The Value of PSA as a Molecular Predictor of Bony Metastasis in Prostatic Cancer

Byeon, Seok Seo; Park, Run Chan; Kim, Yong Tai; Park, Moon Soo; Lee, Sang Eun

Abstract

To evaluate the correlation between serum PSA(prostate specific antigen) levels and bone metastasis and to identify better criteria for the selection of appropriate candidates for bone scan, we reviewed the medical records of 53 patients with prostatic adenocarcinoma who were managed at Seoul National University Hospital from January 1990 to December 1993. PSA was measured by monoclonal radioimmunometric assay.(ELSA PSA) Histologic grade, tumor stage as well as status of metastasis were compared with the level of PSA. We stratified bony lesions which were evaluated with bone scan into extent of disease(EOD). The PSA level increased as tumor stage increased but this was not statistically significant. There was positive correlation between the PSA level and Gleason sum. The mean value of PSA in the group of non-metastasis was 106.2ng/ml compared to 711.8ng/ml in the group with metastasis. This was statistically significant. There was no correlation between the PSA level and extent of disease but PSA levels of EOD 1 group was significantly lower than those of remaining group. When we stratified patients with bony metastasis according to the PSA level, only 1 of 13 patients with PSA of 20ng/ml or less had bony metastasis. Its negative predictive value was 92.3%. In conclusion, patients with PSA of 20ng/ml or less are not likely to have bony metastasis. Further large-scaled prospective study is needed to determine the predictability of PSA for bony metastases more accurately.