The pattern of prostate-specific antigen responses following hormonal therapy in Thai men with bone metastatic prostate cancer.

OBJECTIVE

To study the pattern of prostate-specific antigen (PSA) responses and prognostic factors following hormonal therapy in Thai men with bone metastatic prostate cancer.

MATERIAL AND METHOD

Forty-four patients with bone metastatic prostate cancer treated by bilateral orchiectomy were retrospectively studied for PSA responses during follow-up. The endpoint was time to PSA biochemical failure. PSA pattern and the prognostic factors were evaluated.

RESULTS

PSA levels regressed to PSA nadir level in all patients. Time to 50 per cent PSA regression, time to PSA nadir level and time to biochemical failure were 2.1, 6.7 and 11.2 months, respectively. While biochemical failure was present, all patients were alive and had stable clinical conditions. Tumor grading was an important prognostic factor while age and pretreatment PSA level were not a significant indicator. Times to biochemical failure in the patients with well, moderate and poor differentiated tumors were 19.3, 10.0 and 9.3 months, respectively.

CONCLUSION

Following bilateral orchiectomy in Thai men with bone metastatic prostate cancer, PSA level decreased continuously to the PSA nadir level in 6-7 months and stable for a period then it increased, known as biochemical failure. The patients with a well differentiated tumor had a significantly longer time to biochemical failure when compared to the patients with a moderate or poor differentiated tumor.