Colorectal cancer is extremely common. Symptoms include blood in the stool and change in bowel habits. Screening using one of several methods is recommended for appropriate populations. Diagnosis is by colonoscopy. Treatment is surgical resection and chemotherapy for nodal involvement.

1. COLORECTAL
CANCER
MohmmadRjab Seder
2022

2. Learning Key-points
• Epidemiology of colorectal cancer in Palestine.
• Aetiologies and risk factors of colorectal cancer.
• Colorectal cancer genetics.
• How colorectal cancer develops?
• Types of colorectal cancer.
• Clinical features of colorectal cancer.
• Colorectal cancer imaging and staging.
• Screening and prevention.
• Lines of management.

4. What is Colorectal Cancer?
• Colorectal cancer starts in the colon or the rectum.
• These cancers can also be called colon cancer or
rectal cancer, depending on where they start.
• Colon cancer and rectal cancer are often grouped
together because they have many features in
common.

6. Colorectal Cancer (PMOH 2021)
• Is the second most common cancer in Palestine.
• The most common cancer among males.
• Incidence rate in West Bank: 16.4 per 100,000 population.
• 463 new cases.
Top 10 reported cancer per 100,000 population in West Bank

7. Colorectal Cancer Mortality (PMOH 2021)
Proportional distribution of the most reported cancer deaths of all
reported cancer deaths, West Bank, 2021
~ 177 case die each
year in West Bank due
to colorectal cancer

8. Aetiology
What Causes Colorectal Cancer?
• Inherited gene mutations
• Familial adenomatous polyposis (FAP).
• Gardner syndrome.
• Lynch syndrome (hereditary non-polyposis colon cancer or HNPCC).
• Peutz-Jeghers syndrome.
• MUTYH-associated polyposis (MAP).
• Acquired gene mutations
Most cases of colorectal cancer, the DNA mutations that lead to cancer are
acquired during a person’s life rather than having been inherited.

9. Genetics
• Colorectal cancer caused by DNA mutations that:
1. Turn on oncogenes. Or
2. Turn off tumor suppressor genes.
• Most due to sporadic mutations, but some due to known mutations.
• E.g., Adenomatous Polyposis Coli Gene (APC) … Tumor suppressor
gene.
• Other mutations:
• K-RAS
• P53

10. Risk Factors … (1)
Modifiable Risk Factors:
• Obesity.
• Low physical activity.
• Diet:
• Diet that’s high in red meat (e.g., pork, beef, liver).
• Processed meats (e.g., hot dog, luncheon meats).
• Low-fiber, high-fat diet.
• Cooking meat at very high temp.
• Low blood vit. D may increase the risk of colorectal cancer.
• Smoking.
• Alcohol use.
• Streptococcus bovis Bacteremia.

11. Risk Factors … (2)
Non-modifiable Risk Factors:
• Age > 50
• Hx of colorectal polyps or colorectal cancer.
• IBD – Crohn's dz, ulcerative colitis.
• A family history of colorectal cancer or adenomatous polyps.
• Having an inherited syndrome
• Lynch syndrome (HNPCC)
• Familial adenomatous polyposis (FAP)
• Peutz-Jeghers syndrome (PJS)
• MUTYH-associated polyposis (MAP)
• T2-DM
• Ethnicity – Africans Americans, Ashkenazi Jews.
Rarely
associated

12. How Does Colorectal Cancer Start?
• Most colorectal cancers start as polyps in the colon or rectum.
• Polyps can change into cancer over many years, but not all polyps
become cancer.
• There are different types of polyps.

13. How Colorectal Cancer Spreads?
• Direct extension (invasion) – though the wall of the colon/rectum.
• Blood circulation – to distant parts of the body (e.g., liver, lungs, …)
• Lymphatics – regionally.
• Transperitoneal and intraluminal.

14. Colorectal Polyps
• Adenomatous polyps (adenomas).
• Tubular
• Villous
• Tubulovillous
• Hyperplastic polyps and
inflammatory polyps.
• Sessile serrated polyps (SSP) and
traditional serrated adenomas (TSA).
Pre-cancerous
Not pre-cancerous

15. Types of colorectal cancer
• Adenocarcinomas (most common)
• Carcinoid tumors
• Gastrointestinal stromal tumors (GISTs) – not common in the colon.
• Lymphomas
• Sarcomas (rare)

16. Familial Adenomatous Polyposis (FAP)
• Rare autosomal dominant dz caused
by hereditary mutations in the APC
tumor suppressor gene.
• Characterized by hundreds or
thousands or polyps inside the colon
or rectum.
• Polyps may also form in the stomach,
jejunum, and ileum.
• ‫بهذا‬ ‫ينصابو‬ ‫راح‬ ‫األولى‬ ‫الدرجة‬ ‫من‬ ‫األقارب‬
‫المرض‬
100
.%
‫ف‬
‫ال‬
‫األقارب‬ ‫لكل‬ ‫نعمل‬ ‫زم‬
‫سنة‬ ‫كل‬ ‫للقولون‬ ‫ناظور‬ ‫األولى‬ ‫الدرجة‬ ‫من‬
.

17. Clinical Features
• Symptoms vary with the anatomic location of the tumor.
SYMPTOMS:
• A persistent change in your bowel habits.
• Melena or hematochezia / mucus in stool.
• Persistent abdominal discomfort (cramps, gas or pain).
• A feeling that bowel doesn't empty completely.
• Weakness or fatigue.
• Unexplained weight loss.

18. Diagnostics
• Fecal Occult Blood Test (FOBT)
• Fecal Immunochemical Test (FIT)
• Flexible Sigmoidoscopy
• Digital Rectal Exam (DRE)
• Carcinoembryonic Antigen (CEA)
• CT Colonography Every 5 y
• Colonoscopy
• Double Contrast Barium Enema
Screening
tools only

19. Fecal Occult Blood Test
‫البراز‬ ‫في‬ ‫الخفي‬ ‫الدم‬ ‫اختبار‬

20. Colonoscopy
Click to see a video

21. Double Contrast Barium Enema

22. Diagnosis Steps
• History and physical examination.
• Tests to look for blood in stool – FOBT, FIT, …
• Blood tests – CBC, liver enzymes, CEA.
• Diagnostic colonoscopy.
• Biopsy.
….…

23. Staging
• Clinical staging is done with:
• CT scan of chest, abdomen, and pelvis.
• Physical examination (ascites, hepatomegaly, lymphadenopathy).
• TNM system.
• T1-T4 indicates the depth of tumor penetration into the bowel wall.
• N0-N2 represents the involvement of regional lymph nodes.
• M0-M1 denotes the absence or presence of distant metastases.

24. Staging

25. 5-Year Survival Rates
For colon cancer
Stage 5-Year Survival Rate
Localized 91%
Regional 72%
Distant 14%
All stages combined 64%
For rectal cancer
Stage 5-Year Survival Rate
Localized 90%
Regional 73%
Distant 17%
All stages combined 67%

26. Lines of Management … (1)
1- Surgery for early-stage colon cancer
• Polypectomy
• Endoscopic mucosal resection
• Laparoscopic surgery
2- Surgery for more advanced colon cancer
• Partial colectomy
• Colostomy
• Lymph node removal
3- Surgery for advanced cancer

27. Lines of Management … (2)
4- Chemotherapy
5- Radiotherapy
6- Targeted drug therapy
7- Immunotherapy
8- Palliative care

28. Prevention/Screening
Can Colorectal Cancer Be Prevented?
• Avoid modifiable risk factors (high-weight, low physical activity, smoking,
alcohol consumption, high fat diet, processed meats, …)
• Colorectal screening for people ages >45 … protection for 10 ys.

29. Follow Up
• Stool guaiac test.
• Annual CT scan of abdomen/pelvis and CXR for up to 5 years.
• Colonoscopy at 1 year and then every 3 years.
• CEA levels are checked periodically (every 3 to 6 months).

30. Key points
• Colorectal cancer usually begins as a benign polyp that may develop on
the inner wall of the colon or rectum as people get older.
• Acquired mutations of colorectal cancer is commonest than inherited
mutations, and certain risk factors associated with acquired mutations.
• Gold standard diagnostic tool for colorectal cancer is colonoscopy.
• Preventive colonoscopy every 10 years is recommended for people >45y.

31. The End