Prostate-specific antigen: effect of pelvic irradiation

• Published in: Radiology Vol. 215; no. 3; p. 757
• Main Authors: Gripp, S, Haller, J C, Metz, J, Willers, R
• Format: Journal Article
• Language: English
• Published: United States 01.06.2000
• Subjects: Anus Neoplasms - blood; Anus Neoplasms - radiotherapy; Combined Modality Therapy; Follow-Up Studies; Humans; Male; Pelvis - radiation effects; Prostate-Specific Antigen - blood; Prostate-Specific Antigen - radiation effects; Radiotherapy Dosage; Rectal Neoplasms - blood; Rectal Neoplasms - radiotherapy; Statistics, Nonparametric; Time Factors
• ISSN: 0033-8419
• DOI: 10.1148/radiology.215.3.r00jn09757

To study the effect of pelvic irradiation on the level of serum prostate-specific antigen (PSA). Of 33 patients treated with pelvic irradiation to the prostate and seminal vesicles for anal and rectal cancer, 26 received 50.4 Gy or more (1. 8 Gy per fraction), and seven received 25.0 Gy (5.0 Gy per fraction). PSA levels were measured before (n = 33), during (n = 26), and after radiation therapy (n = 33). In 24 patients, follow-up (mean, 15.7 months) PSA data were obtained. Actual and pretreatment PSA levels were compared (Wilcoxon rank test). During the first 3 weeks in all patients, PSA levels rose steeply, culminating in a 3. 7-fold increase (P =.02). At the end of radiation therapy (7 weeks), the PSA level was no longer significantly different from the pretreatment value. In the long term, the PSA level decreased to 77% of the pretreatment value (P =.04). Irradiation of the prostate initially elevates serum PSA levels. Apparently PSA release is determined by the duration of radiation therapy, while the accumulated dose has a minor effect. In the long term, PSA production is impaired after radical radiation therapy. PSA reference concentrations should be adjusted to these reduced levels.