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1. COLORECTAL
CANCER
Dr. Aditya Singla
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2. Definition
 Malignant growth of tumor that begins from the inner
wall of the colon or rectum.
 Can also involve the anal canal.
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3. 22
ANATOMY

4. Anatomy
 The large intestine consists of the cecum; the ascending,
transverse, descending, and sigmoid colon; and the rectum
 Ascending colon (22% of colorectal carcinomas)
 Transverse colon (11% of colorectal carcinomas)
 Descending colon (6% of colorectal carcinomas)
 Sigmoid colon (55% of colorectal carcinomas)
 4 major tissue layers, from the lumen outward, form the large
intestine:
 The mucosa
 Submucosa
 Muscularis propria
 Serosa
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6. ASCENDING COLON

7. TRANSVERSE COLON

8. DESCENDING COLON

9. SIGMOID COLON

11. EPIDEMIOLOGY
 The 3rd most c ommon malignancy worldwide
 2nd most common cause of mortality in world
 Incidence and death rate stands at 13 th in
India
 The incidence is greatest among males
 Highest incidence rates in economically developed
countries
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12. Age & Colorectal CA
Relationship:
 An individual’s risk of developing cancer of the
colon or rectum increases with advancing age.
 The likelihood of cancer diagnosis ↑ after 40
years of age and rising progressively after age 50.
 The median age at diagnosis is 69 years.
 < 20%of patients are less than 50 years of age at
the time of diagnosis.
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13. Pathophysiology
 The formation of colorectal CA is a multistep process.
 Begins with an abnormal growth of tissue known as a
polyp (precursors to the disease) originating from the
innermost wall of the colon.
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14. ▶ The process of
transformation from polyp
to malignant disease
takes years.
▶ Once transformation
occurs, cancer begins to
spread through the wall
of colon/rectum.
▶ It can eventually invade
blood, L.Ns, or other
organs directly.
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A stalked colon
polyp

15.  95% are adenocarcinoma (glandular tissue).
 The disease can be prevented by removal of precancerous
tissue.
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16. Aetiology
 Aetiology is complex, involving:
 Patient- specific factors
 Environmental factor
 Genetic factors
 Genetic mutations associated with colorectal cancer:
 APC mutation/loss (Tumour suppressor gene).
 P53 mutation
 COX-2 overexpression (growth factor signalling
pathways)
 K-RAS mutation 35%, BRAF mutation 5% (oncogenes)
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17. Risk Factors
 Increase age: Age >50 (90%of patients)
 Male sex
 Family history.
 Personal history:
(history of colon polyps; multiple adenomas or size
≥10 mm)
 IBD (Ulcerative colitis, Crohn’s disease):
 ↑ 5- to 10-fold
 Risk ↑ with increasing extent of bowel involvement &
disease duration.
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18. Risk Factors
 Environmental factors/ Lifestyle:
 Physical inactivity & obesity
 Diet:
 fatty food
 Red meats
 processed meats
(hot dogs and some luncheon meats)
 low fibers
 Alcohol (excessive)
 SMOKING:
 Rectal > colon
 Dose relationship (pack/year)
 Duration
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19.  Particularly smoking in early life.
 As compared to never-smokers, the risks of
colorectal cancer and mortality in smokers were
18% and 25% higher, respe ctively.
 Early tobacc o use  influence risk of c ancer
recurrence and mortality among colon cancer
survivors.
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20. Risk Factors
 Genetic/Hereditary colon C A Syndromes:
 The 2 most common forms of hereditary colon
cancer are:
1. Familial adenomatous polyposis (FAP):
 Risk ↑ 100%
 AD
 Mutations of the adenomatous polyposis coli (APC)
gene
 0.2%to 1%of all colorectal cancers.
 Diagnosed by late teens or early 20s.
 Total colostomy is recommended when detected.
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21. 2. Hereditary non-polyposis colon cancer (HNPCC)/
Lynch Syndrome.
 AD
 2% to 4%
 MMR (mismatch repair) genes mutation in DNA.
 Diagnosed later in life as compared to FAP
 Tend to be located primarily in the right-sided (proximal
colon)
 Other factor can increase risk of colon cancer:
 DM (Type 2)
 in 15 studies (hyperinsulinemia & ↑ levels of free insulin-
like growth factor-1 (IGF-1), promote tumor cell
proliferation
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22.  Factors may ↓ colorectal C A risk:
 Fiber (Fruit & Vegetables)
 Physical activity
 Regular consumption of milk/Calcium & Vitamin D
(May have antiproliferative effects )
 Hormone replacement therapy (HRT). Persist over
10 y
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23. Signs & Symptoms
1. Subtle & nonspecific (generalised symptoms)
2. Asymptomatic (early stage).
3. **Persistent/sudden change in bowel habits:
(*Prolong constipation
*or diarrhea.
*pencil thin stool)
4. Bleeding from rectum or blood
In stool.
5. Vague Cramping or abdominal pain/discomfort,
bloating , N, V  2ndry obstruction, perforation,
bleeding.
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24. Signs and symptoms
6. Weakness and tiredness
(advanced stage).
7. Iron-deficiency anemia.
8. Unintentional weight loss
9. Increased liver enzymes
(sign of liver metastasis) (AST/ALT)
10. Hepatomegaly and jaundice
in advanced disease.
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25. SYMPTOMS

26. Symptoms 20

27. DIAGNOSIS
 Signs and symptoms
 Entire Large bowel evaluation:
 Colonoscopy
 Double-Contrast Barium Enema
 CT Colonography (detect adenomas at least 6 mm).
 Flexible sigmoidoscopy (FSIG) : examine lower half of
the bowel to the splenic flexure, capable to detect
50%-60% of CA.
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28. DIAGNOSIS 25

29.  Biopsy
(during colonoscopy)
 Ultrasound: Determines
depth of tumor penetration,
assessing L.Ns
 CT scan: same as ultrasound +useful in assessing for
metastasis
 Blood tests: bld count, PT, PTT
, Liver function test.
 CEA (carcinoembryonic antigen)Tumour marker
 Non-sensitive, non specific in early stage
 Usually elevated in metastatic or recurrent colon C A
 Normal 0-3 ng/mL
 Monitor the recurrence.
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30. SCREENING
 Often same as diagnosis
 Colonoscopy: gold standard for colorectal
screening
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31. SCREENING
A. Colonoscopy/ Barium enema/ CT scan
(alternative for individuals who don’t wish to
undergo /not suitable for colonoscopy.)
B. CEA level
C. Fecal screening test:
1. Fecal occult blood testing (FOBT)
 Many early-stage tumors do not bleed.
 High false -ve rate
 Sensitivity 33-75%
 Increased sensitivity & specificity when used in
combination with test 2
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32. 2. Fecal immunochemical test (FIT)
 Can be used to replace FOBT
 Sensitivity 60-85%
 Specific ity > 97%
 No drug or food interactions
 Uses ABs to detect globin protein Hg in stool
D. Digital Rectal Exam (DRE):
Can detect anorectal
palpable mass
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33.  Screening guidelines for early detection of colorectal
CA with the goal of cancer prevention:
Risk Screening recommendation
Average risk
(R.F ≥ 50 ys)
both M/F
 Annual DRE and FOBT/FIT and one of the following:
– Sigmoidoscopy every 5 years
– CT colonography every 5 years
– Colonoscopy every 10 years
– Barium enema every 5 years
Family History Begin screening at age of 35-40 years or 10 years younger from
first-degree relative colorectal cancer diagnosis
IBD Begin screening at 8–15 years after diagnosis
FAP Begin screening at 10-12 years
HNPCC Begin screening at age of 20–25 years or 10 years younger
from 1st-degree relative colorectal CA diagnosis
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34. 32

35. Copyrights apply

37. Treatment
I. Surgery
II. Radiation
III. chemotherapy
IV. Targeted molecular therapies.
 Treat Depend on the location & extent of disease.
 Prognosis depend on extent of tumour
penetration/LNs involvement, Metastases.
 Goals:
 Curative therapy for localized C A
 Palliative therapy for metastatic CA.
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38. Treatment
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 Surgery in CA of the colon or rectum (stage, I, II,III):
 Complete surgical resection of the primary tumor
mass with regional lymphadenectomy
 At least a 5 cm margin of tumor-free bowel &
regional lymphadenectomy
 Selected patients with resectable metastases,
surgical resection may be an option.

39. Treatment
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 If the distal margin clear of tumor is at least 1 cm,
sphincter-preserving surgery may be possible for
patients with CAs in the middle and lower portion of
the rectum (LAR)
 If not C a ndidate for sphincter-preserving surgery 
Abdomino-perineal resection (APR) = remove distal
sigmoid, recto-segmoid, rectum, anus.
 Colostomy (after colectomy) has become an
accepted procedure for colon and rectal cancer.

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 Rectal C A is more difficult to resect with wide margins.
 Local recurrence of rectal C A is more common
compared to colon C A
 If lies closer to the a nal sphincter, so the risk of
localized treatment failure & recurrence at the initial
site of disease is increased
 Radiation (XRT) is usually reserved for rectal cancer
 Adjuvant XRT +chemo. are standard for stage II/III
rectal C A
 Neo- Adjuvant therapy before rectal surgery to:
Shrink the tumour & make it resectable, prevent local
recurrence in rectal CA.

42. Stage Management
Stage I Surgery
Stage II Colon: Surgery (observation +/- chemo.)
Rectal: Surgery + XRT + chemo.
Stage III Colon: Surgery + Chemotherapy
Rectal: Surgery + XRT + chemo.
Stage IV +/- surgery (selected pt.)+ chemo. + MoAB ,
Palliative care
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43. SURVIVAL :
 5-year survival rate:
Disease Stage 5- Year
survival
Early stages (localized/stage I, II) of colon 91 %
Early stages rectal cancer. 88%
Regional disease/Stage III:
Colon & rectal cancer after the tumor has spread
regionally to adjacent LNs or tissues
70%
Metastatic disease ≤ 12%
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