IMAT 2012 Q12 [Prostate Cancer]

Approximately 1 in 14 men over the age of 50 has prostate cancer. The level of ‘prostate specific antigen’ (PSA) is used as a preliminary screening test for prostate cancer.

7% of men with prostate cancer do not have a high level of PSA. These results are known as ‘false negatives’.

75% of those men with a high level of PSA do not have cancer. These results are known as ‘false positives’.

If a man over 50 has a normal level of PSA, what are the chances that he has prostate cancer?

A. 7%
B. 25%
C. 5%
D. 0.7%
E. 0.5%