected, the patient should be referred to a surgical unit.

Follow-up at health centre

• It should be assessed whether the patient's general condition would allow surgical resection or oncological treatment of any tumour recurrence. If treatment is not considered possible, cancer follow-up is not justified. For such patients, follow-up by their own health centre physician taking into account their overall situation is the most sensible choice.
• The patients should visit their physician as required by their condition, and no actual follow-up examinations will be needed.

Follow-up schedule

• See Table .

Related resources

• Cochrane reviews
• Other evidence summaries
• Literature