title: Radical radiation therapy in the management of prostatic adenocarcinoma: the initial prostate specific antigen value as a predictor of treatment outcome.
abstract: We studied 161 prostate cancer patients treated by radical irradiation alone without endocrine therapy in whom pretreatment and posttreatment prostate specific antigen (PSA) values were measured, and who had a minimum followup of 2 years. Outcome was analyzed in an actuarial fashion using clinical disease-free survival and biochemical disease-free survival (freedom from an increasing PSA level or a PSA level of greater than 1.0 ng./ml. 2 years following irradiation) as end points. Of the patients 54% achieved a post-irradiation nadir value in the range 0 to 1.0 ng./ml. and 29% had a nadir value that was undetectably low (less than 0.5 ng./ml.). The likelihood of achieving these values was greater among patients with early stage than locally advanced tumors. For all T stages the likelihood of being disease-free at 4 years was substantially and significantly lower when PSA was used as an end point than when clinical evaluation alone was used: stages T1 and T2 (85 patients) 41% versus 71%, and stages T3 and T4 (76 patients) 15% versus 61%. For the whole group at 4 years clinical control was 67% but biochemical control was only 26% (p < 0.05). The likelihood of being free of biochemical evidence of persistent disease at 4 years was a function of the initial PSA value (PSA less than 4.0 in 81% of the cases, 4.1 to 10.0 in 43%, 10.1 to 20.0 in 31%, 20.1 to 50.0 in 6% and greater than 50.0 in 0%). For stages T1 and T2 cancer patients with an initial PSA level of less than 15 ng./ml. (67% of all early stage cases) this value was 65% and it was even higher (73%) when poorly differentiated tumors were excluded. When the initial PSA level for stages T1 and T2 tumors was greater than 15 ng./ml. the projected 4-year rate of freedom from biochemical failure was only 7%. For stages T3 and T4 cancer patients the corresponding figures were 39% for those with an initial PSA level of less than 15 ng./ml. and 0% for those with an initial PSA level of greater than 15 ng./ml. The prognostic power of the initial PSA level was independent of stage, grade, patient age and prior transurethral resection of the prostate in a multivariate analysis. An initial serum PSA level of more than 15 ng./ml. is, therefore, a powerful predictor of probable failure with conventional radiation therapy. Serum PSA monitoring is a sensitive detector of early relapse.(ABSTRACT TRUNCATED AT 400 WORDS)
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
authors.forename: A L
authors.initials: AL
authors.lastname: Zietman
authors.forename: J J
authors.initials: JJ
authors.lastname: Coen
authors.forename: W U
authors.initials: WU
authors.lastname: Shipley
authors.forename: C G
authors.initials: CG
authors.lastname: Willett
authors.forename: J T
authors.initials: JT
authors.lastname: Efird
mesh_terms: D000206:Actuarial Analysis; D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen