Cg. Ramos et al., The effect of high grade prostatic intraepithelial neoplasia on serum total and percentage of free prostate specific antigen levels, J UROL, 162(5), 1999, pp. 1587-1590
Purpose: It is established that the percentage of free prostate specific an
tigen (PSA) in serum is low in patients with prostate cancer. An unanswered
question is whether a low percentage of free PSA can be explained by high
grade prostatic intraepithelial neoplasia alone. We compared the percentage
of free PSA in men with high grade prostatic intraepithelial neoplasia alo
ne, prostate cancer, benign prostatic hyperplasia (BPH) and a normal prosta
te (that is normal digital rectal examination and PSA less than or equal to
2.5 ng./ml.).
Materials and Methods: From October 1994 through December 1997, 48 men were
diagnosed with high grade prostatic intraepithelial neoplasia without conc
omitant prostate cancer. Of these men 43 with a mean age plus or minus stan
dard deviation of 67.4 +/- 7.8 years comprised our study group. To date non
e has been diagnosed with cancer during followup. Serum free and total PSA
levels were measured, and the percentage of free SA was calculated. The per
centage of free PSA in the 43 men was compared to that in 50 with prostate
cancer (mean age 65.4 +/- 7.8 years), 50 with biopsy proved BPH (67 +/- 7)
and 43 with a normal prostate (61 +/- 8).
Results: There was no significant difference in mean total serum PSA in pat
ients with high grade prostatic intraepithelial neoplasia, prostate cancer
or BPH. The percentage of free PSA was significantly lower in patients with
prostate cancer (14.9 +/- 6.5%) than those with high grade prostatic intra
epithelial neoplasia (20.8 +/- 7.1%), BPH (20.1 +/- 7.3%) or a normal prost
ate (27.7 +/- 12.2%). There was also no significant difference in the perce
ntage of free PSA between men with high grade prostatic intraepithelial neo
plasia (20.8 +/- 7.1%) and those with BPH (20.1 +/- 7.3%). Additionally, me
n with a normal prostate had a higher percentage of free PSA (27.7%) than t
hose with BPH (20.1%), high grade prostatic intraepithelial neoplasia (20.8
%) or prostate cancer (14.9%).
Conclusions: The percentages of free PSA in men with high grade prostatic i
ntraepithelial neoplasia and BPH are similar, and significantly higher than
those found in men with prostate cancer.