Colorectal Flashcards
Risk factors for colorectal cancer
Family history of bowel cancer
Genetic
- Familial adenomatous polyposis (FAP) – a genetic condition causing polyps throughout the bowel
- Hereditary nonpolyposis colorectal cancer (HNPCC/ Lynch syndrome)
IBD
Increased age
Diet - high in red and processed meat and low in fibre
Obesity and sedentary lifestyle
Smoking
Alcohol
Presentation of bowel cancer
Change in bowel habit - usually more loose and frequent stools
Unexplained weight loss
Rectal bleeding - frank or melaena
Tenesmus
Unexplained abdo pain
Iron deficiency anaemia - microcytic anaemia with low ferritin
Abdo or rectal mass on examination
2 week wait criteria for bowel cancer
40 and over with unexplained weight loss and abdo pain
50 and over with unexplained rectal bleeding
60 and over with
- iron deficiency anaemia
- change in bowel habit
Tests show occult blood in faeces
Presentation of bowel obstruction
Vomiting
Abdo pain
Absolute constipation
Features of bowel cancer screening
Faecal immunochemical tests (FIT) look at amount of human haemoglobin in stool
- replaced faecal occult blood test - could give false positives due to blood in foods
- used in GP for patients who do not meet 2 week referral
- used for bowel cancer screening - those 60-74 sent home kit every 2 years
Those with risk factors such as FAP, HNPCC or IBD offered colonoscopy at regular intervals to screen for bowel cancer
Ix for bowel cancer
Colonoscopy - gold standard
- lesions biopsied or tattooed in prep for surgery
Sigmoidoscopy
- used in cases where only feature is rectal bleeding
CT colonography
- CT scan with bowel prep and contrast
- considered for patients less fit for colonoscopy
- less detailed and no biopsy
Staging CT
- full CT thorax, abdo and pelvis
Carcinoembryonic antigen (CEA) is a tumour maker
- not helpful in screening
- used for predicating relapse
Classification of bowel cancer
Dukes A – confined to mucosa and part of the muscle of the bowel wall
Dukes B – extending through the muscle of the bowel wall
Dukes C – lymph node involvement
Dukes D – metastatic disease
TMN for bowel cancer
Tumour - TX – unable to assess size - T1 – submucosa involvement - T2 – involvement of muscularis propria (muscle layer) - T3 – involvement of the subserosa and serosa (outer layer), but not through the serosa - T4 – spread through the serosa (4a) reaching other tissues or organs (4b) Nodes - NX – unable to assess nodes - N0 – no nodal spread - N1 – spread to 1-3 nodes - N2 – spread to more than 3 nodes Metastasis M0 – no metastasis M1 – metastasis
Mx of colorectal cancer
MDT Surgical resection - limited mets Chemotherapy - 5-FU - capecitabine - irinotecan - oxaliplatin Radiotherapy - neoadjuvant or adjuvant - palliative Biological/target therapy - advanced disease - anti-EGFR - cetuximab Palliative care
Features of surgical resection
Aim to remove entire tumour - curative
Can be palliatively to reduce size of tumour and reduce symptoms
Laparoscopic gives better recovery and fewer complications
Types of surgical resection
Right hemicolectomy
- removal of caecum, ascending and proximal transverse colon
Left hemicolectomy
- removal of distal transverse and descending colon
High anterior resection
- removal of sigmoid colon
Low anterior resection
- removal of sigmoid colon and upper rectum but spares lower rectum and anus
Abdomino-perineal resection (APR)
- removal of rectum and anus suturing over anus - leaves patient with permanent colostomy
Hartmann’s procedure
- emergency procedure - acute obstruction by tumour or significant diverticular disease
- removal of rectosigmoid colon and creation of colostomy
- rectal stump sutured closed
- can be reversed later
Complications of surgical resection
Bleeding, infection and pain Damage to nerves, bladder, ureter or bowel Post-operative ileus Anaesthetic risks Laparoscopic surgery converted during the operation to open surgery Leakage or failure of the anastomosis Requirement for a stoma Failure to remove the tumour Change in bowel habit Venous thromboembolism (DVT and PE) Incisional hernias Intra-abdominal adhesions
Define low anterior resection syndrome
Disordered bowel function after rectal resection
Portion of bowel from rectum anastomosis between the colon and rectum
Clinical features of low anterior resection syndrome
Urgency Frequency Loose stools Incomplete evacuation Fragmentation of stools Incontinence Tenesmus
High risk patients for low anterior resection sydnrome
Low anastomosis Radiotherapy Ileotomy for more than 12 weeks Age over 75 years Pre-existing bowel dysfunction
