Tumour Markers

Question 1

READ:

Sensitivity is the percentage of patients with a particular disease who have elevated marker levels and are therefore true positives

Specificity is the percentage of patients without disease who have normal marker levels and are therefore true negatives

Positive predictive value is the percentage of positive results (i.e. elevated marker levels) which are true positives

False-positive rate is the percentage of patients without disease who have an elevated marker level

False-negative rate is the percentage of patients with disease who have a normal marker level

Answer 1

READ:

Sensitivity is the percentage of patients with a particular disease who have elevated marker levels and are therefore true positives

Specificity is the percentage of patients without disease who have normal marker levels and are therefore true negatives

Positive predictive value is the percentage of positive results (i.e. elevated marker levels) which are true positives

False-positive rate is the percentage of patients without disease who have an elevated marker level

False-negative rate is the percentage of patients with disease who have a normal marker level

Question 2

Marker for:

• Testicular cancer
• Liver Cancer
• Germ cell tumours
• Gastric and pancreatic cancer
• GI malignancy
• Widespread mets
• Ovarian cancer
• Myeloma

Answer 2

Human chorionic gonadotrophin (hCG)

Alpha Fetoprotein

PLAP - placental alkaline phosphatase

CA19-9 - Found on the epithelium
- excreted via bile so any cholestasis leads to rise

CEA - carcinoembryonic antigen

Again, CEA - used to monitor response to Rx

CA125 - used for monitoring response and detection of relapse

Monoclonal paraproteins

Question 3

CA 15-3 - used in gynae cancers especially breast - use?

Answer 3

A rising CA 15-3 level during follow-up can detect relapse 2-9 months before clinical signs or symptoms develop

Question 4

Pelvic mass - risk of malignancy (RMI):

What is involved?

Answer 4

USS
Menopausal status
+ CA 125 levels

Question 5

SCC-associated antigen - used for monitoring Rx

Answer 5

SCC-associated antigen - used for monitoring Rx

Question 6

PSA - what is it?

Answer 6

Protease produced by prostate epithelium

Question 7

LDH - lactate dehydrogenase:

What does it measure?

Use?

Answer 7

Measures tumour bulk

Indicates necrosis as anything causing cell death and apoptosis causes the release of LDH

Non-specific but may identify patients at risk of tumour lysis syndrome

Question 8

How often should a marker be checked after completing treatment?

Answer 8

Every 3 months - 2 yrs
Every 6 months - 3 years

No monitoring after 5 years - no longer in remission