(68)Ga-PSMA ligand PET/CT-based radiotherapy in locally recurrent and recurrent oligometastatic prostate cancer : Early efficacy after primary therapy.
OBJECTIVE
The goal of this work was to evaluate the early efficacy of (68)Ga-PSMA ligand PET/CT imaging for radiotherapy of locally recurrent and/or oligometastatic prostate cancer.


METHODS
A total of 29 patients with biochemical recurrence received a (68)Ga-PSMA ligand PET/CT for restaging of disease, followed by 3D conformal radiotherapy of metastases or intensity-modulated radiation therapy of the prostate bed. Prostate-specific antigen (PSA) levels and imaging procedures served as the reference standard to assess the treatment efficacy.


RESULTS
PET/CT was positive in 96.6% of patients and revealed that 13.8% of patients had locally recurrent disease, 58.6% had isolated lymph node metastases, 20.7% had isolated bone metastases, and 3.4% showed lymph node metastases and a vertebral metastasis. The median follow-up was 8.3 months (range 3.0-17.3 months). The median PSA prior to radiotherapy was 1.47 ng/ml (range 0.52-32.01 ng/ml) and showed a statistically significant decrease to 0.58 ng/ml (range < 0.07 to 6.33 ng/ml, p < 0.001). Two patients (6.8%) developed progressive disease outside the radiation field after 12.0 and 12.7 months, yielding a local control rate of 100% at the median follow-up. No grade III acute toxicity or late toxicity grade II was observed. Only 2 patients (6.8%) reported persisting grade I diarrhoea according to the LENT-SOMA criteria 3 months after radiotherapy. Deterioration of the urinary or faecal continence was not observed.


CONCLUSIONS
Preliminary results in the presented cohort suggest that radiotherapy based on (68)Ga-PSMA ligand PET/CT yields effective local control and significant treatment response in terms of PSA levels in the absence of clinically important side effects. Furthermore, this approach delayed the necessity of androgen deprivation therapy or systemic therapy.
Department of Radiation and Special Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. henkenberens.christoph@mh-hannover.de.
Christoph
C
Henkenberens
Department of Urology and Urologic Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Christoph A
CA
von Klot
Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Tobias L
TL
Ross
Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Frank M
FM
Bengel
Pharmaceutical Radiochemistry, Technische Universität München, Walther-Meißner-Str. 3, 85748, Garching, Germany.
Hans-Jürgen
HJ
Wester
Department of Urology, University Hospital Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
Axel S
AS
Merseburger
Department of Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Jens
J
Vogel-Claussen
Department of Radiation and Special Oncology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Hans
H
Christiansen
Department of Nuclear Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Thorsten
T
Derlin
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D004492:Edetic Acid / Q000031:analogs & derivatives; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000175:diagnosis / Q000532:radiotherapy*; D009842:Oligopeptides; D009942:Organometallic Compounds; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000532:radiotherapy*; D019275:Radiopharmaceuticals; D018714:Radiotherapy, Adjuvant / Q000379:methods; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D016896:Treatment Outcome
D014408:Biomarkers, Tumor; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid; D017430:Prostate-Specific Antigen
Androgen deprivation therapy; Local control; Neoplasm recurrence, local; Prostate-specific antigen; Prostatic neoplasms