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.
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
11.
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
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