The therapeutic efficacy of 177Lu-DOTATATE/DOTATOC in advanced neuroendocrine tumors A meta-analysis

Background: Somatostatin analog therapies showed great potential for patients suffering advanced neuroendocrine tumors (NETs). This study was aimed to evaluate the therapeutic efficacy of Lu-177-DOTATATE/DOTATOC (Lu-177-octreotate/octreotide) peptide receptor radionuclide therapy (PRRT) in advanced or inoperable NETs patients. Methods: Pubmed, Web of Science, Embase and Cochrane Library were searched from 1950 to April 2019. Eligible studies should include randomized or nonrandomized controlled trials (RCTs)-based investigations of Lu-177-octreotate/octreotide PRRT for NETs. All these studies were assessed with Response Evaluation Criteria in Solid Tumors (RECIST), RECIST 1.1, Southwest Oncology Group (SWOG) criteria or World Health Organization (WHO) criteria. Disease response rates (DRRs) and disease control rates (DCRs) were calculated according to each response criteria group. DRRs were defined as the percentages of patients with complete response (CR) + partial response (PR), while DCRs represented the percentages of patients with CR+ PR+ stable disease (SD). The pooled proportions were calculated with either a fixed-effects model or a random-effects model depending on the test for heterogeneity. Results: A total of 22 studies (1758 patients) were included in this meta-analysis: 8 studies with 478 patients met RECIST criteria, 10 studies with 1127 patients met RECIST 1.1 criteria, 5 studies with 459 patients met SWOG criteria, and 1 study with 40 patients met WHO criteria, and among these articles 1 study met both RECIST and RECIST 1.1 criteria and 1 met both RECIST 1.1 and SWOG criteria. The pooled DRRs were 33.0% (95% CI: 25.0%-42.0%, I-2 = 65%), 35.0% (95% CI: 26.0%-45.0%, I-2 = 91%) and 25.0% (95% CI: 14.0%-36.0%, I-2 = 84%) according to RECIST, RECIST 1.1 and SWOG criteria, respectively. The pooled DCRs were 79.0% (95% CI: 75.0%-83.0%, I-2 = 97%), 83.0% (95% CI: 78.0%-88.0%, I-2 = 0) and 82.0% (95% CI: 75.0%-89.0%, I-2 = 91%), respectively. Conclusion: In advanced NETs patients, DRRs and DCRs were significantly elevated after initial treatment with Lu-177-DOTATATE PRRT, which shows that this treatment would be beneficial and promising for advanced or inoperable NETs patients.