Colorectal cancer, Colon, Rectum, Duke's staging, TNM staging, Astler-Coller classification, Hemicolectomy

1. COLORECTAL
NEOPLASMS
By
Dr. Abdul Qadeer
MBBS; FCPS; FICS
Assistant Professor in Surgery
King Faisal University College of Medicine

2. OBJECTIVES
1. Clinical anatomy of colon & rectum
2. Physiology of colon
3. Colorectal polyps
4. Adenoma-carcinoma sequence
5. Classification of colorectal cancer
6. Signs & symptoms
7. Causes
8. Pathogenesis

3. OBJECTIVES (CONTD….)
9. Diagnosis
10. Prevention: Lifestyle, medication, screening
11. Management: surgery, chemotherapy,
radiation, palliative care
12. Prognosis
13. Follow-up
14. Epidemiology

4. 1. CLINICAL ANATOMY OF COLON & RECTUM
 Large intestine (Colon & rectum) begins at ileo-
caecal valve and extends up to the anus
 Consists of:
1. Caecum (with appendix attached),
2. Ascending colon,
3. Hepatic flexure,
4. Transverse colon with attached greater
omentum,
5. Splenic flexure,
6. Descending colon,
7. Sigmoid colon and
8. Rectum (begins at sacral promontry)

6.  Transverse and sigmoid colon are mobile
 Ascending, descending colon and rectum are
fixed
 Apendices epiploicae
 Taenia coli
 Haustrations

8. ANATOMICAL RELATIONS
 Posterior relations of cecum & ascending
colon are:
1. Right ureter
2. Right gonadal vessels
3. Duodenum
 Posterior relations of left colon are:
1. Left ureter
2. Left gonadal vessels
3. Tail of pancreas

10.  Rectum is 12-18 cm long in adults, encircled
by the puborectalis muscle, creating an
anorectal ring (120o)
 It has three curves, 2 on right side and 1 on
left side
 Theses curves make semicircular folds
(Houston’s valves) from inside

12. ANATOMICAL RELATIONS OF THE RECTUM
 Its upper 1/3rd = peritoneum anteriorly +
laterally
 Its middle 1/3rd = peritoneum anteriorly
 Its lower 1/3rd = no peritoneum covering
 Anteriorly = prostate/vagina separated by the
Denonvilliers’ fascia
 Posteriorly = sacrum & coccyx separated by
Waldeyer’s fascia

13. BLOOD SUPPLY OF LARGE INTESTINE
 Branches of:
a) Superior and inferior mesenteric arteries
b) Marginal artery of Drummond
 Watershed area at the splenic flexure
renders it vulnerable to ischemic colitis
 Venous and lymphatic drainage of colon
follow the arterial supply
 Venous blood is drained into the portal
system

15. BLOOD SUPPLY OF RECTUM
1. Superior rectal artery: a direct continuation
of inferior mesenteric artery
2. Middle rectal artery: on each side from the
internal iliac artery
3. Inferior rectal artery: on each side from the
internal iliac artery
4. Upper ½: superior hemorrhoidal veins
superior rectal vein inferior
mesenteric vein
5. Middle rectal veins (unimportant)
occasionally exist

17. LYMPHATIC DRAINAGE OF RECTUM
 Follow the upward route of superior rectal
vessels (the inferior mesenteric vessels),
hence important for surgical clearance in
malignancy
 If it is blocked, then reverse flow may occur
to the nodes along with middle rectal vessels
or the inguinal region via inferior rectal
vessels

18. NERVE SUPPLY OF THE LARGE INTESTINE
 Sympathetic nerves via splanchnic nerves
surrounding the superior and inferior
mesenteric arteries
 Parasympathetic nerves via vagus and pelvic
splanchnic (S2-4) nerves

19. 2. PYHSIOLOGY OF LARGE INTESTINE
 Absorption of water is the principal function
of the colon
 Out of 1000 ml of ileal contents, 150-250 is
excreted as feces.
 Sodium is actively absorbed
 Chloride and water are passively absorbed
by the sodium pump
 A tiny amount of glucose, fatty acids, amino
acids and vitamins are also absorbed

20.  Dietary fiber is fermented by normal colonic
microflora (anaerobes e.g. bacteroides and
bifidobacteria) producing short chain fatty
acids (SCFAs) e.g. butyrate which provides
fuel for colonic mucosa
 Diversion of the fecal stream e.g. loop
ileostomy may cause diversion colitis

21. COLONIC MOTILITY
 It is variable
 Fecal residue reaches the caecum 4 hours,
and rectum 24 hours after meals
 Some residue may still be passed after 4
days through the rectum

22. 3. CLASSIFICATION OF INTESTINAL POLYPS
NO
.
TYPE OF
POLYP
EXAMPLE
1. Inflammatory Pseudopolyps in ulcerative colitis
2. Metaplastic Metaplastic or hyperplastic polyps
3. Hamartomatous Peutz-Jeghers polyp, Juvenile polyp
4. Neoplastic A. Adenoma i. Tubular
ii. Tubulovillous
iii. Villous
B. Adenocarcinoma
C. Carcinoid tumor

23. 4. ADENOMA-CARCINOMA SEQUENCE
 Colorectal cancer arises in a stepwise
progression from adenomas in which
increasing dysplasia in the adenoma is due
to an accumulation of genetic abnormalities.
 This is known as adenoma-carcinoma
sequence

25. 5. CLASSIFICATION OF COLORECTAL CANCER
 Mostly adenocarcinomas
 Rarely, carcinoid tumor, leiomyosarcomas
etc.
 Colorectal cancers are staged by:
 Duke’s staging
 Astler-Coller staging
 TNM staging
 It is also graded into low (well-differentiated),
average and high (undifferentiated)
histological grades

26. DUKE’S STAGING
STAG
E
DEFINITION PROGNOSIS
A The growth limited to the intestinal
wall
Excellent (90% year survival rate
B The growth is extended to the extra-
intestinal tissues
No metastasis to the regional lymph
nodes
Reasonable (70% year survival
rate)
C There are secondary deposits in the
regional lymph nodes
 C1: local pararectal lymph nodes only
involved
 C2: lymph nodes along the vascular
trunks are involved e.g. inf. Mesenteric
group
Poor (40% year survival rate)
D Distant metastasis e.g. hepatic

28. TNM STAGING
T N M
T1:
tumor invasion through the
muscularis mucosa but not
into the muscularis propria
N0:
No lymph node
involvement
M0:
No distant metastasis
T2:
Tumor invasion into but not
through the muscularis
propria
N1:
Between one & three lymph
nodes involvement
M1:
Distant metastasis
T3:
Tumor invasion through the
muscularis propria but not
through the serosa or
mesorectal fascia
N2:
Four or more lymph nodes
involvement
T4:
Tumor invasion through the
serosa or mesorectal fascia

29. 6. SIGNS & SYMPTOMS
 Age: usually above 55
 bleeding per rectum
 Sense of incomplete defecation:
tenesmus, spurious diarrhea, bloody slime
 Alteration in bowel habit: early morning
bloody diarrhea
 Pain: a late symptom
 Weight loss: suggests liver metastasis

30. 7. ETIOLOGY
 Adenoma-carcinoma sequence
 Mutation of APC gene, K-ras gene, p53 gene
 Diet: red meat, animal fat. Fiber is protective
 Smoking
 Alcohol
 Long-standing ulcerative colitis & Crohn’s
disease
 After cholecystectomy and
ureterosigmoidostomy?

31. 8. PATHOGENESIS
 Macroscopically: 4 forms
1. Annular
2. Tubular
3. Ulcerative
4. Cauliflower
 Microscopically:
1. Adenocarcinoma commonly
2. Lymphoma, GIST (leiomyosarcoma) rarely

32. SPREAD OF COLORECTAL CARCINOMA
1. Direct spread: longitudinal, transverse or
radial
2. Lymphatic spread
3. Hematogenous spread: commonly to the
liver, lungs, brian, bone, ovary, kidney are
rare
4. Transcoelomic spread: other structures
within the peritoneum e.g. omentum

33. 9. DIAGNOSIS / INVESTIGATIONS
 Screening: testing for fecal occult blood
followed by colonoscopy in 60-69 aged
people. A guaiac-based test is used which
detects the peroxidase like activity of fecal
hematin.
 Endoscopy: fiberoptic, flexible
sigmoidoscopy / colonoscopy ± biopsy
 Radiology: double-contrast barium enema
may show a filling defect. CT scan of
abdomen / chest

34. CONTRAST RADIOGRAPHY (APPLE-CORE
APPEARANCE)

35. 10. PREVENTION
 Change the dietary habits
 Quit smoking and alcohol
 Early diagnosis of intestinal polyps

36. 11. MANAGEMENT (SURGERY)
 Pre-operative preparation±
 Prevention of thromboembolism by anti-
embolic stockings or s/c LMW heparin
 Operations for colon:
1. Right hemicolectomy
2. Extended right hemicolectomy
3. Left hemicolectomy
4. Emergency surgery e.g. Hartmann’s
procedure

38. MANAGEMENT (SURGERY)
 Operations for rectum:
1. Anterior resection
2. Abdomino-perineal excision of the rectum
3. Endoluminal stenting
4. Palliative colostomy/laser
5. Pelvic exenteration (Brunschwig’s
operation)
6. Liver resection

40. MANAGEMENT (CHEMOTHERAPY)
 May be used combined with radiotherapy to
make the advanced tumor operable
 5-FU as adjuvant therapy in node-positive
disease (Duke’s stage C/N1,2). It may be
combined with oxaliplatin

41. MANAGEMENT (RADIOTHERAPY)
 Palliative irradiation for inoperable, painful
tumors
 Brachyradiotherapy

42. 12. PROGNOSIS (5-YEAR SURVIVAL RATE)
 Overall 5-year survival for colorectal cancer
is 50%
 Duke’s stage A: by surgical resection alone,
90%
 Tumor spread beyond the bowel wall: 60-
70%
 Tumor with lymph node metastasis: 30%
 Metastatic disease: 10%

43. 13. FOLLOW-UP
 Surveillance colonoscopy
 Regular imaging of liver (US, CTS) for
metastasis
 Measurement of CEA

44. 14. EPIDEMIOLOGY
 In UK, colorectal cancer is second most
cause of cancer death
 About 35000 patients are diagnosed with
colorectal cancer every year in UK; 1/3rd of
rectum and 2/3rd of colon
 M:F = same
 Less frequent in developing countries than in
industrialized countries