Objective
Peptide receptor radionuclide therapy (PRRT) is an effective treatment option in patients with metastatic neuroendocrine tumors (NETs). Recently, salvage PRRT has been introduced for progressing NET patients. This systematic review and meta-analysis evaluated the therapeutic efficacy, survival, and toxicity of salvage PRRT in patients with progressive NETs.
Methods
A systematic (PubMed, Embase, Cochrane, and Scopus) were performed. To determine therapeutic efficacy, objective response rate (ORR), and disease control rate (DCR) were identified using radiologic response criteria. To determine survival, progression-free survival (PFS), and overall survival (OS) were verified. To determine toxicity, information was collected on serious (grades 3 or 4) hematologic and renal adverse events.
Results
Nine articles featuring 426 patients were included in this study. Salvage PRRT achieved pooled proportions of ORR in 17.1% [95% confidence interval (CI) 11.6–23.5] and DCR in 76.9% (95% CI 72.3–81.0) of patients. Salvage PRRT demonstrated pooled estimates of PFS of 14.1 months (95% CI 12.2–15.9) and OS of 26.8 months (95% CI 18.8–34.9). Pooled proportions of hematologic and renal toxicities were 10.8% (95% CI 5.9–16.8) and 0.7% (95% CI 0.2–1.8), respectively. A subgroup direct comparison study with initial PRRT revealed that salvage PRRT showed significantly lower therapeutic efficacy (ORR and DCR, all P < 0.001) and shorter PFS (P = 0.03) despite similar hematologic toxicity (P = 0.25) and renal toxicity (P = 0.45).
Conclusion
Salvage PRRT is effective in patients with progressive NETs, and toxicity appeared to be similar to initial PRRT which could be a feasible treatment option.
