Colorectal Cancer Flashcards
How common is colorectal cancer?
3rd most common cancer in the UK. Usually adenocarcinoma.
What are the risk factors for colorectal cancer?
Age – vast majority are over the age of 60
Polyps
Family History such as FAP or HNPCC
IBD (IC or Crohn’s)
Diet – low fibre and high red and processed meats
Alcohol and smoking
What is Lynch/HNPCC?
Lynch or HNPCC – autosomal dominant due to mutations in mismatch repair genes. Also influences endometrial, ovary, urinary, stomach, small bowel and hepatobiliary. Those with these have colonoscopic surveillance every 1-2 years between 25-75 and should be considered for prophylactic surgery.
What is FAP?
FAP (familial adenomatous polyposis) – mutations in the APC tumour suppressor gene causing multiple adenomas which undergo malignant transformation. Autosomal dominant with 100% gene penetrance by age 50. 100% risk of cancer so surveillance sigmoidoscopy from 15yrs (if nothing found then 5 yearly from then). Often get prophylactic surgery.
What is Peutz-jaghers syndrome?
Peutz-Jeghers Syndrome – autosomal dominant STK11mutations resulting in Hamartomatous polyps with significantly increased risk of GI and breast cancer. Surveillance in all with annual examination with pan intestinal endoscopy every 2-3 years. Have a classical pigmentation pattern.
What are the clinical features of left sided colorectal cancer?
Left sided Bleeding Mucus Altered bowel habit Tenesmus Abdominal pain Obstruction
Either side Abdominal mass Perforation Haemorrhage Fistula
What are the features of right sided colorectal cancer?
Right sided Weight loss Anaemia Abdominal pain Obstruction less likely
Either side Abdominal mass Perforation Haemorrhage Fistula
How should suspected colorectal cancer be investigated?
FBC (microcytic anaemia), LFTs, UE, Bone profile
Faecal Immunochemical test
Sigmoidoscopy or colonoscopy and biopsy for histological staging
Virtual CT – colonography
Liver MRI/US
DNA testing if strong family history
CEA – carcinoembryonic antigen to monitor disease progression or regression
Describe the criteria in TNM staging of colorectal cancer?
TNS Staging T1 = invading submucosa T2 = Invading muscularis mucosa T3 = Invading subserosa and beyond but not other organs T4 = Invasion of adjacent structure
Where does colorectal cancer metastasis to?
Spreads to Liver, lung and bone or other places in the bowel (transcoelomic)
What are the urgent referral criteria for colorectal cancer?
Positive Faecal Immunochemical test
>40yrs with abdominal pain and weight loss
>50yrs with unexplained rectal bleeding
>60yrs with iron deficient anaemia or change in bowel habit
If men are found to have Hb < 110 and women <100.
When should a referral be considered for colorectal cancer?
Rectal abdominal mass
Anal ulceration
<50yrs with rectal bleeding and lower GI symptoms or weight loss or anaemia
When is Faecal Immunochemical testing indicated?
> 50yrs with abdominal pain or weight loss
<60yrs with change in bowel habit or iron deficiency anaemia
60yrs with any anaemia
How is colorectal cancer managed?
Surgery – aim to cure. Anastomosis typically on first operation
Right hemicolectomy for caecal, ascending or proximal transverse colon
Left hemicolectomy for distal transverse or descending tumours
Sigmoid colectomy for sigmoid tumours
Anterior resection for low sigmoid or high rectal tumours
Abdominal-perineal resection for tumour low in the rectum with permanent colostomy and removal or rectum and anus.
Hartmann’s procedure if presenting with acute perforation
How should analgesics be given post operatively in colorectal cancer?
Analgesics post-operative should be given by epidural as it speeds return to normal bowel function.
