A prospective study of prostate specific antigen levels in patients receiving radiotherapy for localized carcinoma of the prostate

• Published in: International journal of radiation oncology, biology, physics Vol. 19; no. 3; pp. 733 - 741
• Main Authors: Meek, Allen G., Park, Tae L., Oberman, Eric, Wielopolski, L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY Elsevier Inc 01.09.1990; Elsevier
• Subjects: Aged; Aged, 80 and over; Antigens, Neoplasm - blood; Biological and medical sciences; Biomarkers, Tumor - blood; Diseases of the urinary system; Half-Life; Humans; Male; Medical sciences; Middle Aged; Prospective Studies; Prostate-Specific Antigen; Prostatic neoplasms; Prostatic Neoplasms - chemistry; Prostatic Neoplasms - epidemiology; Prostatic Neoplasms - radiotherapy; Radiotherapy; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Tumor markers; Radiotherapy; Prostatic neoplasms; Tumor markers; Human; Tumor; Urinary system disease; Treatment; Prostatic disease
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/0360-3016(90)90504-D

Prostate Specific Antigen (PSA) is becoming the preferred tumor marker in the management of prostate cancer. Prostate Specific Antigen levels fall exponentially after radical prostatectomy with a half-life of between 2 and 3 days. Persistently elevated Prostate Specific Antigen levels beyond 7 half-lives suggest occult residual disease and may serve as an indication for post operative adjunctive therapy. The change in Prostate Specific Antigen levels during a course of radical external beam radiotherapy for prostate cancer has not been described. In this study of 81 patients receiving radiotherapy for primary prostate cancer, 47 had elevated Prostate Specific Antigen levels prior to therapy and 35 had serial measurement of Prostate Specific Antigen during their course of treatment. Working on an assumption that in patients with radioresponsive localized prostate cancer Prostate Specific Antigen levels will fall exponentially during the radiotherapy, a half-life of 43 ± 11 days was derived. Prostate Specific Antigen half-life appears independent of stage, grade, or pretreatment Prostate Specific Antigen level and may be an independent prognostic indicator. A prolonged Prostate Specific Antigen half-life may suggest untreated or resistant disease and serve as an indication for adjuvant hormonal treatment in patients receiving radiotherapy for primary prostate cancer.