Urology: PSA interpretation on a 5-alpha reductase inhibitor: practice question

A General Surgery question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Surgery · Urology: PSA interpretation on a 5-alpha reductase inhibitor

Sample item

A 64-year-old man has taken finasteride for his prostate for 18 months. His PSA is now 3.0 ng/mL. How should this value be interpreted?

AIt is unreliable because PSA cannot be measured on finasterideBIt is equivalent to about 1.5 ng/mL and is reassuringCIt is normal for his age and needs only routine follow-upDIt is equivalent to about 6 ng/mL and warrants evaluation for prostate cancer

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. It is equivalent to about 6 ng/mL and warrants evaluation for prostate cancer

5-alpha reductase inhibitors lower PSA by roughly half after six to twelve months, so the measured value is doubled to estimate the true value. A PSA of 3.0 on treatment corresponds to about 6.0, which would prompt further assessment.

Option by option

A. It is unreliable because PSA cannot be measured on finasteride
PSA can be measured, and a sustained rise on treatment is itself significant.
B. It is equivalent to about 1.5 ng/mL and is reassuring
Halving the value is the wrong direction; the drug lowers PSA, so the true value is higher.
C. It is normal for his age and needs only routine follow-up
Taking the value at face value ignores the drug effect and may delay diagnosis.
D. It is equivalent to about 6 ng/mL and warrants evaluation for prostate cancer (correct)
Correct. The value is doubled on a 5-alpha reductase inhibitor, giving about 6 ng/mL.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is D, It is equivalent to about 6 ng/mL and warrants evaluation for prostate cancer. 5-alpha reductase inhibitors lower PSA by roughly half after six to twelve months, so the measured value is doubled to estimate the true value.

Why is "It is unreliable because PSA cannot be measured on finasteride" not the answer?

PSA can be measured, and a sustained rise on treatment is itself significant.

Why is "It is equivalent to about 1.5 ng/mL and is reassuring" not the answer?

Halving the value is the wrong direction; the drug lowers PSA, so the true value is higher.

Why is "It is normal for his age and needs only routine follow-up" not the answer?

Taking the value at face value ignores the drug effect and may delay diagnosis.

What concept does this question test?

It tests Urology: PSA interpretation on a 5-alpha reductase inhibitor in General Surgery. A PSA of 3.0 on treatment corresponds to about 6.0, which would prompt further assessment.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Urology: PSA interpretation on a 5-alpha reductase inhibitor?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.