Colorectal Cancer Flashcards
What are the components of the large bowel?
The caecum, ascending colon, transverse colon, descending colon, sigmoid colon and the rectum
What is colorectal cancer?
A tumour within the large intestine
- Abnormal or uncontrolled growth of cells lining the large intestine
- Benign polyps undergoing malignant change
What are the risk factors for colorectal cancer
Age (≥50yo)
Genetics
Presence of polyps
- Hyperplastic - non-cancerous
- Adenomatous - low/high grade dysplasia (not necessarily cancerous cells)
- Malignant - Contains cancer cells (Adenocarcinoma)
Lifestyle
- Low fibre
- Increased red processed meats
- Increased alcohol intake
- Smoking
- Obesity
- Sedentary lifestyle
What are some signs and symptoms?
Changes in bowel habits
- More common complaint in descending colon due to growth blocking firmer stools in left colon over right colon
Abdominal discomfort
Blood in stools and/or bleeding from rectum
Iron deficiency anaemia
Fatigue
Unintentional weight loss
Tenesmus
- Wanting to pass a bowel motion but there is no bowel motion, it’s just the cancer
Bowel screening positive faecal immunochemical tests (microscopic blood in stool)
What are some advanced symptoms
Abdominal distension (ascites)
Bowel obstruction
Vomiting
Unintentional significant weight loss
Hepatomegaly
What are some diagnostic tests?
Rectal examination and patient history
Sigmoidoscopy
Colonoscopy
- Viewing entire length of prepper colon
- +/- polyptectomy
- biopsy
Carcinoembryonic antigen
- Tumour marker
- 50% have increased CEA
- Not a stand-alone diagnostic test
- For surveillance and indication of response to treatment
CT/PET/MRI scans
What are the components of TNM staging of cancers?
T - Size of TUMOUR (T1, T2, T3, T4)
N - Lymph NODE involvement
- N0 = no nodes
- N1 = 1-3 nodes
- N2 = ≥4 nodes
M = METASTASES
- M0 = No metastases
- M1 = Metastases
- MX = Cannot be determined
What does tumour grade measure?
What are the different tumor grades?
The similarity of the cells to normal cells.
Well-differentiated (Low grade)
- Well-organised cells similar to original cells in the area
Moderately differentiated (intermediate grade)
- Somewhat different to the original cells
Poorly differentiated (high grade)
- Bearing little resemblance to original cells
Undifferentiated
- No resemblance to the original cells
What are some negative prognostic factors?
Presenting with obstruction
Perforation
Invasion of adjacent organs
High-grade or undifferentiated tumor grading
Heavy nodal involvement >4 nodes
Vascular invasion
Right-sided colon cancer
Where does colon cancer most commonly metastasise to and why?
Most commonly metastasises to the liver due to the hepatic portal vein
Is surgical resection for colorectal cancer done for curative or palliative intent?
Curative intent, complete removal of cancer, which may be given alongside chemotherapy
What is chemotherapy?
Cytotoxic drugs administered and targetted towards killing quickly dividing cells such as cancer cells
If chemotherapy is to be given in combination with surgery, what are the two time periods in relation to the surgery that it will be administered and why?
Neoadjuvant - Chemo prior to surgery to shrink the tumour for an easier resection (improved surgical outcome)
Adjuvant - Chemo post-surgery to eliminate any remaining microscopic cancer
What is radiotherapy?
Localised treatment using targeted radiation beams. It may be given alongside chemotherapy and before surgery
What are targeted therapies?
Non-funded therapies are typically given in combination with chemotherapy that target a specific gene in cancer cells, causing them to undergo programmed cell death (apoptosis)
