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

Abstract

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) ¹⁷⁷Lu-DOTATATE treatment.

Materials and methods: A retrospective single-center analysis was conducted on 26 patients who underwent ¹⁷⁷Lu-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 ¹⁷⁷Lu-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 ¹⁷⁷Lu-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 ¹⁷⁷Lu-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.