International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1994
Serum prostate-specific antigen after radiation therapy for clinically localized prostate cancer: prognostic implications.
Serum prostate-specific antigen (PSA) levels following definitive radiation for prostate cancer are increasingly recognized as the most sensitive means to monitor disease status. However, beyond general agreement that patients fare poorly when posttreatment PSA levels fail to normalize, many questions relative to postirradiation PSA remain unanswered. This study evaluates the potential prognostic value of postirradiation PSA in a large cohort of patients followed with serial PSA determinations. ⋯ The nadir PSA value after radiation is a significant posttreatment determinant of outcome and was second only to the pretreatment value. Surprisingly low nadir values were prognostically significant. Only patients whose nadir falls below 1 ng/ml can be said to have achieved a biochemical complete remission. However, even such low nadir values do not portend durable disease control for patients with high pretreatment PSA levels.