This document discusses colon cancer, including risk factors, pathogenesis, types of polyps, staging, and treatment. The main risk factors for colon cancer are age, personal history of colon cancer or inflammatory bowel disease, smoking, and obesity. Genetic defects like in the APC gene can cause familial adenomatous polyposis (FAP). Colon cancer is typically staged after diagnosis and treatment may involve surgery like colectomy along with chemotherapy and follow-up surveillance colonoscopies.

1. colon cancer
Dr. Ibrahim Albujays
31st Jan 2021
Almoosa specialist hospital

2. Incidince , risk factors , pathogenesis
Objectives
Polyps
Inherited colon cancer
Staging
Treatment

7. Risk
factors
Increase risk
 Age
 Personal hx ( colon ca.
, polyposis , IBD)
 Smoking
 Obesity
Decrease risk
 Dietry fibers
 Vitamin
 Good life style
 Antioxident

8. Pathogenesis
Genetic defect
Genetic pathway

9. Genetic defect
APC
Gene
K-ras
MYH
P53
PTEN
FAP
EGFR
AFAP
Cell apoptosis
Hamartomus
polyposis
syndrome

10.  80% of CRC
 Chromosomal
deletion
 APC with FAP
 Most of
remaining
 Error in
mismatch
repair during
DNA
replication
 Lynch 9
 Activate or
inactivate
 Serrated
polyps
Genetic pathway
Loss of heterozygostity Microsatellite instability Methylation

12.  25%
 >50 yrs
 Malignancy (size /types)
Neoplastic
 Small (<5 mm)
 Hyperplasia without dysplasia
 ? Removal
Hyperplastic
 WHO criteria
 Risk of malignancy 30%
Serrated
Polyps

13.  Not pre malignant
 Childhood
Hamartoma polyp (juvenile)
 Autosomal dominant
 Risk of malignancy
 Screening by age 10
Familial juvenile polyposis
 Infection
 Not pre malignant
 ?removal
Inflammatory (pseudopolyps)
and Against Argument

14.  Autosomal dominant
 Mutation in STK11
 Polyposis all GIT
 Skin manifestation
 Screening by age 20
Peutz jegur syndrome
 Non inherited disorder
 Mutation in PTEN
 Polyposis and alopecia
Cronkite Canada syndrome
 Autosomal dominant
 Mutation in PTEN
 Polyposis in colon and
stomach
 Breast and thyroid cancer
involved
Cowden’s syndrome

15. >100 syncrhonus
adenoma or < 100
with positive family
Hx.
 Autosomal dominant
 APC at 5q21
Surgical option
 Total proctocoletomy
with end ileostomy
 Total colectomy
 Proctocolectomy with
ileal pouch anal
anastomosis
Factors affecting treatment
 Age
 Presence of
symptoms
 Rectal polyps
 Presence of desmoid
FAP

16. Later presentation , fewer polyps
APC 30%
MYH mutation
AFA
P

17. Lynch syndrome HNPCC

19. Therapy
Stage 1, 2
• Surgical resection according to site
involved .
• Stage 2 , ( young patient , poorly
differntatied , lymphovascular
invasion , bowel perforation , in
adequate tumor margin) ,
adjuvant chemotherapy can be
added
Stage 3
• Post operative chemotherapy
• Oxaliplatin with fluropyramidine
(FOLFOX) for 6 months

20. Stage 4

21. Pre operative evaluation
• Looking for syncronus disorder
• CT abdomen , pelvis and chest
• CEA level
• In case of obstruction ,
gastrograffin can be used .

22. Surgical principles
1. Wide resection of involved colon +
lymphatics + mesocolon +enblock
resection of neiboghring
2. Margin around 5 cm is adequate
3. Mininmum of 12 LN for biopsy
4. Postive LN left beyond , consider
inproper resection
5. Inspect abdomen , viserca ,
peritoneum for any Mets
5
4
3
2
1

23. Surgical Options for Colon
cancer
1-Ca of cecum/ascending colon:
Right Hemicolectomy
2- Ca of hepatic flexure/proximal transverse colon:
Extended right Hemicolectomy
3-Ca of distal transverse colon:
Extended right Hemicolectomy including Splenic flexure OR left
Hemicolectomy
4- Ca of left colon:
Left Hemicolectomy
5-Ca of sigmoid colon:
Sigmoidectomy OR left Hemicolectomy

24. Specific consideration
 Right side /transverse : right
hemi , extending right hemi
Obstructing colon cancer
 Present with peritonitis
 Hartman is an option
Perforated colon cancer

25. Follow up
 History, physical examination &
S.CEA: every 3–6 month for 2 y,
then every 6 month for a total
of 5 yr
 Colonoscopy: In 1st yr:
Abnormal repeat in one yr.
Normal: repeat in 3 rd yr then
every 5 yrs If it was not done
before: 3-6 months post
surgery.
 CT scan chest & abdomen:
Annually for pts. with high risk
for recurrence(eg. poorly
differentiated tumors)
Survillance