Key points are not available for this paper at this time.
Synthetic somatostatin analogs have been posed as a potential source of error in somatostatin receptor imaging through interference with tumor detection; however, experimental models and clinical studies have shown a complex mechanism of the effect of octreotide on tumors. The aim of this study was to assess whether 68Ga-DOTATATE uptake before treatment with long-acting somatostatin analogs differs from that after treatment. Methods: Thirty patients (15 men; age mean ± SD, 64.6 ± 13.4 y) who had intermediately differentiated to well-differentiated neuroendocrine tumors and who underwent 68Ga-DOTATATE PET/CT scanning before and after receiving long-acting repeatable octreotide (Sandostatin LAR) were included in the study. The SUVmax and SUVmean of healthy target organs, residual primary tumor, and up to 5 lesions with the highest SUVmax in each organ were compared before and after octreotide treatment. Results: The mean time interval between the 2 68Ga-DOTATATE studies was 9.6 ± 7.2 mo, and the mean time gap between the last Sandostatin LAR injection and the second 68Ga-DOTATATE study was 25.1 ± 14.8 d. The pretreatment mean SUVmax and SUVmean were both significantly higher in the thyroid, liver, and spleen (P P > 0.05). Conclusion: Long-acting octreotide treatment diminished 68Ga-DOTATATE uptake in the liver, spleen, and thyroid but did not compromise tracer uptake in residual primary tumor and metastatic lesions. These findings have a direct impact on the interpretation of 68Ga-DOTATATE PET/CT scans.
Ayati et al. (Thu,) studied this question.