Measurement of serum prostate specific antigen levels in women and in prostatectomized men with an ultrasensitive immunoassay technique.

Serum prostate specific antigen (PSA) was measured in 89 prostate cancer patients with no evidence of relapse after radical prostatectomy, in 387 hospitalized women with various diseases and in 674 apparently healthy female blood donors, using an ultrasensitive time resolved immunofluorometric assay with a biological detection limit of 0.01 microgram./l. Of the prostatectomized cancer patients 50% had measurable PSA (0.010 microgram./l. or greater) and 21% had levels of 0.050 microgram./l. or greater. Postoperative PSA was not associated with year of surgery, preoperative PSA or histological grade of the tumors. The distribution of PSA in 1,064 female sera is also reported, of which 83% had no detectable serum PSA, and in 15% PSA was between 0.010 and 0.049 microgram./l. Only 27 subjects (2.5%) had PSA levels of 0.050 microgram./l. or greater, including 16 (1.5%) with PSA of 0.10 microgram./l. or greater. High serum PSA in women was associated with age 50 years or older. Further studies are needed to examine if the difference in PSA levels between women and prostatectomized men is due to residual or recurrent tumor or to other reasons associated with gender.