Colorectal cancer Flashcards
what is the most common type of colorectal cancer
adenocarcinoma
Rarer types include lymphoma (~1%), carcinoid (<1%), and sarcoma (<1%).
what is the typical progression to colorectal cancer
adenoma-carcinoma sequence
progression of normal mucosa to colonic adenoma (colorectal ‘polyps’) to invasive adenocarcinoma
Adenomas may be present for 10 years or more before becoming malignant; progression to adenocarcinoma occurs in approximately 10% of adenomas.
who is offered screening for colorectal cancer
Screening is offered every 2 years to men and women aged 60-75 years. For most of the UK, a faecal immunochemistry test (FIT) is used. If positive follow up is generally with specialist and offered a colonoscopy
who should be referred for urgent investigations of suspected bowel cancer
≥40yrs with unexplained weight loss and abdominal pain
≥50yrs with unexplained rectal bleeding
≥60yrs with iron‑deficiency anaemia or change in bowel habit
anyone with a Positive occult blood screening test
risk factors for colorectal cancer
Increasing age
M>F
high fat low fibre diet
FHx
high alcohol consumption, smoking
IBD (especially UC)
Genetic predisposition: HNPCC, ANP/FAP
presentation of right sided colon cancer
abdominal pain, iron-deficiency anaemia, palpable mass in right iliac fossa
often present late, as stools are less formed and there is a wider lumen here so they are able to pass through until there is a larger tumour causing occlusion.
presentation of left sided colon cancer
rectal bleeding, change in bowel habit, tenesmus, palpable mass in left iliac fossa or on PR exam
presents sooner due to stools being more formed, and narrower lumen so more likely to experience symptoms of obstruction
what is a tumour marker for colorectal cancer
Carcinoembryonic Antigen
due to poor sensitivity and specificity its not diagnostic
can be used for monitoring disease progression and should be conducted both pre- and post-treatment, screening for recurrence.
An elevated baseline CEA is associated with worse prognosis
when would you use MRI rectum in colorectal cancer
Rectal cancer only
to assess the depth of invasion and potential need for preoperative chemotherapy
what is the general curative option for colorectal cancer
regional colectomy, to ensure the removal of the primary tumour with adequate margins and lymphatic drainage, followed either by primary anastomosis or formation of a stoma
Chemotherapy and radiotherapy have an important role as neoadjuvant and adjuvant* treatments, alongside their role in palliation.
when is radiotherapy most appropriate in colorectal cancer
Radiotherapy can be used in rectal cancer (it is rarely given in colon cancer due to the risk of damage to the small bowel), most often as neoadjuvant treatment.
what surgical options are there for patients with low rectal cancer
(<5cm): anterior peritoneal resection
what surgical options are there for patients with high rectal cancer
(>5cm from anal verge): anterior resection +/- defunctioning loop ileostomy
what surgical options are there for patients with caecal cancer
right hemicolectomy +/- defunctioning loop ileostomy
