Table 1.
Characteristics of included studies.
| Author | Country | Design | No. Patients (n) | Inclusion Criteria Per Study | Exclusion Criteria Per Study | Intervention Groups | Control Group |
|---|---|---|---|---|---|---|---|
| Watzka et al. [27] | DE | Retrospective | 204 | Patients with LM of NEN. | N/A | Radical LM resection (n = 38) | No resection at all (n = 110) |
| Partelli et al. [26] | IT | Retrospective | 166 | Patients with synchronous LM from sporadic pNET. | Patients with extra-abdominal disease as well as those with peritoneal carcinomatosis and those with an inherited syndrome. | Radical LM resection + primary resection (n = 18) | No resection at all (n = 75) (SSA; PRRT; chemotherapy; everolimus or sunitinib) |
| Citterio et al. [21] | IT | Retrospective | 139 | ≤20 mitoses/10 high power field (HPF) and Ki-67 labelling index ≤ 20% at either the primary or metastatic sites; Hormone-secreting status associated with a distinct clinical syndrome (functioning NETs); Performance status (PS) 0–1 at presentation, according to the ECOG § | N/A | LM resection (n = 36) (32 were after primary resection) | No resection at all (n = 103) (SSA n = 95, SSA + chemo n = 30, SSA + everolimus n = 14, TACE or RFA + systemic and/or surgical treatment * n = 25) |
| Du et al. [24] | CN | Retrospective | 130 | LM from NET. | N/A | Radical resection of primary tumour (n = 42) | No resection at all (n = 56) (TACE (16/18 also received an RFA) n = 18, systemic chemotherapy n = 9, SSA n = 12, no treatment n = 17) |
| LM + primary resection (R0) n = 26, LM resection (R0) n = 6 | |||||||
| Primary + LM resection n = 26, primary resection n = 42, LM resection n = 6 | Chemotherapy (n = 21) chemotherapy (fluorouracil and/or epirubicin and/or doxorubicin and/or etoposide and/or cisplatin, etc.) n = 9, SSA n = 12) | ||||||
| TACE (n = 18) (16 also received a RFA) | |||||||
| Bertani et al. [17] | IT | Retrospective | 121 | Patients with synchronous and unresectable pNET LM. | N/A | Resection of primary tumour (n = 62) (n = 59 also received PRRT) | No resection at all (n = 59) (PRRT n = 55, SSA n = 29) |
| Boyar et al. [18] | NO | Retrospective | 114 | Patients with (WHO 2010) grade 1 and grade 2 tumours. | N/A | Resection of primary tumour with curative intent (n = 46) | No resection at all (n = 51) (streptozotocin + 5-fluorouracil/doxorubicin; SSA; IFN; embolization; PRRT; M-tor inhibitor) |
| Chamberlain et al. [19] | US | Retrospective | 85 | Patients treated for hepatic NET metastases. | The absence of identifiable liver disease, pathologic review at MSKCC revealing a non-NET or high-grade NET, or a patient decision to seek care elsewhere. | Segmentectomy or enucleation n = 12, lobectomy n = 3, extended resection n = 19 ‡ | Chemotherapy (n = 18) (streptozocin+ 5-FU; streptozocin + doxorubicin; 5-FU + leucovorin or cisplatin + etoposide) |
| HAE, with polyvinyl alcohol particles (n = 33) | |||||||
| Musunuru et al. [25] | US | Retrospective | 48 | Patients with liver-only metastatic neuroendocrine tumours. | N/A | Anatomical liver resection n = 6, ablation n = 4, resection and ablation n = 3 | Chemotherapy (n = 17) (observation, octreotide, and/or systemic chemotherapy) |
| Embolization (n = 18) | |||||||
| Chen et al. [20] | US | Retrospective | 38 | Patients treated for hepatic NET metastases. | Patients with evidence of extrahepatic disease or unresected known primary tumour. | LM resection (n = 15) (12 were combined with primary resection) | No resection at all (n = 23) (chemoembolization n = 5, chemotherapy and radiation n = 6, chemotherapy only n = 3, radiation only n = 2, no therapy n = 7) |
| Dousset et al. [23] | FR | Retrospective | 34 | Patients with metastatic endocrine tumours with bilobar metastases. | N/A | Curative intent resection n = 12 Palliative intent n = 5 † |
Chemotherapy (n = 8) (streptozotocin + fluorouracil n = 4, chemoembolization n = 4) |
| LTx (n = 9) | |||||||
| Coppa et al. [22] | IT | Retrospective | 29 | LM from NET, confirmed histological diagnosis. | Non-carcinoid primary tumours, tumours with systemic venous drainage. | Hepatic resection with curative intent (n = 20) | LTx (n = 9) |
IFN: interferon, IT: Italy, NO: Norway, US: United States, FR: France, 5-FU: 5-fluoro-uracil, CN: China, DE: Germany, pNET: pancreatic neuroendocrine tumours, NET: neuroendocrine tumours, LM: liver metastases, LTx: liver transplantation, NEN: neuroendocrine neoplasms, N/A: not available, PRRT: peptide receptor radionuclide therapy, RFA: radiofrequency ablation, SSA: somatostatin analogues; TACE: transarterial chemoembolization; * these interventions were also received by patients in the LM resection group; † n = 4 received additional chemotherapy and n = 4 chemoembolization; ‡ 28/34 with a curative intent; § Eastern Cooperative Oncology Group; ¶ Memorial Sloan Kettering Cancer Center.