- Most bowel cancers are diagnosed in symptoamtic patients
- 2nd most common cause of cancer death
- Risk Factors
- Age >45 years (accounts for 90% of Colon Cancer)Inflammatory Bowel Disease
- Ulcerative Colitis – Risk increases with duration since diagnosis (2% at 10 years of disease, 18% at 30 years of disease)Crohns Disease – Lifetime risk of Colorectal Cancer: 4-5%
- Family History (non-syndrome related)
- Higher risk Family History Criteria (RR 3-4x)
- One first degree relative with Colorectal Cancer or advanced adenoma before age 60 years
- Two first degree relatives with Colorectal Cancer or advanced adenoma at any age
- Moderate risk Family History Criteria (RR 2-3x)
- One first degree relative with Colorectal Cancer or advanced adenoma age 60 years or older
- Two second degree relatives with Colorectal Cancer or advanced adenoma at any age
- Higher risk Family History Criteria (RR 3-4x)
- Hereditary Syndromes
- Familial Adenomatous Polyposis (>100 synchronous advanced adenomas)
- Diagnosed on average by age 39 years, and 87% develop Colon Cancer by age 45 years old
- Hereditary non-polyposis Colon Cancer (Lynch Syndrome)
- Diagnosed on average by age 45 years, and 75-80% lifetime Colon Cancer risk
- Autosomal Dominant condition
- Most common cause of inherited Colorectal Cancer
- Peutz-Jeghers Syndrome (Hamartomatous Polyposis)
- Symptomatic polyps by age 10 to 30 years
- Sessile Serrated Adenomatous Polyposis
- Diagnosed on average by age 62 years, and 25-70% have Colon Cancer at time of diagnosis
- Familial Adenomatous Polyposis (>100 synchronous advanced adenomas)
- Lifestyle related risks
- Tobacco Abuse
- Current smokers have a 2 fold higher Relative Risk of high-risk adenomas or Colorectal Cancer
- Obesity
- BMI 35-40 associated with Colorectal Cancer mortality Relative Risk 1.8 in men, 1.4 in women
- Bariatric Surgery reduced Colorectal Cancer rtisk by 27%
- Tobacco Abuse
- Dietary Risk Factors
- Dairy products have a minimal impact on Colorectal Cancer risk
- Red Meat
- Foods with possible higher risk: Salt-cured, pickled, smoked, barbeque
- Red meat consumption does increase Colorectal Cancer risk
- Age >45 years (accounts for 90% of Colon Cancer)Inflammatory Bowel Disease
- Spread
- Lymphatics – epigastric and para-aortic nodes
- Direct- peritoneum
- Blood – portal ciruclation
- Symptoms may depend on location
- Right – anaemia, dyspepsia, mass
- Left – pain, obstruction, altered bowel habit
- Sigmoid – obstruction, altered bowel habit, rctal bleeding
- Distal bowel/rectal – mass, rectal bleeding, tenesmus
- History
- Often common , non specific symptoms with many causes- be suspicious if there is a combination of > 1 symptom or aged > 50
- Altered bowel habit
- Frequency, consistency, calibre(narrowing)
- Often increased frequency/loose stools if left sided
- If change in bowel habit persists > 6 weeks – consider suspicious for malignancy/other pathology
- Rectal bleeding
- More commonly intermixed
- Abdominal pain
- Anal pain and tenesmus
- Constitutional symptoms – weight loss, night sweats, fevers
- Symptoms of anaemia
- Fatigue, dizziness, SOB, exercise intolerance, palpitations, apthous ulcers, angular chelitis, restless legs
- Explore family history
- Any other GI disorders
- Examination
- Vitals, height, weight, BMI
- Signs of anaemia – pallor, tachycardia, heart murmur
- Palpate abdo – focal tenderness, masses, organomegaly
- Regional lymphadenopathy
- Perianal region – haemorrhoids or fissures to differentiate
- DRE – exclude rectal mass
- Investigations
- Baseline bloods, inc iron studies
- If iron deficient – needs scopes
- If abdominal pain/mass – consider CT
- If there are red flags or > 1 colorectal symptom – refer for surgery or gastro assessment
- If identify benign pathology (e.g. Hemorrhoids) – manage accordingly and review at 6-8 weeks. If persistent or worsening symptoms refer
- CEA is not useful for diagnosis – may be for monitoring response to treatment
- Management
- Early surgical excision
- Chemotherapy depending on prognosis
- Follow up generally includes
- CEA antigen
- Colonscopy
- Abdominal imaing
- Avoid risks
- Smoking
- Low EtOH
- Healthy BMI
- Aspirin 100mg for 2.5 years between 50 – 50 years
- Diet low in processed/red meat
- High fibre
Bowel Cancer Screening
- CRC has pre cancerous stage as a polyp – 3 different pathways
- Adenoma- carcinoma sequence (APC gene)
- Serrated apthway (KRAS and BRAF)
- Familial pathways – Lynch, familial adenomatous polyposis
- Screening aims to identify people harbouring a polup, and remove polyp or early cancer
- FOBT
- Two forms – guiac and immunochemical
- Immunochemical is used routinely – unlike guiac which is effected by diet, medications, red meat, vitamin C, anti-inflammatories
- If macroscopic loss or symptomatic- refer for colonoscopy – do not do FOBT
- Population screening
- FOBT
- Commence 50 up to 74
- Every 2 years
- Consider aspirin for prevention
- all patients age 50- 70 years for prevention
- Low dose 100-300mg
- Take for 2.5 years at any point during this time
- Reduces occurrence of CRC by 24%
- If there is a family history –
- Use number and age of relatives diagnosed to risk stratify – then proceed with recommended screening
- Note – the relatives need to be on the same side of the family to represent increased risk
- If a familial polyp syndrome is diagnosed or suspected
- – genetic/ specialist management and follow up
- likely more frequently than the Category 3/ high risk guidelines
| Risk stratification based on family history – Current screening guidelines based on family history | ||
| Category 1 (relative risk x 1–2) | Category 2 (relative risk x 3–6) | Category 3 (relative risk x 7–10) |
| Asymptomatic people who have: no personal history of bowel cancer, colorectal adenomas, inflammatory bowel disease or family history of colorectal cancer (CRC) OR one first-degree relative with CRC diagnosed at 55 years or older OR one first-degree and one second-degree relative with CRC diagnosed at 55 years or older | Asymptomatic people who have: one first-degree relative with CRC diagnosed before age 55 years OR two first-degree relatives with CRC diagnosed at any age OR one first-degree relative and at least two second-degree relatives diagnosed with CRC at any age. | Asymptomatic people who have: at least three first-degree or second-degree relatives with CRC, with at least one diagnosed before age 55 years OR at least three first-degree relatives with CRC diagnosed at any age. |
| Immunochemical faecal occult blood test (iFOBT) should be considered every two years from age 45 years, given the risk of colorectal cancer at this age is approximately equivalent to the population risk at age 50 years For patients aged 50–70 years, low-dose aspirin (100 mg) daily should be considered | iFOBT should be performed every two years from age 40 to 50 years Colonoscopy should be performed every five years from age 50 to 74 years. Computed tomography (CT) colonography can be offered if colonoscopy is contraindicated Low-dose (100 mg) aspirin daily should be considered As a result of the possibility of Lynch syndrome, a complete family history should be taken and updated regularly, and the accuracy of the cancer diagnoses and polyp pathology should be checked carefully Genetic testing is not appropriate at present for people with category 2 risk | iFOBT should be performed every two years from age 35 to 45 yearsFive-yearly colonoscopy from age 45 to 74 years. CT colonography can be offered if colonoscopy is contraindicated Low-dose (100 mg) aspirin daily should be considered Referral to a genetic centre for hereditary cancer syndromes should be considered |
