Feasibility of MR imaging/MR spectroscopy-planned focal partial salvage permanent prostate implant (PPI) for localized recurrence after initial PPI for prostate cancer.
OBJECTIVE
To assess the feasibility of magnetic resonance imaging (MRI)-planned partial salvage permanent prostate implant (psPPI) among patients with biopsy-proven local recurrence after initial PPI without evidence of distant disease.


METHODS
From 2003-2009, 15 patients underwent MRI/magnetic resonance spectroscopy (MRS) planning for salvage brachytherapy (psPPI, I-125 [n=14; 144 Gy]; Pd-103 [n=1; 125 Gy]) without hormone therapy. Full dose was prescribed to areas of recurrence and underdosage, without entire prostate implantation. Limiting urethral and rectal toxicity was prioritized. Follow-up was from salvage date to prostate-specific antigen (PSA) concentration failure (Phoenix criteria = nadir + 2.0; ASTRO = 3 consecutive rises), recurrence, distant metastases, or last follow-up PSA level. Progression-free survival (PFS) was defined as no PSA failure or biopsy-proven recurrence without all-cause mortality. Toxicity was scored using Common Terminology Criteria for Adverse Events version 4.0.


RESULTS
At salvage, median age was 68 years, and PSA concentration was 3.5 ng/mL (range, 0.9-5.6 ng/mL). Abnormal MRI/MRS findings were evident in 40% of patients. Biopsy-proven recurrences consisted of a single focus (80%) or 2 foci (20%). At recurrence, Gleason score was 6 (67%) or ≥7 (27%). Median interval between initial and salvage implantation was 69 months (range, 28-132 months). psPPI planning characteristics limited doses to the rectum (mean V100 = 0.5% [0.07 cc]) and urethra (V100 = 12% [0.3 cc]). At median follow-up (23.3 months; range, 8-88 months), treatment failure (n=2) resulted only in localized recurrence; both patients underwent second psPPI with follow-up PSA tests at 12 and 26 months, resulting in 0.6 and 0.7 ng/mL, respectively. American Society for Radiation Oncology PFS rates at 1, 2, and 3 years were 86.7%, 78.4%, and 62.7%, respectively, with 5 patients for whom treatment failed (n=3 with negative transrectal ultrasound-guided biopsy results). Phoenix PFS rates at 1, 2, and 3 years were 100%, 100%, and 71.4%. 73%, respectively; achieved PSA nadir of <0.5 ng/mL; and 47% of patients had a nadir of <0.1 ng/mL. Treatment-related toxicity was minimal, with no operative interventions, fistulas, or other grade ≥3 gastrointestinal (GI)/genitourinary (GU) toxicity. Thirteen percent had grade 1 GI and 33% had grade 2 GU toxicities. Postsalvage, 20% of patients had no erectile dysfunction, 67% of patients had medication-responsive erectile dysfunction, and 13% of patients had erectile dysfunction refractory to medication.


CONCLUSIONS
Focal psPPI with MR-planning in highly selected patients is feasible with short-term control comparable to conventional salvage, with less toxicity. Longer follow-up is needed to confirm its impact on quality of life and treatment.
Department of Radiation Oncology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, California 94115, USA. hsucc@radonc.ucsf.edu
Charles C
CC
Hsu
Howard
H
Hsu
Barby
B
Pickett
Gilles
G
Crehange
I-Chow Joe
IC
Hsu
Ryan
R
Dea
Vivian
V
Weinberg
Alexander R
AR
Gottschalk
John
J
Kurhanewicz
Katsuto
K
Shinohara
Mack
M
Roach
D000368:Aged; D001706:Biopsy; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D018572:Disease-Free Survival; D005240:Feasibility Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D058958:Organs at Risk / Q000528:radiation effects; D010165:Palladium / Q000627:therapeutic use; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000517:prevention & control; D011868:Radioisotopes / Q000627:therapeutic use; D012007:Rectum / Q000528:radiation effects; D016879:Salvage Therapy / Q000009:adverse effects / Q000379:methods*; D014521:Urethra / Q000528:radiation effects
D011868:Radioisotopes; D010165:Palladium; D017430:Prostate-Specific Antigen