Blue Book: Tumour Markers

Question 1

What is sensitivity and specificity.

Answer 1

Sensitivity: ability to detect those with a certain disease.
Specificity: ability to accurately define those who are disease free.

Question 2

Are tumour markers useful for the following:
Screening
Diagnosis
Prognosis
Response
Relapse

Answer 2

Screening: No
Diagnosis: May be raised but also raised in benign conditions.
Prognosis: Some can be good and can influence management. Eg HCG and aFP in testicular teratoma.
Response: most useful feature.
Relapse: If patient had high levels of the marker during the disease (‘marker positive’) subsequent increases suggesr relapse. But not all will show changes in marker levels.

Question 3

What is CEA?

When is it raised?

Answer 3

cell surface antigen expressed in many normal tissues. It is elevated in a wide number of tumours but is useful in colorectal carcinoma.

The elevation is related to the clinical stage (4% in Dukes stage A, 65% with D).

Elevation is also common in people who smoke, inflammatory bowel disease, hepatitis, pancreatitis and gastritis.

Question 4

CA125:

What is it?
What is it used for a marker off?

Sensitivity/specificity

What other cancers is it elevated in?

Answer 4

antigen on the surface of ovarian cells, marker of ovarian cancer.

1% raised in normal women
6% raised with benign conditions (preg, endometriosis, PID
82% ovarian carcinoma

Pancreatic (59%), L:ung (32%), colorectal (21%), breast cancer (12%)- especially if disseminated.

Question 5

Alpha fetoprotein (aFP)

What is it?
If raised in adult life, what may this indicate?
High levels indicate what?

Answer 5

a glycoprotein produced in the 1st year of life by the normal yolk sac, liver and intestines. It is undetectable after the first years of life.

Hepatitis (moderate)
Hepatocellular carcinoma
Cancers containing yolk sac (teratoma)

High levels= poor prognosis

Question 6

Human chorionic gonadotrophin (HCG)
(2 subunits)

When is it raised (other than in pregnancy)

Answer 6

Gestational trophoblastic disease (hydatiform mole, choriocarcinoma)

B-subunit raised in non-seminomatous testicular cancers.

Question 7

Prostate specific antigen (PSA)

What is it?
When is it raised?
Is it specific/sensitive

Answer 7

Benign protein released by prostatic cells.

prostate cancers
benign hypertrophy of prostate (most of old men)
rectal examination
prostatitis 
UTI

Lacks specificity and sensitivity. Only used in monitoring response to hormonal and cytotoxic treatments.

Question 8

Immunoglobulins can be a measure of what?

Where can they be measure.

Give 2 examples.

Answer 8

paraproteinaemias
- myeloma and waldenstroms
they can be measured in the blood or as light chains in the urine eg bence-jones protein which occurs in 40-50% of myelomas.