Performance of 68Ga-DOTA-SST PET/CT, octreoscan SPECT/CT and 18F-FDG PET/CT in the detection of culprit tumors causing osteomalacia: a meta-analysis

Objectives The objective of this study was to assess and compare the performance of Ga-68-DOTA-conjugated-somatostatin-receptor-targeting-peptides (Ga-68-DOTA-SST) PET/CT, octreoscan-SPECT/CT and F-18-FDG-PET/CT in the detection of tumor-induced osteomalacia (TIO). Methods Relevant studies reporting the performance Ga-68-DOTA-SST PET/CT, octreoscan-SPECT/CT and F-18-FDG-PET/CT in TIO were identified by searching PubMed, EMBASE, and Web of Science (last updated June 2019). Two authors independently extracted the numbers of true and false positives, and true and false negatives. The pooled estimates on a per-patient basis were calculated with 95% confidence interval (CI) obtained using a random-effects model. Results Fourteen studies comprising 346 patients were included in this meta-analysis. The meta-analysis provided the following results on a per-patient analysis. The pooled sensitivities of both Ga-68-DOTA-SST PET/CT (90%, 95% CI 82-95%) and octreoscan-SPECT/CT (83%, 95% CI 75-89%) were found to be significantly higher (P < 0.005) than that of F-18-FDG PET/CT (67%, 95% CI 53-80%). There was no statistically significant difference between the sensitivity of Ga-68-DOTA-SST PET/CT and octreoscan-SPECT/CT (P = 0.161). Owing to the low number of articles with true negative findings, the pooled specificities were not calculated. A total of 287 tumors were identified in 287 patients according to the data the included studies offered. The majority of the tumors were located in the lower extremities (59.6%, 171/287), followed by craniofacial regions (24.0%, 69/287), torso (9.4%%, 27/287), and upper extremities (6.9%, 20/287). Conclusion This meta-analysis demonstrates that somatostatin receptor-based imaging modalities outperformed F-18-FDG PET/CT in the detection of TIO, with Ga-68-DOTA-SST PET/CT performing slightly better than octreoscan-SPECT/CT.