68Ga-PSMA-PET for radiation treatment planning in prostate cancer recurrences after surgery: Individualized medicine or new standard in salvage treatment.
BACKGROUND
68Ga-PSMA-PET imaging is a novel promising diagnostic tool to locate early biochemical failure after radical prostatectomy (RP) in prostate cancer (PC) patients. Exact knowledge of the relapse location may result in changes of the therapy concept aside from changes to the TNM stage. To gain data for this approach, we evaluated PC patients receiving68Ga-PSMA-PET imaging before salvage radiotherapy (RT).


METHODS
In this study, 100 patients with biochemical failure after RP± prior RT who underwent68Ga-PSMA PET/CT or PET/MRI were evaluated undergoing salvage RT in our department. We analyzed TNM staging changes due to68Ga-PSMA-PET imaging and its influence on RT planning and treatment.


RESULTS
Uptake indicative for tumor recurrence in68Ga-PSMA-PET was found in 76% of the patients with biochemical recurrent PC. Median PSA level was 1.0 ng/mL (range 0.12-14.7 ng/mL). Of these, 80% showed no morphological correlate in the corresponding CT or MRI. A 43% of all patients experienced a change in TNM stage due to68Ga-PSMA-PET imaging. Patients had changes from Tx to rcT+ (28%), 12% from pN0 to rcN1, 1% from pN0/cM0 to rcM1a, and 8% from cM0 to rcM1b. Due to the additional knowledge of68Ga-PSMA-PET imaging, initial planned RT planning was adapted in 59% of all cases. An additional simultaneous integrated boost (SIB) to the prostate bed or lymph nodes was given to 32% and 63%, respectively. Ten patients received stereotactic body RT (SBRT) to single bone metastases.


CONCLUSIONS
68Ga-PSMA-PET imaging showed a high clinical impact on staging and RT management in patients with biochemically recurrent PC, even at low serum PSA levels. With 43% changes in staging and 59% in radiotherapy planning68Ga-PSMA-PET could lead to an indispensable tool in guiding radiation treatment in recurrent PC.
Department of Radiation Oncology, Technical University of Munich (TUM), Munich, Germany.|Zentrum für Stereotaxie und personalisierte Hochpräzisionsstrahlentherapie (StereotakTUM), Technische Universität München (TUM), Munich, Germany.
Gregor
http://orcid.org/0000-0002-5719-7567
G
Habl
Department of Radiation Oncology, Technical University of Munich (TUM), Munich, Germany.
Katharina
K
Sauter
Department of Radiation Oncology, Technical University of Munich (TUM), Munich, Germany.
Kilian
K
Schiller
Department of Radiation Oncology, Technical University of Munich (TUM), Munich, Germany.
Sabrina
S
Dewes
Department of Urology, Technical University Munich (TUM), Munich, Germany.
Tobias
T
Maurer
Department of Nuclear Medicine, Technical University Munich (TUM), Munich, Germany.|Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California.
Matthias
M
Eiber
Department of Radiation Oncology, Technical University of Munich (TUM), Munich, Germany.|Zentrum für Stereotaxie und personalisierte Hochpräzisionsstrahlentherapie (StereotakTUM), Technische Universität München (TUM), Munich, Germany.
Stephanie E
SE
Combs
D000368:Aged; D001669:Biochemical Phenomena; D001859:Bone Neoplasms / Q000737:chemistry / Q000473:pathology / Q000556:secondary; D005710:Gallium Radioisotopes / Q000494:pharmacology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D009367:Neoplasm Staging; D010347:Patient Care Planning; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D011468:Prostatectomy / Q000009:adverse effects* / Q000379:methods; D011471:Prostatic Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D019275:Radiopharmaceuticals / Q000494:pharmacology; D018714:Radiotherapy, Adjuvant / Q000379:methods; D012008:Recurrence; D015203:Reproducibility of Results
D005710:Gallium Radioisotopes; D019275:Radiopharmaceuticals
PSMA; individualized radiotherapy; prostate cancer; recurrence; restaging; salvage radiotherapy