Detection level and pattern of positive lesions using PSMA PET/CT for staging prior to radiation therapy

Schmidt-Hegemann, Nina-Sophie; Fendler, Wolfgang Peter; Buchner, Alexander; Stief, Christian; Rogowski, Paul; Niyazi, Maximilian; Eze, Chukwuka; Li, Minglun; Bartenstein, Peter; Belka, Claus und Ganswindt, Ute (2017): Detection level and pattern of positive lesions using PSMA PET/CT for staging prior to radiation therapy. In: Radiation Oncology 12:176

Abstract

Background: To determine the potential role of Ga-68-PSMA positron emission tomography/computed tomography (PET/CT) in radiotherapy (RT) planning for prostate cancer (PCa). Methods: One hundred twenty-nine patients (pts) with Ga-68-PSMA PET/CT were retrospectively analysed. Potentially influencing factors (androgen deprivation therapy, amount of Ga-68-PSMA-HBED-CC, PSA doubling time <=/> 10 months, PSA before PET/CT, T-/N-category and Gleason score) were evaluated by logistic regression analysis. The detection rate of PSMA PET/CT was compared to contrast enhanced CT and its impact on RT management analysed. Results: One hundred twenty-nine patients (pts) (20 at initial diagnosis, 49 with PSA relapse and 60 with PSA persistence after radical prostatectomy) received PSMA PET/CT prior to RT. The majority of pts. (71.3%) had PET-positive findings (55.1% of pts. with PSA recurrence, 75% of pts. with PSA persistence and 100% of newly diagnosed pts). Median PSA before PET/CT in pts. with pathological findings (n = 92) was 1.90 ng/ml and without (n = 37) 0. 30 ng/ml. PSA level at time of PET/CT was the only factor associated with PET-positivity. In pts. with a PSA <= 0.2 ng/ml, the detection rate of any lesion was 33.3%, with a PSA of 0.21-0.5 ng/ml 41.2% and with a PSA of 0.51-1.0 ng/ml 69. 2%, respectively. Regarding the anatomic distribution of lesions, 42.2% and 14.7% of pts. with relapse or persistence had pelvic lymph node and distant metastases. In pts. at initial diagnosis the detection rate of pelvic lymph nodes and distant metastases was 20% and 10%. 68Ga-PSMA PET/CT had a high detection rate of PCa recurrence outside the prostatic fossa in pts. being considered for salvage RT (22.4% PET-positive pelvic lymph nodes and 4.1% distant metastases). Compared to CT, PSMA PET/CT had a significantly higher sensitivity in diagnosing rates of local recurrence/primary tumour (10.1% vs. 38%), lymph nodes (15.5% vs. 38.8%) and distant metastases (5.4% vs. 14.0%). This resulted in a modification of RT treatment in 56.6% of pts. Conclusions: The detection of PCa is strongly associated with PSA level at time of Ga-68-PSMA PET/CT. PSMA PET/CT differentiates between local, regional and distant metastatic disease with implications for disease management. PSMA PET/CT allows for tumour detection in post-prostatectomy pts. with PSA <= 0.5 ng/ml considered for salvage RT.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 1748-717X
• Sprache: Englisch