colorectal cancer Flashcards
is colon or rectal cancer amenable to radiotherapy?
The mainstay of colorectal cancer management is surgical resection.
The major difference between colon and rectal cancer is the neoadjuvant stage (pre-operative therapy).
Rectal cancer, unlike colon cancer, is amenable to radiotherapy as it is an extraperitoneal structure.
chemotherapy can be used as neoadjuvant for colon cancer
what are the 2 pathways towards a colon cancer?
- The most common is the adenoma-carcinoma sequence whereby there is progression from an adenomatous polyp to adenocarcinoma due to mutations in APC, p53, and K-ras.
- (microsatellite instability) is due to defects in DNA repair genes (MLH-1 and MSH-2).
what are the hereditary conditions associated with colorectal cancer?
FAP, HNPCC, Peutz-Jeghers syndrome
what are the risk factors for colon cancer?
- Increasing age: peak age of 85-89 years old
- Smoking
- Obesity
- Red or processed meats
- Inflammatory bowel disease
- Hereditary conditions: FAP, HNPCC, Peutz-Jeghers syndrome
what is the difference in the presentation of right sided vs left sided tumours in colorectal cancer?
right-sided tumours are often asymptomatic, with the majority of patients presenting with incidental iron-deficiency anaemia.
In contrast, left-sided tumours are particularly associated with a change in bowel habit and have higher rates of rectal bleeding and tenesmus .
which investigations would be done when suspecting a colon cancer?
FBC- microcytic anaemia
- UandE- deranged in advanced pelvic diseases
- LFT deranged in metastatic disease
- colonoscopy and biopsy
- CT abdo and pelvis (CAP) for staging
- CEA antigen to monitor progress of disease
what is used to stage tumours?
- TNM staging or Dukes criteria
dukes: A- limited to submucosa B1- muscular layer b2- serosal layer- transmural C- local lymph node involvement D- distant metastasis
what is initial treatment for colon cancer?
Iron replacement: should be started immediately for patients with iron deficiency anaemia whilst awaiting for further investigations
what are the options for elective management of colon cancer?
Neoadjuvant therapy: for locally advanced or metastatic tumours
Colon cancer: chemotherapy
Rectal cancer: radiotherapy (T3 and above) or chemoradiotherapy
Surgical resection: for all stages of colorectal cancer
If the cancer is metastatic, the primary tumour, along with metastases to the liver and lung, can still be resected as this has been shown to improve survival
Adjuvant chemotherapy: for locally advanced or metastatic tumours
Oxyplatin, fluorouracil, and folinic acid is an example of one regime
what are the options for emergency treatment of a colon/ rectal cancer?
emergency-> large bowel obstruction/ perforation
colon cancer:
Resection and anastomosis:
Hartmann’s procedure: is usually performed for obstructing sigmoid tumours, where anastomosis would be risky
rectal cancer:
- staging must be done before resection
- often abdominoperineal resection is preformed
which tumours have higher risks of anastomotic leak?
distal tumours have an increased risk of anastomotic leak
which patients need to be referred under the 2WW rule for colon cancer?
≥ 40 years old with unexplained weight loss and abdominal pain
≥ 50 years old with unexplained rectal bleeding
≥ 60 years old with iron-deficiency anaemia or changes in bowel habit or
Tests show occult blood in their faeces
when should you consider a 2WW for someone <50?
rectal bleeding AND any of the following unexplained features:
Abdominal pain
Change in bowel habit
Weight loss
Iron-deficiency anaemia
which patients should be offered FIT tests?
≥50 years old with changes in their bowel habit or iron-deficiency anaemia
≥60 years old with anaemia, even in the absence of iron deficiency
what is the bowel cancer screening programme which id available in the UK?
FIT Testing is offered every 2 years: to all men and women aged 60 to 74 years in England
screening can be requested every 2 years by patients over 74 years old
