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.
What is the tumour marker for choriocarcinoma (malignant growth of chorionic villi developing from malignant hydatiform mole)?
Beta-HCG - an almost ideal marker; very sensitive i.e. the smallest rise may indicate underlying tumour
What markers are a/w testicular teratomas?
AFP and HCG
How do you diagnose and monitor phaeochromocytomas?
24 hour urinary metanephrines. These must be brought quickly to the lab for acidification.
How do you screen for medullary cell carcinoma (MTC)?
Blood calcitonin, also part of a pentagastrin DFT screening test. MEN2A syndrome.
What are examples of MEN1 cancers?
Pituitary adenoma
Parathyroid hyperplasia
Pancreatic tumours
What causes a rise in PSA?
Limited sensitivity and specificity. Prostate cancer, BPH, age can result in raised levels. DRE, prostatitis, UTI can transient raise levels.
What are examples of MEN2A cancers?
Parathyroid hyperplasia
Medullary thyroid carcinoma
Phaeochromocytoma
What serum markers do you check for bone mets?
Alkaline phosphatase (ALP) - this may be raised also in cholestatic liver disease, Paget’s, osteomalacia
What tumour marker is used in diagnosis and monitoring of ovarian cancer?
CA125 - this is also raised in benign conditions such as endometriosis
Concentration does not correlate to prognosis; and serial measurements used to monitor post resection and chemo
What conditions is the serum marker CA 19-9 associated with?
Pancreatic adenocarcinoma
Colorectal/ gastric carcinoma
PSC (rapid rise observed)
When would CA 19-9 levels appear low in patients with pancreatic adenocarcinoma?
Patients with blood types Lewis a and b, who do not produce CA19-9 and this cannot be used to monitor disease
What cancers are a/w PtHrP secretion?
Squamous cell lung cancer and renal adenocarcinoma. This leads to hypercalcaemia.
What marker is used to diagnose neuroblastomas?
Vanillylmandelic acid (VMA) and homovanillic acid (HVA)
