Colorectal Cancer ☺️ Flashcards
How does -cancer surgery -pelvic irradiation cause psychiatric symptoms -how could you manage this
Total gastrectomy/ileal resection/irradiation => B12 deficiency -tiredness -depression -forgetfulness B12 IM injections
2ww referral guidelines
Epidemiology
40+ - weight loss AND abdo pain
50+ - rectal bleeding
60+ Fe def anemia OR change in bowel habit
Occult blood of feces
Consider referral if
- rectal/abdo mass
- unexplained anal mass/ulceration
- U50 with rectal bleeding AND unexplained pain, change in bowel habit, weight loss, Fe def anemia
Describe the screening test for colorectal cancer
FIT test
- 2 yearly 60-74
- send stool sample - analysed for blood
- abnormal => colonoscopy
Also used for patients who do not meet 2ww criteria but have some symptoms
Risk factors
- environmental
- medical
- genetic
Protective factors
Pathophysiology
Age
Male
Environmental
- obesity
- red/processed meat, animal fat
- sugar, alcohol
Medical
- IBD (UC, Crohns)
- polyposis syndromes (Peutz Jehgers)
Genetic
- Hereditary (FAP, Lynch)
- Familial (sporadic)
Protective factors
- physical exercise
- calcium
- garlic
- non starchy veg and pulses
- fibre
Genetic susceptibility + tumourgenic lifestyle => hyperproliferation, adenoma => cancer
Lynch syndrome
- pathophysiology and genes
- clinical features
- diagnosis (Amsterdam criteria)
- management
Lynch - autosomal dominant
- MSH2/MLH1 affect MMR function => microsatellite instability
- high risk of endometrial cancer
Diagnosis
- 3+ family members with colon cancer
- span at least 2 gens
- 1 case before 50
Management
- 1-2 yearly colonoscopy from 25
- prophylactic surgery
FAP
- pathophysiology and genes
- clinical features
- management
FAP - autosomal dominant
- APC tumour suppressor function lost
- common in Ashkenazi Jew population
- 100s of polyps
Management
- Annual flexible sigmoidoscopy from 15
- if none found => 5 yearly colonoscopy from 20
Surgery
- polyps found = proctocolectomy + ileorectal anastomoses
- if rectal = proctolectomy + end ileostomy
Presentation of colorectal cancer in general
Changes in bowel habit
consipation/diarrhoea/increased frequency/straining
Rectal bleed => Fe def anemia
Abdo pain - bowel obstruction
Weight loss
History of IBD
Impact on other organs
- ureter obstruction => urinary retention
- fistula formation into bladder/stomach
Most common location for colorectal cancer
-How may the presentation of left and right colorectal cancer differ
Rectum and sigmoid
Right - more liquid
- Fe def anemia - slow prolonged blood loss => melena
- diarrhoea
- wider lumen = obstructive symptoms less common
Left/rectal - more solid
- CHANGE IN BOWEL HABIT
- bowel obstruction => peristalsis against mass (colicky pain => straining, bloody stool
- rectal mucous
Investigations
- gold standard investigations
- staging
- other blood tests
- tumour markers
GOLD STANDARD - colonoscopy => assess for synchronous cancer/polyps
-other options - double contrast barium enema, CT colonoscopy if obstruction found
Staging - CT chest, abdo, pelvis
Rectal - pelvic MRI to assess
-mesorectum
-Krukenberg tumours (ovary mets)
Blood tests
- FBC - Fe def anemia
- U&E, LFT - any mets/impact on function
- CEA - tumour marker for recurrence and follow up
Surgical management of colorectal cancer
- possible options and considerations you’d have to make
- what is the watershed area
- why is this important in a left hemicolectomy
Hemicolectomy and rejoin bowel + laparoscopic radical resection of lymphatic drainage
- lymphatics follow blood supply in colon => cut the blood supply of the affected area
- asc colon - resect branches of SMA
- desc colon - resect branches of IMA
- if unable to reattach bowel together => stoma
Watershed - region that is supplied by 2 different vessels
-rectosigmoid junction - IMA, int iliac
Surgical management of rectal cancer
Total mesorectal excision
-Lymph nodes here behind rectum
High up rectal cancer
- TME + colorectal anastomosis
- ileostomy - reduce severity of the consequences of stool leaking from the colorectal anastomosis
- once anastomosis has healed, ileostomy reversed
Low down rectal cancer
-abdominoperineal excision of rectum + permanent colostomy
Neoadjuvant chemo for high risk
Factors that affect where you site a colostomy
Abdomen shape
Type of clothes worn
Must be accessible to patient
Near rectus to prevent parastomal hernias
Caring for a stoma
- stoma bags
- life with a colostomy
- travel with a stoma
Supported by stoma nurse
- cleaning, looking after skin around colostomy
- change bag 1-3x day
- only discharged when confident in looking after colostomy
Contents can be soft/hard Bag has charcoal filter to absorb smell Should not leak Waterproof so you can swim and wash Carry spares just in case
Can return to normal, sexual activities
Avoid contact sports/heavy lifting
Special underwear and swimwear available
Use of the RADAR key for access to public disabled toilets
When to use a bowel anastomosis and when to use a stoma
Bowel anastomosis
- good blood supply
- no nutritional imbalances
- no shock, hypotension, ischemic bowel, tension, infection
If not => stoma
Differences in ileostomy and colostomy
Complications of ileostomy and colostomy
Ileostomy has spout => acid, digestive enzymes can drain without irritating skin
Colostomy does not
Both
- ischemia
- retraction/prolapse
- bleeding
- parastomal hernia
Ileostomy
-high output => dehydration, AKI, electrolyte imbalance
