Colorectal Carcinoma Flashcards
Describe the aetiology of CC
Epithelial cells lining the colon or rectum, typically adenocarcinomas.
Progression of normal mucosa to colonic adenoma (colorectal polyps) to invasive adenocarcinoma. This is the adenoma-carcinoma sequence.
What are risk factors for CC?
Age > 60 Family history IBD Low fibre diet High processed meat intake Smoking High alcohol intake Genetic predisposition Previous cancer
What are the clinical features of left-sided CC?
Rectal bleeding, change in bowel habit, tenesmus, mass in left iliac fossa/mass on PR exam
What are clinical feature of right sided CC?
Abdominal pain, weight loss, iron-deficiencyanaemia, mass in right iliac fossa, occult (not visible) bleeding
When should patients be referred for urgent investigation?
40 or older with unexplained weight loss and abdominal pain
50 or older with unexplained rectal bleeding
60 or older with iron-deficiency anaemia or changes in bowel habit
Positive occult faecal blood test
Describe the colorectal cancer screening process.
Every 2 years to men and women aged 60-75
Faecal occult blood home testing kit, where 3 stool samples are required.
If an samples are positive, patients offered an appointment with specialist nurse and investigation via colonoscopy.
What investigations for CC?
FBC - microcytic anaemia (particularly if right sided)
U&E
LFT
Coagulation
Imaging:
Colonoscopy with biopsy
If patient is unsuitable - frailty, co-morbiditiy, intolerance - flexible sigmoidoscopy or CT colography
For staging:
CT (chest/abdo/pelvis) for metastases and local invasion
MRI rectum to assess depth of invasion of rectal cancers
Endo-anal USS
How can CC spread?
Local, lymphatic, blood (lung, liver,bone), transcoelomic
How is CC staged?
TNM - tumour, nodes, metastases
Dukes (A -beneath msucularis mucosa, B-through muscular mucosa, C -regional lymph node involvement, D - distant metastases
How is CC managed?
Surgery: regional colectomy to remove primary tumour with adequate margins and lymphatic drainage followed by primary anastomosis or formation of a stoma to restore function.
What is the treatment for caecal or ascending colon tumours?
Right hemicolectomy and extended right hemicolectomy
Ileocolic, right colic and right branch of the middle colic vessels from the SMA are divided and removed with their mesenteric
Extended for any transverse colon cancer
What is the treatment for descending colon tumours?
Left hemicolectomy
What is the treatment for sigmoid colon tumours?
Sigmoidcolectomy
What is the treatment for high rectal tumours?
Anterior resection - leaves rectal sphincter in tact and functioning if anastomosis performed.
What is the treatment for low rectal tumours?
Abdominoperineal (AP) resection
Permanent colostomy and removal of rectum and anas and distal colon
