Background: Peptide receptor radionuclide therapy (PRRT) is an effective treatment for neuroendocrine neoplasms (NENs); however, real-world data in Asia remain limited.
Methods: In this multicenter, nationwide study, we retrospectively analyzed 422 patients with unresectable or recurrent NENs who received 177Lu-DOTATATE-based PRRT at 33 institutions in Japan. Safety analyses were conducted in all enrolled patients and efficacy in 383 patients with complete covariates.
Results: The median age was 64 years. The most common primary sites were pancreas (n = 210, 54.8%) and hindgut (n = 81, 21.1%), with fewer midgut cases (n = 19, 5.0%). The tumor grades were G1 (13.3%), G2 (71.2%), G3 (14.6%), and neuroendocrine carcinoma (1.8%). The objective response rate (ORR) was 37.6%, favorable in pancreas (45.2%) and hindgut (40.7%). The median progression-free survival (PFS) was 21.4 months (95% confidence interval [CI], 19.7-22.8). Of 24 patients with hormonal symptoms, 18 (75%) showed marked improvement. Multivariate analysis revealed the following predictors: for ORR (odds ratio, 95% CI), pancreas (4.02, 2.18-7.78), hindgut (3.14, 1.53-6.69), Krenning score (KS) of 4 (2.96, 1.54-6.04), and liver metastasis ≤ 30 mm (1.64, 1.01-2.67); for PFS (hazard ratio, 95% CI), Ki-67 < 10% (0.46, 0.32-0.66), KS of 4 (0.65, 0.43-0.99), liver tumor burden < 50% (0.59, 0.39-0.89), liver tumor size ≤ 30 mm (0.49, 0.32-0.74), and combination with somatostatin analogs (0.64, 0.42-0.99). Grade ≥ 3 adverse events were infrequent, including hematologic (18%) and renal toxicities (< 1%).
Conclusions: 177Lu-DOTATATE demonstrated favorable efficacy and safety in Japanese patients, particularly for pancreatic and hindgut NENs, with symptomatic benefits in functional tumors.
Keywords: 177Lu-DOTATATE; Japanese patients; Multicenter study; Neuroendocrine neoplasm; PRRT.
© 2026. The Author(s), under exclusive licence to Japanese Society of Gastroenterology.