Salvage external beam radiotherapy for recurrent prostate adenocarcinoma after high-intensity focused ultrasound as primary treatment.
BACKGROUND
The main objective was to evaluate feasibility, toxicity and biochemical control rates of salvage external beam radiotherapy (EBRT) in recurrent localized prostate cancer after high-intensity focused ultrasound (HIFU) as primary therapy.


METHODS
A total of 24 patients who underwent salvage EBRT after 1 or 2 HIFU sessions and with a minimum post-treatment follow-up of 24 months were retrospectively evaluated. Primary endpoints were toxicity and biochemical disease-free survival (bDFS, defined according to the ASTRO Phoenix definition).


RESULTS
Median follow-up was 40.3 months. Gastrointestinal toxicity was low. Acute genitourinary (GU) toxicity grade ≤II rate was 45.8%, with only few patients presenting grade III (8.3%) and grade IV (4.2%) toxicity. Late grade ≥III GU toxicity was registered in 16.7% of patients. The 3-year bDFS rate was 77.8%. Patients achieving a nadir prostate-specific antigen (nPSA) of ≤0.35 ng/ml after EBRT had significantly higher bDFS (3-year bDFS: 87.7 vs. 50%, respectively; p = 0.001). Achieving nPSA ≤0.35 ng/ml was the only factor independently associated to long-term bDFS both on univariate (p = 0.01) and multivariate analysis (HR 7.06, p = 0.039).


CONCLUSIONS
Salvage EBRT after HIFU failure is feasible and allows to obtain satisfactory biochemical control rates, especially in patients attaining a nPSA ≤0.35 ng/ml after EBRT.
University of Torino, Department of Oncology, Radiation Oncology Unit, Turin, Italy.
Fernando
F
Munoz
Alessia
A
Guarneri
Angela
A
Botticella
Pietro
P
Gabriele
Francesco
F
Moretto
Rocco
R
Panaia
Andrea
A
Ruggieri
Leonardo
L
D'Urso
Giovanni
G
Muto
Andrea Riccardo
AR
Filippi
Riccardo
R
Ragona
Umberto
U
Ricardi
D000230:Adenocarcinoma / Q000097:blood / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005240:Feasibility Studies; D057086:High-Intensity Focused Ultrasound Ablation; D006801:Humans; D007610:Kallikreins / Q000097:blood; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012189:Retrospective Studies; D012307:Risk Factors; D016879:Salvage Therapy; D013997:Time Factors; D017211:Treatment Failure
C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen