[Molecular forms of PSA and differentiating between benign hypertrophy,carcinoma, and disseminated prostatic carcinoma. Correlation between two determination technics].

OBJECTIVE

To determine the correlation between two methods of measurement of total PSA (PSA-T) and free PSA (PSA-F) and the utility of the PSA-F/PSA-T ratio in patients with PSA-T between 4 and 10 ng/ml suspected as having prostate cancer.

METHODS

Determinations of both PSA-T and PSA-F were performed using two different techniques in 91 patients suspected as having prostate cancer. Diagnosis was made on the findings of biopsy and the complementary tests.

RESULTS

The following correlation was found for the two techniques: R = 0.99 and p < 0.05 for PSA-T, and R = 0.85 and p < 0.05 for PSA-F. For PSA-T values of 4-10 ng/ml and PSA-F greater than 25%, we found two patients with prostate cancer. For a PSA-F/PSA-T ratio less than 9%, all cases had prostate cancer. Three cases with bone metastasis had PSA-T values less than 10 ng/ml.

CONCLUSIONS

A PSA-F/PSA-T ratio greater than 25% does not exclude malignancy in patients with a total PSA of 4-10 ng/ml; values less than 9% correspond to prostate cancer. Bone metastasis was found with both methods in patients with total PSA values less than 10 ng/ml.