Biochemical Relapse-Free Survival in Postprostatectomy Patients Receiving 18F-Fluciclovine-Guided Prostate Bed-Only Radiation: Post Hoc Analysis of a Prospective Randomized Trial.
Pract Radiat Oncol
; 2024 Jul 20.
Article
em En
| MEDLINE
| ID: mdl-39032598
ABSTRACT
PURPOSE:
Whole-pelvis (WP) radiation therapy (radiation) improved biochemical relapse-free survival (bRFS) compared with prostate bed (PB)-only radiation in the Radiation Therapy Oncology Group 0534, but was performed in an era prior to positron emission tomography (PET) staging. Separately, 18F-fluciclovine PET/CT-guided postprostatectomy radiation improved 3-year bRFS versus radiation guided by conventional imaging alone. We hypothesized that patients who were changed from WP to PB-only radiation after PET would have bRFS that was (a) no higher than patients initially planned for PB-only radiation; and (b) lower than patients planned for WP radiation without PET guidance. METHODS AND MATERIALS We conducted a post hoc analysis of a prospective, randomized trial comparing conventional (arm 1) versus PET-guided (arm 2) postprostatectomy radiation. In arm 2, pre-PET treatment field decisions were recorded and post-PET fields were defined per protocol; pathologic node negative (pN0) without pelvic or extrapelvic PET uptake received PB-only radiation. Three-year bRFS was compared in patients planned for WP with change to PB-only radiation (arm 2 [WPPB]) vs arm 2 patients planned for PB-only with final radiation to PB-only (arm 2 [PBPB]) and arm 1 pN0 patients treated with WP radiation (arm 1 [WP]) using the Z test and log-rank test. Demographics were compared using the chi-square test, Fisher exact test, or analysis of variance, as appropriate.RESULTS:
We identified 10 arm 2 (WPPB), 31 arm 2 (PBPB) and 11 arm 1 (WP) patients. Androgen deprivation was used in 50.0% of arm 2 (WPPB) and 3.2% of arm 2 (PBPB) patients, P < .01. Median preradiation prostate-specific antigen was higher in arm 2 (WPPB) vs arm 2 (PBPB) patients (0.4 vs 0.2 ng/mL, P = .03); however, there were no significant differences in T stage, Gleason score, or margin positivity. Three-year bRFS was 80% in arm 2 (WPPB) vs 87.4% in arm 2 (PBPB), P = .47, respectively. Arm 1(WP) patients had significantly worse 3-year (23%) bRFS vs arm 2 (WPPB), P < .01.CONCLUSIONS:
Patients initially planned for WP radiation with field decision change to PB-only radiation after PET showed (1) no significant difference in 3-year bRFS compared with patients initially planned for PB-only radiation; and (2) improved bRFS compared with patients receiving WP radiation without PET guidance. PET-guided volume de-escalation in selected patients may be 1 approach to mitigating toxicity without compromising outcomes.
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MEDLINE
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Ano de publicação:
2024
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Article