A 64-year-old man had a radical prostatectomy for prostate cancer 3 years ago. His PSA results on the same ultrasensitive assay (limit of quantitation 0.01 µg/L) are below 0.01 µg/L at 3 months after surgery, then, at 6-monthly intervals, 0.03, 0.06, 0.12, 0.24 and 0.29 µg/L. He has no symptoms. His urology team defines biochemical recurrence as a PSA of 0.2 µg/L (ng/mL) or more, confirmed on a second sample. A clinician asks whether the values can be ignored because all are far below 4.0 µg/L. What is the best interpretation?

Confirmed biochemical recurrence

Normal, as all values are below 4.0 µg/L

PSA from regrowing benign prostate

Assay noise near the detection limit

A man on surveillance for prostate cancer has had PSA results of 4.1, 4.3 and 4.2 µg/L (ng/mL) over 18 months on one assay. The laboratory then changes to another manufacturer's PSA assay, and his next result is 5.0 µg/L. What is the best response?

Allow for method bias and set a new baseline on the new assay

Reject the new assay as miscalibrated

Report that the rise proves the cancer has progressed

Convert the result with the old assay's reference range

A 27-year-old man has a testicular mass. Before orchiectomy: AFP 640 µg/L (reference < 10), hCG 85 IU/L (reference < 2), LD mildly raised; liver tests normal. The pathology report describes pure seminoma. Which conclusion do the markers best support?

A nonseminomatous component is likely present

These markers are typical of pure seminoma

The AFP was produced by the seminoma cells

The raised hCG proves a choriocarcinoma

In colorectal cancer care, serial serum CEA results add the most value when they are used for:

Detecting recurrence after colorectal cancer surgery

Screening adults at average risk for colorectal cancer

Monitoring ovarian cancer during chemotherapy

Confirming the diagnosis of colorectal cancer

A 66-year-old man has taken finasteride for benign prostatic enlargement for 2 years. His PSA is 2.1 µg/L (2.1 ng/mL). How should this result be interpreted?

It is about half the value expected without the drug

It is about double the value expected without the drug

It cannot be interpreted until the drug is stopped

It is unaffected, because finasteride does not alter PSA

Tumor markers

9 DOH Abu Dhabi (HAAD) lab licensing practice questions on Tumor markers, part of Clinical Chemistry. The first 9 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 64-year-old man had a radical prostatectomy for prostate cancer 3 years ago. His PSA results on the same ultrasensitive assay (limit of quantitation 0.01 µg/L) are below 0.01 µg/L at 3 months after surgery, then, at 6-monthly intervals, 0.03, 0.06, 0.12, 0.24 and 0.29 µg/L. He has no symptoms. His urology team defines biochemical recurrence as a PSA of 0.2 µg/L (ng/mL) or more, confirmed on a second sample. A clinician asks whether the values can be ignored because all are far below 4.0 µg/L. What is the best interpretation?
1. AConfirmed biochemical recurrence
2. BNormal, as all values are below 4.0 µg/L
3. CPSA from regrowing benign prostate
4. DAssay noise near the detection limit
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Answer: A · Confirmed biochemical recurrence
After radical prostatectomy the source of PSA has been removed, so PSA should stay undetectable and age-related cut-offs such as 4.0 µg/L do not apply. A steady rise from below 0.01 to 0.24 and then 0.29 µg/L on the same assay is far above its limit of quantitation and is not random noise. Two consecutive values of 0.2 µg/L or more meet the team's definition of biochemical recurrence. The PSA doubled about every 6 months, and this doubling time helps the clinician judge how aggressive the recurrence is. A change of PSA method during follow-up should be avoided or clearly flagged, because results are not interchangeable between assays.
- B: The 4.0 µg/L cut-off applies to men with a prostate; after prostatectomy PSA should be undetectable.
- C: Residual benign tissue gives a low, stable PSA, not one that doubles every 6 months.
- D: The values rise steadily and are far above the 0.01 µg/L limit of quantitation, so they are not noise.
Question 2 · Medium
A man on surveillance for prostate cancer has had PSA results of 4.1, 4.3 and 4.2 µg/L (ng/mL) over 18 months on one assay. The laboratory then changes to another manufacturer's PSA assay, and his next result is 5.0 µg/L. What is the best response?
1. AReject the new assay as miscalibrated
2. BReport that the rise proves the cancer has progressed
3. CConvert the result with the old assay's reference range
4. DAllow for method bias and set a new baseline on the new assay
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Answer: D · Allow for method bias and set a new baseline on the new assay
PSA assays from different manufacturers use different antibodies and calibrators, and they can give results that differ by 10 to 20 percent or more on the same sample. A method change can therefore look like a rise or fall in a patient's trend. Laboratories should tell clinicians when a tumor marker method changes, and patients being monitored should have a new baseline on the new method, ideally by testing a sample on both. Tumor marker trends are reliable only when one method is used throughout.
- A: Between-method differences are expected and do not mean the new assay is miscalibrated.
- B: A rise this size across a method change cannot be taken as progression without a new baseline.
- C: A reference range cannot convert a result from one method to another.
Question 3 · Hard
A 27-year-old man has a testicular mass. Before orchiectomy: AFP 640 µg/L (reference < 10), hCG 85 IU/L (reference < 2), LD mildly raised; liver tests normal. The pathology report describes pure seminoma. Which conclusion do the markers best support?
1. AA nonseminomatous component is likely present
2. BThese markers are typical of pure seminoma
3. CThe AFP was produced by the seminoma cells
4. DThe raised hCG proves a choriocarcinoma
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Answer: A · A nonseminomatous component is likely present
Pure seminomas do not produce AFP, although a minority secrete modest amounts of hCG from syncytiotrophoblastic cells. A clearly raised AFP, with liver disease excluded, means a nonseminomatous element such as yolk sac tumor is present, even if the sections examined looked like seminoma. The tumor is then staged and treated as a nonseminomatous germ cell tumor. AFP, hCG and LD are measured before orchiectomy and followed afterward to check that they fall as expected.
- B: A clearly raised AFP is not expected in pure seminoma.
- C: Seminoma cells do not make AFP; yolk sac elements do.
- D: Seminomas can secrete modest hCG, so hCG alone does not prove choriocarcinoma.
Question 4 · Easy
In colorectal cancer care, serial serum CEA results add the most value when they are used for:
1. AScreening adults at average risk for colorectal cancer
2. BMonitoring ovarian cancer during chemotherapy
3. CConfirming the diagnosis of colorectal cancer
4. DDetecting recurrence after colorectal cancer surgery
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Answer: D · Detecting recurrence after colorectal cancer surgery
CEA is raised in many colorectal cancers, especially advanced ones, but also in smokers and in benign conditions such as inflammatory bowel disease, cirrhosis and pancreatitis. It is too insensitive for early cancer and too nonspecific for screening or diagnosis. Its main use is a baseline before surgery and serial measurements afterward: a level that falls to normal and then rises suggests recurrence or metastasis. The same assay should be used for every result in the series.
- A: CEA is often normal in early cancer and raised in benign conditions, so it is not a screening test.
- B: Ovarian cancer is monitored with CA 125, not CEA.
- C: Diagnosis needs colonoscopy and biopsy; CEA cannot confirm cancer.
Question 5 · Medium
A 66-year-old man has taken finasteride for benign prostatic enlargement for 2 years. His PSA is 2.1 µg/L (2.1 ng/mL). How should this result be interpreted?
1. AIt is about double the value expected without the drug
2. BIt cannot be interpreted until the drug is stopped
3. CIt is about half the value expected without the drug
4. DIt is unaffected, because finasteride does not alter PSA
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Answer: C · It is about half the value expected without the drug
Finasteride and dutasteride block 5-alpha-reductase, lowering dihydrotestosterone and shrinking prostate tissue. After 6 to 12 months of treatment, PSA falls by about half, so a common rule is to double the measured value before comparing it with the usual cut-offs. A PSA that rises while the patient is on stable treatment deserves investigation. The request should record such drugs so that the laboratory and clinician can interpret the result.
- A: The drug lowers PSA; it does not raise it.
- B: PSA can still be followed on treatment by allowing for the expected fall.
- D: 5-alpha-reductase inhibitors lower PSA by about half after several months.
Question 6 · Hard
A 61-year-old nonsmoker had a colon cancer removed. CEA (reference < 5.0 µg/L): 38 before surgery; 2.4 at 6 weeks; then 3.1, 5.6 and 11.8 at 3-month intervals on the same assay. What is the best interpretation?
1. AThe rise reflects slow clearance of the preoperative CEA
2. BThe steady rise after normalizing suggests recurrence
3. COnly a result above the preoperative level would matter
4. DValues far below the preoperative level show remission
Answer and explanation in LearnFree account
Question 7 · Easy
After a hydatidiform mole is evacuated, which marker is followed until it becomes undetectable?
1. ACA 125
2. BCEA
3. ChCG
4. DAFP
Answer and explanation in LearnFree account
Question 8 · Medium
CA 125 is not recommended to screen women at average risk for ovarian cancer, mainly because it:
1. AIs made only by mucinous, not serous, ovarian tumors
2. BIs raised only in women past the menopause
3. CRises only after the cancer has spread to the liver
4. DIs often normal in early cancer and raised in benign disease
Answer and explanation in LearnFree account
Question 9 · Easy
Which tumor marker is mainly used to monitor epithelial ovarian cancer?
1. ACA 15-3
2. BCA 125
3. CPSA
4. DAFP
Answer and explanation in LearnFree account

Tumor markers

A man on surveillance for prostate cancer has had PSA results of 4.1, 4.3 and 4.2 µg/L (ng/mL) over 18 months on one assay. The laboratory then changes to another manufacturer's PSA assay, and his next result is 5.0 µg/L. What is the best response?

A 27-year-old man has a testicular mass. Before orchiectomy: AFP 640 µg/L (reference < 10), hCG 85 IU/L (reference < 2), LD mildly raised; liver tests normal. The pathology report describes pure seminoma. Which conclusion do the markers best support?

In colorectal cancer care, serial serum CEA results add the most value when they are used for:

A 66-year-old man has taken finasteride for benign prostatic enlargement for 2 years. His PSA is 2.1 µg/L (2.1 ng/mL). How should this result be interpreted?

A 61-year-old nonsmoker had a colon cancer removed. CEA (reference < 5.0 µg/L): 38 before surgery; 2.4 at 6 weeks; then 3.1, 5.6 and 11.8 at 3-month intervals on the same assay. What is the best interpretation?

After a hydatidiform mole is evacuated, which marker is followed until it becomes undetectable?

CA 125 is not recommended to screen women at average risk for ovarian cancer, mainly because it:

Which tumor marker is mainly used to monitor epithelial ovarian cancer?