First Clinical Experience with Gallium-68-OPS-202 PET for Imaging SCLC

Ziel/Aim In patients with somatostatin receptor (SSTR)-expressing small cell lung cancer (SCLC), PET imaging using the SSTR-antagonist satoreotide trizoxetan (OPS-202) could offer accurate tumor detection and screening for SSTR-antagonist radionuclide therapy. The aim of this study was to investigate tumor detection rates and uptake in Gallium-68-OPS-202 PET performed for (re-)staging of SCLC patients.

Methodik/Methods Twenty-seven patients with SCLC (24 before/under first line CTx/RCTx, 3 with recurrent disease) who underwent clinical whole-body Gallium-68-OPS-202 PET/CT were included. Mean administered activity was 135 MBq and mean uptake time was 59 min. For 20 patients, additional staging FDG PET/CT was available within 2 weeks before/after OPS PET. OPS- and/or FDG-positive lesions were reported in different anatomical categories (lungs, thoracic lymph nodes, distant metastases) and SUV_max of the hottest lesion in each region was determined.

Ergebnisse/Results Twenty-six of 27 patients were OPS-positive (96%). Primary tumor was detected in all positive patients (100%), thoracic lymph node metastases were detected in 23 patients (88%) and distant metastases in 14 patients (54%). Mean±SD SUV_max was 9.8±7.8 (primary), 9.4±8.3 (lymph nodes), and 11.8±9.6 (distant metastases), respectively. Thirteen patients demonstrated an OPS SUV_max>10. All patients with available FDG PET were OPS- and FDG-positive. In one patient a contralateral lymph node metastasis was detected only in OPS PET (cN3 vs. cN2), in one patient liver metastases were only detected in OPS PET, and in one patient lymph node metastases were only detected in FDG PET (cN0 vs. cN3). However, these differences did not lead to changes in treatment strategies. For primary tumors, mean FDG SUV_max was significantly higher than OPS SUV_max(15.4 vs 10.8, pmax>OPS SUV_max in lymph nodes and mean OPS SUV_max>FDG SUV_max in distant metastases) were not significant. Overall, the correlation between OPS and FDG uptake was low (Spearman’s rho 0.35).

Schlussfolgerungen/Conclusions Gallium-68-OPS-202 PET offers high diagnostic precision in SCLC patients and complementary information to FDG PET. High tumor uptake in half of the patients highlights the theranostic potential of Gallium-68-/Lutetium-177-OPS.

Publication History

Article published online:
30 March 2023