Oncology Flashcards
What are genetic associations for colorectal cancer?
K-ras, C-myc oncogenes and APC TSG
What tumour marker is associated with colorectal cancer?
Carcinoembryonic antigen (CEA) test
What imaging modality is used for staging i.e. to screen for mets? e.g. colorectal cancer
CT CAP
What are the most common sites for mets in colorectal cancer?
Liver, lung, peritoneum
When is radiotherapy indicated in treatment of bowel cancer?
The small bowel and colon are mobile and difficult to target with radiotherapy, constantly in peristalsis. Radiotherapy is only used in advanced rectal caner.
What classification system is used to classify colorectal cancers?
Dukes classification. They are divided into limited to the bowel wall (Dukes A), extended through the bowel tissue (Dukes B), with metastases to regional lymph nodes (Dukes C) and widespread metastases (Dukes D).
When do you consider chemotherapy in colon cancer?
For Dukes B and C tumours.
An autosomal dominant condition resulting from mutation in the tumour suppressor APC gene Ch5 which causes colonic polyps.
Familial adematous polyposis (FAP).
How do you manage FAP?
Screening from 14yo.
If >100 polyps, may require prophylactic colectomy.
An autosomal dominant condition resulting from mutations in MSH2, MSH6, MLH1, PMS2 genes, leading to defective mismatch repair. This leads to increased risk of GI and gynaecological malignancies.
Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome
Perianal pain, bleeding, palpable lump - what is the gold standard investigation?
Perianal malignancy; MRI with biopsy
What do high levels of AFP indicate?
This is non-specific - possibly hepatocellular carcinoma, or testicular teratoma (prognostic value, for staging/ monitoring) - rapid fall post-orchidectomy implies disease localised to testis.
May also be high in liver cirrhosis, pregnancy.
What do high levels of CEA indicate?
This is non-specific - present in 60% of patients with colorectal cancer, and 80-100% for patients with advanced disease with hepatic mets
Also present in liver disease, pancreatitis, IBD, heavy smokers
What is the role of CEA in screening for colorectal cancer?
It is not a sufficiently specific or sensitive marker/ or correlate with tumour bulk - so it is not routinely used
What is the role of serum or urinary paraproteins in diagnosis of myeloma?
They are used in detection of myeloma, and correlates well with tumour bulk. They are a good indicator of efficacy of treatment.