PROSTATIC-SPECIFIC ANTIGEN DOUBLING TIMES IN PATIENTS WITH PROSTATE-CANCER - A POTENTIALLY USEFUL REFLECTION OF TUMOR DOUBLING TIME

Purpose: This study was undertaken to investigate the relationship of prostatic specific antigen doubling time with disease progression in irradiated patients whose only sign of failure was an abnormal prostatic specific antigen. Methods and Materials: Post irradiation patients whose only sign of failure was an elevated prostatic specific antigen were followed without treatment. The prostatic specific antigen doubling time was determined and compared to original characteristics of disease, time to elevation of prostatic specific antigen after treatment and time to a second sign of failure. Results: The prostatic specific antigen doubling times varied from 1.2 months to 36 months. The original grade and stage correlated with the doubling time as did the intervals to elevation of prostatic specific antigen and to a second sign of failure. Conclusion: We recommend delaying intervention until the prostatic specific antigen doubling time can be calculated for patients with prostatic specific antigen elevation as the only sign of failure. Patients with short doubling times (< 9 months) can be promptly treated while those with longer doubling times (> 1 year) may have androgen suppression delayed avoiding the cost and morbidity of that treatment.