Malignancy Detection Rates of [68Ga]Ga-SSO120 PET/CT in Patients with Small Cell Lung Cancer and Large Cell Neuroendocrine Lung Cancer

The primary aim of this study was to investigate the malignancy detection rate of [68Ga]Ga-SSO120 ([68Ga]Ga-satoreotide trizoxetan) PET/CT in patients with small cell lung cancer (SCLC) and large cell neuroendocrine lung cancer (LCNEC). Secondary aims included investigations of lesion-based detection rates and quantification. Methods: In this prospective, phase 2, cross-sectional imaging trial, 21 [68Ga]Ga-SSO120 PET/CTs were performed for 19 patients. Overall detection rates, lesion-based detection rates, and number of identified lesions were compared between [68Ga]Ga-SSO120 PET and CT. The [68Ga]Ga-SSO120 SUVmax, SUVpeak, SUVmean, and tumor-to-liver ratios in malignant lesions and selected normal tissue were quantified. Results: Nineteen patients (16 with SCLC, 2 with LCNEC, and 1 with combined SCLC/LCNEC) were scanned during palliation chemotherapy (n = 11) or surveillance (n = 8). [68Ga]Ga-SSO120-detectable lesions were identified in 18 patients (95%). Sensitivity in the lungs, regional lymph nodes, and extrathoracic regions was 82%, 83%, and 93%, respectively. [68Ga]Ga-SSO120 PET detected significantly fewer lesions than did CT (P = 0.037), particularly small lung lesions, regional lymph nodes, and liver lesions. In contrast, [68Ga]Ga-SSO120 PET identified 10 additional metastases in 5 patients (bone, 7; cerebellum, 1; subcutaneous, 2). SUVmax (median, 7.4; range, 4.6-26.4) was not significantly associated with time since diagnosis, time since last chemotherapy, number of treatment cycles, or current progression. Conclusion: [68Ga]Ga-SSO120 PET/CT successfully visualized SCLC and LCNEC lesions during and after chemotherapy. Therapeutic studies with [177Lu]Lu-SSO110 ([177Lu]Lu-satoreotide tetraxetan), the theranostic companion of [68Ga]Ga-SSO120, PET are warranted.