Influence of radioimmunoscintigraphy on postprostatectomy radiotherapy treatment decision making.
The aim of this study was to evaluate the role of radioimmunoscintigraphy (RIS) directed against prostate-specific membrane antigen (PSMA) in influencing postradical retropubic prostatectomy (RRP) radiotherapy (RT) decision making.


METHODS
The records of consecutive patients who underwent RRP, who were referred for consideration of RT, and for whom an RIS scan was obtained were reviewed. The RT decisions, with regard to (a) the decision to offer RT and (b) the general volume to be treated [prostate fossa (PF) only versus PF + pelvis (P)] before knowledge of the RIS findings were charted. The RIS findings, with regard to uptake in the PF, uptake in the P, or extrapelvic (EP) uptake were tabulated. Then, the RT treatment decisions based on the RIS knowledge were evaluated and compared with the pre-RIS RT treatment decisions.


RESULTS
Of the 54 patients originally referred for post-RRP RT, the initial decision was to recommend RT to the PF only in 52 cases and to PF+P in 2 cases. The RIS findings were as follows: PF only, 43 patients; PF+P, 8 patients; PF+EP, 2 patients; PF+P+EP, 1 patient. After knowledge of these RIS results, the decision to offer RT was withdrawn in 4 of 54 patients (7.4%; P = 0.046). Furthermore, RIS changed the general treatment volume (PF only to PF+P) in 6 of 54 patients (11.1%; P = 0.015). In total, RIS altered the RT decision in 10 of 54 patients (18.5%; P = 0.0067). Three-year biochemical failure-free survival (with failure defined as 2 consecutive prostate-specific antigen [PSA] rises above 0.2 ng/mL after PSA nadir) was 78%; no patient, disease, or treatment factor reached statistical significance on univariate or multivariate analysis.


CONCLUSIONS
RIS was found to influence post-RRP RT decision making for the identification of patients not likely to benefit from RT and for guiding general target volume definition.
Jani
Ashesh B
AB
Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois, USA. jani_1969@yahoo.com
Blend
Michael J
MJ
Hamilton
Russell
R
Brendler
Charles
C
Pelizzari
Charles
C
Krauz
Lani
L
Vijayakumar
Srinivasan
S
Sapra
Bipin
B
Awan
Azhar
A
Weichselbaum
Ralph R
RR
D000368:Aged; D000369:Aged, 80 and over; D003658:Decision Making, Computer-Assisted; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011182:Postoperative Care / Q000379:methods*; D010818:Practice Patterns, Physicians'; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000601:surgery; D016719:Radioimmunodetection / Q000379:methods*; D018570:Risk Assessment / Q000379:methods*
D017430:Prostate-Specific Antigen