PT  - JOURNAL ARTICLE
AU  - Caner Civan
AU  - Stefan Kasper
AU  - Christoph Berliner
AU  - Pedro Fragoso-Costa
AU  - Viktor Grünwald
AU  - Michael Pogorzelski
AU  - Benedikt Michael Schaarschmidt
AU  - Stephan Lang
AU  - David Kersting
AU  - Michael Nader
AU  - Katharina Lückerath
AU  - Ken Herrmann
AU  - Wolfgang P. Fendler
AU  - Manuel Weber
TI  - PSMA-directed imaging and therapy of salivary gland tumors: a single-center retrospective study
AID  - 10.2967/jnumed.122.264342
DP  - 2022 Sep 01
TA  - Journal of Nuclear Medicine
PG  - jnumed.122.264342
4099  - http://jnm.snmjournals.org/content/early/2022/09/22/jnumed.122.264342.short
4100  - http://jnm.snmjournals.org/content/early/2022/09/22/jnumed.122.264342.full
AB  - We analyzed the diagnostic performance of PSMA-PET/CT as well as the dosimetry, efficacy, and safety of 177Lu-PSMA-radioligand therapy (PSMA-RLT) in salivary gland malignancies (SGM). Methods: We identified 28 SGM patients with PSMA-PET/CT from our database. CT and PSMA-PET/CT images were evaluated separately by three blinded readers in joint reading sessions. Pathological findings were grouped into six TNM regions (local tumor (T); regional lymph nodes (N)); metastases to non-regional lymph nodes, lung, bone, or other regions (M)) and lesion-based disease extent were classified as no disease (n = 1, 4%), unifocal (n = 2, 7%), oligometastatic (n = 9, 32%), multifocal (n = 3, 11%), and disseminated (n = 13, 47%). For each region, SUVmax of the lesion with highest uptake was measured and the visual PSMA expression score was evaluated on a per-patient basis using PROMISE criteria. The association between PSMA expression and a subset of clinical and histopathological markers was tested using Student’s t-test. Five patients underwent PSMA-RLT with intratherapeutic dosimetry. Response assessment was performed using RECIST 1.1, adverse events (AEs) were graded according to CTCAEv5.0 criteria. Results: Compared to CT, PSMA-PET/CT demonstrated additional metastatic lesions in 11/28 (39%) patients leading to upstaging of TNM and lesion-based disease extent in 3/28 (11%) and 6/28 (21%) patients, respectively. PSMA-PET/CT detected CT-occult local tumor, regional lymph nodes, non-regional lymph nodes and bone metastases in 1 (4%), 4 (14%), 2 (7%) and 4 (14%) patients respectively; no additional lesions were detected in the other pre-defined regions. PSMA expression level was higher than liver in 6 patients (25%). Significantly higher SUVmax was observed in male vs. female patients (15.8 vs. 8.5; P = 0.007) and in bone vs. lung lesions (14.2 vs 6.4; P = 0.006). PSMA-RLT was discontinued after one cycle in 3/5 patients due to insufficient radiation dose to the tumor. One male patient received 2 cycles with progression 3 months after PSMA-RLT initiation. Another male patient received 6 cycles and remained stable for more than 12 months after PSMA-RLT initiation. No CTCAEv5.0 Grade 3 or higher AEs occurred. Conclusion: In SGM, PSMA-PET/CT demonstrated superior detection rate and led to upstaging in about one third of patients when compared to CT. Male gender and presence of bone metastases were associated with significantly higher PSMA expression. PSMA-RLT was tolerated well and led to disease stabilization in two patients.