Colon Cancer + Anorectal Cancer Flashcards
What is the most common colon cancer and where does it affect
Adenocarcinoma
Rectum + sigmoid
Other - HNPCC / FAP
What is an adenoma (polyp) and types
Benign
Pre malignant
Tubular (75%)
Villous (10%)
What are high risk polyps
Large
Numerous
High risk dysplasia
Villous archiecture
How does colon cancer develop
Activation of oncogenes (K-ras, c-myc)
Loss of tumour suppressor genes - APC / p53
Defective DNA repair
What are the RF for colon cancer
Age Male Smoking Alcohol DM FH Diet Previous adenoma Genetics - HNPCC / FAP Neoplastic polyps IBD
What are high risk features of bowel cancer
Bowel habit change > 6 weeks Rectal bleeding with NO anal symptoms Persistent abdo pain >6 weeks Unexplained anaemia MAss Anaemia - unexplained Loss of appetite Bloating / IBS Sx Weight loss + abdominal pain >40 FOB found on test Clinical doubt
Having diarrhoea at night = abnormal
What do high risk features automatically get
Colonoscopy +- biopsy
Can do sigmoid but only up to sigmoid - if fresh bleed
What do R sided (ascending) colon cancer normally present with
Anaemia due to occult bleed Change in bowel habit >6 weeks - Increased frequency - Increased consistency = more common Weight loss Vague pain Weakness Present later as lumen can get very tight before obstruction as more liquid BEWARE APPENDICITIS - tumour can obstruct appendix or can perforate and give appendicitis picture - do CT scan in all >40
What does L sided (descending) colon cancer present with
More common Obstruction - can present Stricture / perforation / fistula Bleeding / mucous PR due to haemorrhage Altered bowel habit Weight loss / lethargy Tenesmus - need to evacuate Mass Perforation Anaemia = rare as will present early with bleed
What are common symptoms in bowel cancer
Persistent blood Persistent change in bowel habit Persistent lower abdominal pain Anaemia Loss of appetite Bloating Mass Can have emergency presentation - Perforation - Obstruction
What do you do if symptoms <6 weeks + <40
Watch and review
What other investigations for colon cancer
How do you stage
CT colonography if unfit for colonoscopy (6 months post MI / COPD)
- Bowl prep and air inflation required
FOB / qFIT - before colonoscopy
Bloods - FBC, U+E, LFT, TFT, coeliac, Ca, calprotectin - differentials, full iron
Urine dip - as 1% of qFIT due to renal haematuria
Staging CT - CAP with contrast MRI if below peritoneal reflection Liver MRI / USS PET if single met but chance of cure
What are the stages of colon cancer
Dukes criteria or TNM T1 A- mucosa T2 B- muscle T3 C- LN T4 D- metastatic
AJCC Stage 1 = early (T1/2) Stage 2 = no nodes (T3/4) Stage 3 = no mets (any nodal spread) Stage 4 = mets (any mets)
How do you treat Dukes A
Endoscopic resection
Remove node for analysis
DVT and Ax prophylaxis
How do you treat more advanced cancer
MDT
Chemotherapy given after and before
Radiotherapy - palliation mostly or for rectal net-adjuvant
Surgery = only way to cure
NSAID - reduce polyps and prevent recurrence
Biologics in combination with chemo
What are the complications of surgery
Anaeshtetic issue Bleeding Infection / sepsis Pain Nerve or vessel damage Damage to ureter / bowel DVT Wound hernia / dehiscence Obstruction Post op ileus - give sugar before Anastomatic breakdown - day4-5 Post op fistula Post op stricture Adhesions High output stoma = volume deplete/ electrolyte imbalance
What is the screening programme for bowel cancer
50-74 FOBT / qFIT every 2 years If +Ve = colonoscopy Recognises Hb Different if FAP etc
What is FAP
Autosomal dominant APC mutation (tumour suppressor)
Annual colonoscopy from age 10
Prophylactic protocolectomy at 16
What do you get if you are HNPCC +Ve
AD mutation in DNA mismatch repair gene
2 year colonoscopy from 25
Endometrial / colon cancer / ovarian / pancreatic
What do you get if you have IBD
Colonoscopy 10 year post diagnosis
What is considered high risk FH
Colon cancer in 3 FDR
5 year colonoscopy at 55
What do you get if low risk
Single colonoscopy at 55
Where does colon cancer spread too
Local
Lymphatic
Blood - liver = most common, lung, bone
Transcoelomic
What factors play a role in whether anastomose or stoma
Blood supply - e.g. PVD will most likely have stoma
Tissue tension
Sepsis
Unstable patient
Where is an ileostomy typically
R iliac fossa
Stump
Emit frequent fluid motion with active enzyme so need to protect skin
Same with urostomy as urine = toxic
Where is a colostomy
L iliac fossa
Flatter stump as not as acidic to skin - this tells you what it is rather than side
Solid faeces inside
If need replaced will be on different sides
What are palliative options
Chemo / RT
Diversion stoma
COlonic stenting
When would you do endoscopy / colonoscopy
Unexplained iron deficiency as risk of malignancy / bleeding / coeliac
What are your differentials to look for in blood
Caclium Thyroid Urine dipstick FBC qFIT COeliac serology
What does pT3 mean in lab report
Pathology reports umour as stage T3
What does yP
After neoajuvant treatment
ANATOMY
SMA 2nd part of duodenum to 2/3 tranverse
IMA supplies the rest to superior rectum
Marginal artery supplies whole gut (supplies colon in L colonic resection as on L side)
SMA = L1
IMA = L3
What are the flexures of the colon
Hepatic - SMA
Splenic - IMA
What are the nodes of the colon
Same as arterial supply
Level of resection determined by nodes invollved as must remove all nodes supplying tumour
Can’t see node so look at arteries
What is difference between end stoma or loop
End = irreversible
- One lumen
Loop is to defunction to protect distal anastomoses
- Two lumen
What side is more likely to need temp stoma
More distal = more likely to need stoma
R side usually okay
L side as presents obstructed
Rectal = most common
What side tend to do worse
R side as SMA blood supply
If person presents obstructed / perforation what do you do
Anastomosis is difficult
Stent = option
Loop stoma then fix at later date - ileostomy
When can you anastomose even in emergency
Ileo-caecal
What is HArtman’s procedure for
Emergency procedure for ruptured sigmoid / L colon with end colostomy formed in LIF
Proctosigmoidectomy with end colostomy
Rectum stump closed
Can go back after and reconnect
NO ANASTOMOSIS so no risk of anastomotic leak
When do you do left hemicolectomy
Splenic
Descending
Colon-colon
When do you do R hemicolectomy
Caecal
Transverse
Ileo-colon
What tumour marker for disease progression
CEA
Not useful for screening
When do you do urgent referral within 2 weeks
> 40 weight loss and abdominal pain
50 bleed
60 anaemia or change in bowel
+ve QFIT
When should you consider referral
Mass
<50 PR bleed +- abdominal pain / change in bowel / weight loss / anaemia
do QFIT if don’t meet
- e.g. abdo pain and weight loss - no bleed
What is used post op for analgesia and why
Epidural as reduced time for normal gut transit to return
How do you check anastomoses has worked
Gastrograffin enema
How does anastomotic leak present
Usually day 4-5 Septic peritonitis depending on size Faecal / other material in drain bag Pain Guarding No bowel movement Hypotension Tachycardia Fever
How do you Dx
Gastrograffin
CT
How do you Rx
Surgery
What do you do if wound breaks down
Surgery
Emergency if deep and bowel showing
Can pack if superficial
What are early complications of stoma
Haemorrhage Stoma ishcaemia High output which can lead to hypokalaemia / dehydration / acidosis due to loss of bicarb - SOB etc do ABG if suspect Malabsorption as lose bowel length Obstruction 2 to adhesion Stoma retractions Infections Infarction = necrotic
What d you consider in high output
Loperamide + codeine to thicken
What are delayed complications
Skin irritation / dermatitis Prolapse Obstruction Granuloma Intussception Stenosis Hernia - increase in size when cough Fistula
How do you follow up after curative resection
CT CAP - 1,2,3 years
Colonsocpy at 1 and 5 years
CEA 6 monthly for 3 years
What can anorectal cancer be
Key anatomy
Squamous = 80%
Adenocarcinoma if purely rectal
Split into 3rds
Top 3rd completed covered by peritoneum
Middle third covered anteriorly by peritoneum
Both supplied by superior rectal (branch of IMA)
Lower 3rd has no periotneal covering
Supplied by middle and inferior rectal artery (branch of common iliac)
Rectal more common spread to lung as inferior rectal vein goes direct to IVC not portal HTN
How does it present
Similar to haemorrhoids / fissure Bleeding - bright red (compared to dark red in L side) Itch Lumps Obstruction Feeling of incomplete evacuation - due to tumour stretching rectum Mucous discharge = characteristic Loss of continence Morning diarrhoea - Constipated due to tumour but in the morning wake up and blood and mucous fall out
How do you investigate / prepare for pre-op
Bloods Rectal exam + Procotscopy / sigmoidoscopy for initial Sx Colonoscopy / CTC to look for further cancer Biopsy Staging- CT CAP Local staging - MRI / EUS Bowel prep Stoma marking
What do you test for if Dx
HIV
Where does anorectal cancer spread too
Proximal / above dentate = to pelvic
Anal margin = inguinal
More distant is uncommon
What do you do if present obstructed
Defuction stoma until can stage cancer
Don’t resect as won’t be able to anastomose
What are RF
HPV
SMoking
Weakened immune system - HIV
How do you treat SCC prior to surgery
RT as extraperitoneal and high risk of recurrence (can’t have RT in colon)
80% = squamous
How do you treat adenocarcinoma (rare) prior to surgery
Chemo + RT
RT only in rectal
Laparoscopic resection
Surgical options
Anterior perineal if If sphincter invovled Very low 2cm clearance margin needed Leaves patient with permanent colostomy
Anterior resection if upper / middle rectum (part of bowel and rectum)
- Most surgeons defunction below peritoneal reflection as high risk of anastomotic leak below
e. g. loop ileostomy (temp stoma to allow time to heal) - Closed in 6-8 weeks if Gastrograffin enema shows no leak or stricture)
What are complications
Recto-vaginal fistula
Damage to ureter / spleen as L colon fully mobilised during operation
Anastomotic leak
Abscess
Sexual / urinary dysnfciton = later complication
What is the peritoneal reflection
Upper third of rectum covered by peritoneum
Lower 2/3 aren’t
Post op analgesia
Epidural useful as decreased time to normal bowel function
What should be done before reverse of loop stoma to check anastomosis has worked
Gastrograffin
What is the least risky stoma to create which can be easily reversed
Loop ileostomy
Could do colonostomy but large bowel takes longer to heal and higher risk of anastomotic leak
What is important when thinking of complications
Anatomy of where structures are
If R colon what are important relations
DUODENUM = most important
R kidney
R urea
If transverse colon
Stomach
Pancreas
If L colon
Spleen = most important
L kidney
L ureter
If duodenum was damaged how may the present
Bile in drain causing leak into colon
If spleen was damaged
Cause bleeding
Patient would be tachycardia then shock
If ureter damaged
May get urine in drain (need to analyse fluid)
May have AKI
Appendicitis and colon cancer
Tumour can obstruct appendix
Tumour can perforate and produce an appendicitis picture with raised inflammatory
What should you do if >40 + appendicitis
CT scan
Prior to elective op what is needed as FY1
Bloods
Colonic visualisation
Staging
Bowel prep
What bloods
FBC
U+E
LFT
Probs more e.g. X-match etc
What do you do if low Hb
If 70-100 ask senior
If <70 then transfuse
Why U+E / LFT
Liver mets
Tumour can obstruct ureter
What colonic visualisation is required
Colonoscopy
CT colonograph
What is used to stage
CT CAP
Why is bowel prep required
Increase likelihood of successful anastomosis
If large-large and full of faces won’t be successful
If small - large ie. in R hemicolectomy then will be fine as small bowel just liquid
What do you do
ASK NURSE for consultant preference as all different
What else can be used to view the colon
Proctoscopy
Flex sigmoidoscopy
What does colonoscopy require
Bowel prep
Sedation
Not suitable if CVS disease
Small risk of perforation / bleed
When do you use
If suspect colon as must see whole colon due to having multiple tumours
PR bleed
Anaemia
Change in bowel
When would you do CT colonograoh
If elderly / frail
Has high radiation dose
When do you do proctoscopy
To view ANAL canal for haemorrhoids
When would you do flex sigmoid
If young patient with PR bleed
Can see up to splenic flexure (70% malignancy)
Also if PR bleed must have come from below
What does consent for an op involve
Why needed Whats involved Any alternative Possible complications Risk of stoma
What post op care is needed
Pain relief DVT prophylaxis IV fluid Monitor urine output Physio Possible oral intake
What are complications of heme-colectomy
General surgery INtra-abdo abscess Anastomotic leak Damage to structure - Duodenum - Spleen - Ureter Haemorrhage shock
When is emergency surgery to colon carried out
Obstruction
Complicated diverticular disease
Perforation
If R colon what can you do
Ileo-colic anastomosis if resectable (less risk as more proximal)
Ileostomy if non-resectable
If L colon what can you’d o
Proximal stoma with ileo-colic anastomosis
Hartmann’s
If want to avoid stoma what can you do
Resection of tumour with primary anastomosis - high risk of leak
+- defunctioning stoma
When are colonic stents used
If unfit
If high volume metastatic disease
As bridge to surgery in LBO
What are complications
Perforation
Migration
Obstruction
Other indications stoma
IBD
AFP
Sepsis - intra-abdo
Haemorrhage
What do you do if someone has stoma
Full Hx Fluid balance Obs Bloods - FBC, U+E, CRP CT AP if comlplications
What is important post op
VTE prophylaxis as high risk
NUTRITION
What can you do for metastatic disease
Can remove
Before or after the primary
