Analysis of clinical factors associated with incomplete standard protocol 177Lu-DOTATATE treatment in neuroendocrine tumor patients

Purpose To investigate the clinical features of patients with neuroendocrine tumors (NETs) who could not complete the standard protocol (4 cycles of 7.4 GBq per 8 weeks) Lu-177-DOTATATE treatment. Materials and methods A retrospective single-center analysis was conducted on 26 patients who underwent Lu-177-DOTATATE treatment between December 2021 and August 2024. Therapeutic outcome was compared with clinical features, including location and number of metastatic lesions, interval from diagnosis to the first Lu-177-DOTATATE treatment, and laboratory data. Statistical analyses were performed to identify clinical features associated with dose reduction or treatment discontinuation. Results The clinical data of 24 patients with metastatic neuroendocrine tumors (NETs) were analyzed, of whom 16 patients completed the standard protocol Lu-177-DOTATATE treatment. The most common adverse events were hematologic toxicities. Eight patients did not complete the standard protocol treatment, primarily due to adverse events (6/8). Single variable logistic regression analysis revealed that the presence of somatostatin receptor scintigraphy (SRS) positive bone metastases (OR = 21.0, 95% CI 2.37-186, p = 0.006) and lower hemoglobin levels (OR = 0.479, 95% CI 0.255-0.900, p = 0.022) were significantly associated with incomplete treatment. Notably, 5/8 patients in the incomplete group had extensive bone metastases (> 20 lesions), including 4 with diffuse metastases. Other variables, including age, sex, white blood cell count, platelet count, eGFR, and other metastatic sites, showed no significant association with treatment completion. Conclusions In this study, the presence of SRS-positive bone metastases and low hemoglobin levels were significant factors associated with the inability to complete Lu-177-DOTATATE treatment for NET patients. Extensive bone metastases, such as diffuse metastasis or more than 20 bone metastases, may be particularly associated with the inability to administer standard protocol treatment.