colorectal carcinoma

epidemiology

3rd most common 3rd of this disease arise in rectum rare before 50( except in inherited colorectal

cancer syndromes) common after 60 other factor: diet(low fibre , high fat,red

meat,alcohol,) , diabetic, UC, inherited genetic condition

more common in developed (sporadic young indian subcontinent)

reduction in dss if taken aspirin

inherited condition causing bowel cancer

1.polyposis syndromes

2.hereditary non polyposis colorectal cancer (HNPCC)- low polyp but high risk to get CA

polyposis syndromes

• familial adenomatous polyposis (FAP)• AD in APC gene coz hundredss polyps develop

by mid teen.• develop CA at age 40• prevention : surgery in early adulthood 1.

(subtotal colectomy with ileorectal anastomosis) 2. (panproctocolectomy)

polyposis syndromes

peutz-jeghers syndrome develop hamartomas polyps throughout GI tract others features: freckles around mouth, hand,

feet, genitalia die at 50 because - bowel intussusception -

cancer cancer usually at

small/large/stomach/pancreas/testes and breast

HNPCC

Lynch syndromedefect in mismatch repair genes which mend

damaged DNA70% risk to get colorectal CAindicator cancer : endometrium/ ovary/

urothelium/ small bowel / brainwhen patient > 45 develop indicator cancer then

we test marker for genetic condition.

pathophysiology

• most CA initially exophytic(protrude into lumen) then ulcerated and progressively invade the muscular bowel wall. then eventually involved serosa and surrounding structures.

• stromal fibrosis cause luminal narrowing (IO) large bowel spread via lymphatic then blood

stream lymphatic 1-mesenteric node 2.para aortic

nodes( duodenal obstruction)(compress bile duct coz jaundice)

blood spread 1. liver

presentation

blood loss anaemiacaecum and asc colon rare cause obstructionpalpable mass in right iliac fossa change in bowel habitblood and mucus and loose stool large bowel obstruction(partial and complete) left colon because more solid

rectal bleed tenesmus perforation

SIGNcachexialow supraclavicular lymp node enlargemass/ liver/ ascitis rectal examination mandatory

Investigations

• Colonoscopy (best), look for synchronous lesions -Alternative: air contrast barium enema (“apple core” lesion) + sigmoidoscopy

• FBC• Metastatic workup: CXR, abdominal

CT/ultrasound• Bone scan, CT head only if lesions suspected• Labs: CBC, urinalysis, liver function tests, CEA

(before surgery baseline)

barium enema

capsule

staging

Treatment

• SURGERY (indicated in potentially curable or symptomatic cases -not always in stage IV)

• Curative: wide resection of lesion (5 cm margins) with nodes and mesentery

• Palliative: if distant spread, then local control for hemorrhage or obstruction• 80% of recurrences occur within 2 years of resection• Improved survival if metastasis consists of solitary hepatic mass that is

resected• Colectomy:• -most patients get primary anastomosis (e.g. hemicolectomy, low anterior

resection (LAR)-• -if cancer is below levators in rectum, patient may require an abdominal

perineal resection (APR) with a permanent end colostomy, especially if lesion involves the sphincter complex

• -complications: anastomotic leak or stricture, recurrent disease, pelvic abscess, enterocutaneous fistula

RADIOTHERAPY & CHEMOTHERAPY

• Chemotherapy (5 FU based regimens): for patients with node-positive disease

• Radiation: for patients with node-positive or transmural rectal cancer (pre ±post-op), not effective in treatment of colon cancer

• Adjuvant therapy –chemotherapy (colon) and radiation (rectum)

• Palliative chemotherapy/radiation therapy for improvement in symptoms and survival

Local Excision, Resection Anastomosis

Resection and Colostomy

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