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.
How is colorectal cancer managed if the cancer has spread to one liver lobe?
Surgery with liver resection if only one in one lobe of liver
How should colorectal cancer be treated palliatively?
Endoscopic stenting for palliation
Radiotherapy in palliation and sometimes neo-adjuvant or adjuvant for rectal tumours
Chemotherapy – adjuvant for stage 3 and above or for palliation
What biological therapy can be used in colorectal cancer?
Biologicals – anti VEGF Bevacizumab with combination therapy
What screening occurs for colorectal cancer?
One off flexible sigmoidoscopy in someone’s 55th year
Between 60 and 74 Faecal immunological test every 2 years followed by colonoscopy if positive
What is anal cancer?
Relatively rare malignancy lying exclusively in the anal canal (between the anorectal junction and the anal margin). 80% of anal cancers are squamous carcinomas, can also get melanomas, lymphomas, and adenocarcinomas.
What are the risk factors for anal cancer?
HPV infection (16 and 18 subtypes)
Female (1:2)
Older age
Anal intercourse and high number of lifetime sexual partners
Men who have sex with men
HIV including those taking immunosuppressive medication for HIV
Women with a history of cervical cancer or CIN
Any immunosuppressive drug use
Smoking
How does anal cancer usually present?
Perianal pain Perianal bleeding Faecal incontinence Tenesmus Neglected tumour in a female may present with rectovaginal fistula
How should anal cancer be investigated?
DRE Anoscopic examination with biopsy Palpitation of inguinal lymph nodes CT or MRI Endo-anal USS PET STI screen including HIV and HPV
What is MYH syndrome?
MYH (Mut Y human homologue) – autosomal recessive, 100% cancer risk by age 60 but much more common to be right sided. If identified, then resection and ileoanal pouch reconstruction recommended.
What is Cowden’s disease?
Cowden disease – autosomal dominant mutation of PTEN gene. Causes macrocephaly and 89% risk of cancer at any site (16% colorectal risk). Receive targeted individualised screening.
What surgery is done for anal tumours
Upper rectum Anterior resection (TME) Colo-rectal
Low rectum Anterior resection (Low TME) Colo-rectal
(+/- Defunctioning stoma)
Anal verge Abdomino-perineal excision of rectum None
