COLORECTAL CANCER Flashcards
WHAT TYPE OF CANCER IS MAJORITY OF COLORECTAL CANCER?
Adenocarcinoma (start in mucus secreting cells) derived from epithelial cells lining colon or rectum
WHAT ARE THE RISK FACTORS FOR COLORECTAL CANCER?
1) Increasing age > 44 years old
2) Genetic mutations - APC or HNPCC
3) FHx
4) IBD
5) Low fibre diet
WHAT ARE THE CLINICAL FEATURES OF COLORECTAL CANCER?
1) Change in bowel habits - increase frequency, loose stool
2) Rectal mass
3) Rectal bleeding
4) Abdominal pain
5) Iron- deficiency anaemia
6) Weight loss - unexplained
7) Night sweats
WHAT ARE THE FEATURES OF RIGHT SIDED COLON CANCER?
1) Abdominal pain
2) Occult bleeding (blood in faeces that is not visible)
3) Mass in RIF
4) Anaemia
5) Present late
WHAT IS AFFECTED IN RIGHT SIDED COLON CANCER?
- ascending colon
- proximal 2/3rd of transverse colon
WHAT ARE THE FEATURES OF LEFT SIDED COLON CANCER?
1) Rectal bleeding
2) Change in bowel habits
3) Tenesmus
4) Mass in LIF
WHAT IS AFFECTED IN LEFT SIDED COLON CANCER?
- distal 1/3rd of transverse colon
- descending colon
- sigmoid colon
WHAT ARE THE DIFFERENTIAL DIAGNOSIS FOR COLORECTAL CANCER?
1) Haemorrhoids - PR bleed, altered bowel habits, weight loss but no abdominal pain
2) IBD - however younger age of onset
WHAT LABORATORY INVESTIGATIONS ARE THERE FOR COLORECTAL CANCER?
1) FBC (anaemia)
2) LFTs
3) Clotting factors
4) Carcinoembryonic antigen (CEA) - not diagnostic but monitors disease progression and treatment response.
WHAT LABORATORY IMAGING IS THERE THRERE FOR COLORECTAL CANCER?
1) Colonoscopy with biopsy
2) Flexible sigmoidoscopy - for fragile/ comorbid patients who can’t have 1
3) Staging investigations- CT scan (chest, pelvis, abdo) for distant metastasis and local invasion/ MRI rectum (rectal cancers).
WHAT STAGING SYSTEM IS USED FOR COLORECTAL CANCER?
- Duke’s TNM staging
WHAT IS INVOLVED IN THE SURGICAL MANAGEMENT OF COLORECTAL CANCER?
Suitable regional colectomy (remove primary tumour with adequate margin and lymphatic drainage), followed by primary anastomosis (join 2 ends of healthy bowel) or stoma formation (divert stool away from surgical area).
WHAT IS A RIGHT HEMICOLECTOMY AND WHEN IS IT USED?
- caecal or ascending colon tumours
- Removal of right side of colon (caecum, ascending colon and proximal 2/3rd of transverse colon)
- Ileocolic, right colic and right branch of middle colic vessels (branch of SMA) divided and removed with mesenteries
WHAT IS AN EXTENDED RIGHT HEMICOLECTOMY?
- performed for any transverse colon tumours
WHAT IS A LEFT HEMICOLECTOMY AND WHEN IS IT USED?
- descending colon tumours
- removal of descending and sigmoid colon
- Left branch of middle colic vessel, inferior mesenteric vein, left colic vessel divided and removed with mesentery
WHAT IS A SIGMOIDCOLECTOMY AND WHEN IS IT USED?
- sigmoid colon tumours
- IMA fully dissected with tumour
WHAT IS AN ANTERIOR RESECTION AND WHEN IS IT USED?
- high rectal tumours
- remove sigmoid colon and rectum
- leaves rectal sphincter intact
WHAT IS ABDOMINOPERINEAL RESECTION AND WHEN IS IT USED?
- low rectal tumours
- excision of sigmoid colon, rectum and anal sphincter
- permanent colostomy
WHAT IS HARTMANN’S PROCEDURE AND WHEN IS IT USED?
- emergency bowel surgery such as perforation or obstruction
- complete resection of recto-sigmoid colon and formation of end colostomy and closure of rectal stump.
WHAT ARE THE COMPLICATIONS OF THE SURGERY?
1) Adhesions leading to bowel obstruction
2) Hernia
3) Infection
4) Ileus - paralysis of bowel,
5) Anastomotic leak
6) Blood clots- DVT and PE
WHAT DOES THE SMA SUPPLY?
- organs of the midgut
- distal half of duodenum, ileum, caecum, ascending colon and proximal 2/3rd of transverse colon
WHAT DOES THE MIDDLE COLIC ARTERY SUPPLY?
- transverse colon
WHAT DOES THE RIGHT COLIC ARTERY SUPPLY?
- ascending colon
WHAT DOES THE ILEOCOLIC ARTERY SUPPLY?
- ascending colon, caecum, ileum, appendix
