Colorectal Cancer Flashcards
What are the colorectal cancer screening recommendations for the average risk (general) population?
Individuals aged 50-74 should be screened with a FIT or gFOBT Q2 years OR a flexible sigmoidoscopy Q10 years.
RECOMMEND AGAINST screening colonoscopy.
What are the CRC screening recommendations for individuals at increased risk?
If 1 FDR with CRC or advanced adenoma - Screen with colonoscopy Q5-10 years starting at age 40-50 years or 10 years before the earliest age of a relative’s diagnosis (whatever is youngest).
If > FDR with CRC or advanced adenoma, screen with colonoscopy Q5 years starting at age 40 or 10 years before the earliest age of a relatives diagnosis, whichever comes first.
FIT q1-2 years can be considered an alternative screening test in individuals with 1 affected FDR.
Which individuals are considered high risk for CRC and need to be screened more frequently than the average or increased risk populations?
- Familial Adenomatous Poyposis
- Lynch Syndrome (HNPCC)
- IBD (Crohn’s or UC)
What is Lynch Syndrome?
- Most common inherited CRC susceptibility syndrome, responsible for ~ 8% of incident CRC diagnosed < 50 years old.
- Germline mutation in 1 of the DNA mismatch repair genes.
What is the “3-2-1”rule of Lynch Syndrome?
Summarizes part of the Amsterdam II Criteria for the diagnosis of Lynch Syndrome:
3 - relatives or more with any Lynch syndrome associated cancer
2 - at least 2 generations affected
1 - one diagnosis < 50 years old
Other criteria include exclusion of FAP and that one of the 3 relatives has to be a FDR of the other two.
What are the malignancies associated with Lynch Syndrome?
- CRC (Most common)
- Endometrial (2nd most common)
- Small Bowel
- Ureter
- Renal Pelvis
What are the CRC screening recommendations in patients with Lynch Syndrome?
Start screening at age 20 or 10 years prior to the earliest age of a relatives diagnosis, with colonoscopy every 1 to 2 years.
Need to send these patients for genetic counselling as well.
What are the CRC screening guidelines for FAP?
Start screening at age 10-12 with a sigmoidoscopy every year.
What are the CRC screening recommendations for patients with IBD?
- Hx of Pan-colitis - Colonoscopy Q1-3 years, starting 8 years after Dx.
- Hx L-side colitis - Colonoscopy Q1-3 years, starting 12-15 years after Dx.
What is the mutation in familial adenomatous polyposis?
Inactivation of the APC tumour suppressor gene (both alleles).
What is the heritability pattern of FAP?
Autosomal dominant in inheritance with nearly complete penetrant each of colonic polyps but variable extracolonic manifestations.
How is colorectal cancer worked-up when identified by screening?
- Full colonoscopy to terminal ileum.
- CT Chest/Abdo/Pelvis
- Carcinoembyronic Antigen (CEA)
What are the stages of colorectal cancer?
Stage I: Invades into muscle wall.
Stage II: Invades through muscle wall.
Stage III: Lymph node involvement
Stage IV: Distant metastases
How are Stage I-III CRC treated?
Stage I: Surgery
Stage II: Surgery +/- adjuvant chemotherapy if perforated or obstructed.
Stage III: Surgery + adjuvant chemotherapy
How is Stage IV CRC treated?
Oligometastatic (isolated liver or lung lesions) - Metastectomy + chemotherapy.
Non-Operable - Palliative chemotherapy.
