The document provides an overview of colorectal cancer, detailing its types, risks, and treatment options, including familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (Lynch syndrome). It emphasizes the importance of surgical interventions to prevent cancer development, diagnosis through genetic criteria, and the necessity of regular surveillance in high-risk patients. Additionally, it discusses the epidemiology of colorectal cancer, the various diagnostic methods, and considerations for managing metastatic disease.

1. Carcinoma Colon
Dr Nataraj Y S
DEPT. OF SURGICAL ONCOLOGY
SIMSRC,Bengaluru

2. Anatomy of colon

4. Rectum

5. Blood supply of colon - Artery

6. Blood supply of colon – Venous

7. Lymph nodes

8. Layers of colon

10. TUMOURS OF THE LARGE INTESTINE
• Polyp
• a clinical description of any protrusion of the mucosa.
• It encompasses a variety of histologically different tumors.
• Polyps can occur
• single – BENIGN
• synchronously in small numbers
• part of a polyposis syndrome

11. Adenomatous polyp

12. Adenomatous polyp
• The tubular adenoma like a berry on a stalk
• The villous adenoma like a flat spreading lesion.
• The risk of malignancy developing in an adenoma increases with size
• There is a 10% risk of cancer in a 1-cm diameter tubular adenoma
• one-third of large (>3 cm) colonic adenomas will have an area of invasive
malignancy within them.
• Adenomas larger than 5 mm in diameter are usually excised because of
their malignant potential.

13. Snare polypectomy

14. Familial adenomatous polyposis
• Familial adenomatous polyposis (FAP) is defined clinically by the presence of more than 100
colorectal adenomas, but is also characterized by duodenal adenomas and multiple extraintestinal
manifestations

15. • Over 80% of cases come from patients with a positive family history.
• The remainder arise as a result of new mutations in the adenomatous
polyposis coli (APC) gene on the short arm of chromosome 5.
• FAP is inherited as an autosomal dominant condition
• Equal in men and women.
• The lifetime risk of colorectal cancer is 100% in patients with FAP.
• FAP can also be associated with benign mesodermal tumours such as
desmoid tumours and osteomas.
• Epidermoid cysts can also occur (Gardner’s syndrome)

16. • Carcinoma of the large bowel develops 10–20 years after the
onset of the polyposis.
• Malignant change is rare before the age of 20 years.
• If there are no adenomas by the age of 30 years, FAP is
unlikely
• Adolescence -surgery is usually deferred to the age of 17 or 18
years unless symptoms develop.
• Examination of blood relatives, including cousins, nephews and
nieces, is essential
• Referral to a medical geneticist is essential.
• If over 100 adenomas are present at colonoscopy, the diagnosis
can be made confidently

17. Treatment
• The aim of surgery in FAP is to prevent the development of
colorectal cancer.
• SURGERY - COLECTOMY

18. Hereditary non-polyposis colorectal
cancer
(Lynch syndrome)
• HNPCC is characterised by an increased risk of colorectal cancer and also
cancers of the endometrium, ovary, stomach and small intestine.
• It is an autosomal dominant condition caused by a mutation in one of the
DNA mismatch repair genes.
• The most commonly affected genes are MLH1 and MSH2.
• The lifetime risk of developing colorectal cancer is 80%
• The mean age of diagnosis is 45 years.
• Most cancers develop in the proximal colon.
• Females have a 30–50% lifetime risk of developing endometrial cancer.

19. Diagnosis - Amsterdam II criteria
• Three or more family members with an HNPCC-related cancer
(colorectal, endometrial, small bowel, ureter, renal pelvis)
• One of whom is a first-degree relative of the other two
• Two successive affected generations;
• At least one colorectal cancer diagnosed before the age of 50 years;
• FAP excluded
• Tumors verified by pathological examination
• Patients with HNPCC are offered regular endoscopic surveillance.

20. Carcinoma colon - Epidemiology
• Colorectal cancer is the second most common cause of cancer death.
• Approximately 35 000 patients are diagnosed with colorectal cancer every
year
• Approximately one-third of these tumours are in the rectum and two-thirds
in the colon.
• The burden of disease is similar in men and women.

21. Distribution of cancer

22. Adeno carcinoma sequence

23. Pathology

24. Staging colon cancer - AJCC 8TH
Edition

25. Metastasis

26. Clinical features
• 50 years of age
• Emergency presentation occurs in 20% of cases
• A careful family history should be taken.
• Those with first-degree relatives who have developed colorectal cancer before the age of 45 years
may be part of one of the colorectal cancer familial syndromes.
• Tumours of the left side of the colon usually present with a change in bowel habit or rectal bleeding,
• Right side lesion present later with iron deficiency anaemia or a mass
• Patients commonly present with metastatic disease.
• Lesions of the flexures may present with vague upper abdominal symptoms for many months
before symptoms suggestive of colonic disease appear

27. Investigation of colon cancer
• X ray barium enema
• CECT ABDOMEN
• Rigid sigmoidoscopy
• Flexible sigmoidoscopy
• Colonoscopy
• Virtual colonoscopy

28. X ray barium enema

29. CECT ABDOMEN

30. COLONOSCOPY

31. COLONOSCOPY

32. USES

33. VIRTUAL COLONOSCOPY

34. SURGERY- RIGHT HEMI COLECTOMY
• Carcinoma of the caecum or ascending
colon
• not to injure the ureter, gonadal vessels or
the duodenum.
• The ileocolic artery & right colic artery is
ligated
• Distal 20 cm of ileum and the mesocolon as
far as the proximal third of the transverse
colon is divided

36. Extended right hemicolectomy
• Carcinomas of the transverse colon and splenic
• The extent of the resection is from the right colon
to the descending colon.
• The mobilization is as for a right hemicolectomy
but dissection continues to take down the
splenic flexure and the whole transverse
mesocolon is ligated

37. Left hemicolectomy
• Sigmoid mesentery is mobilized
• Left ureter and gonadal vessels must be
identified and protected
• The splenic flexure may be mobilized
• The inferior mesenteric artery below its left colic
branch together with the related paracolic lymph
nodes is included in the resection
• Ligating the inferior mesenteric artery close to its
origin (‘high-tie’)
• A temporary diverting stoma may be fashioned
upstream, usually by formation of a loop
ileostomy

39. Surgery for FAP
• The aim of surgery in FAP is to prevent the development of colorectal
cancer.
• The surgical options are:
1 colectomy with ileorectal anastomosis (IRA)
2 restorative proctocolectomy with an ileal pouch–anal anastomosis (RPC)
3 total proctectomy and end ileostomy

40. Colectomy with ileorectal anastomosis
(IRA)

41. Restorative proctocolectomy with
an ileal pouch–anal anastomosis
(RPC)

42. Total proctectomy and end ileostomy

43. Emergency surgery
• Obstruction

44. Perforation

45. Treatment
• Surgery - a Hartmann’s procedure

46. Stenting

47. Metastatic disease
• Hepatic metastases can be resected and series have demonstrated 5-year
survival of over 30% in resectable disease
• Isolated lung metastases may occasionally be suitable for resection
• In patients with widespread disease, palliative chemotherapy is offered
alongside symptomatic treatment and support by a palliative care team.

48. FOLLOW UP
• Up to a half of all patients with colorectal cancer will develop
liver metastases at some point
• Regular imaging of the liver (by ultrasound and CT scan)
• Measurement of carcinoembryonic antigen (CEA)