Selective internal radiation therapy for neuroendocrine liver metastases: efficacy, safety and prognostic factors. A retrospective single institution study.

BACKGROUND AND STUDY AIMS: Selective internal radiation therapy (SIRT) has shown good results in unresectable liver metastases from neuroendocrine neoplasms (NELM) with a high disease control rate (DCR) reported. The aims of the study is to assess retrospectively the efficacy and safety of 10y of SIRT for NELM.

PATIENTS AND

METHODS

Primary endpoint was objective response rate (ORR) and DCR by RECIST 1.1 at 2, 4 and 12 months (m). Secondary endpoints were overall survival (OS), liver progressionfree survival (liver-PFS), clinical response (NEN-related symptoms improvement) and safety.

RESULTS

50 consecutive patients with NELM who got SIRT from 2011 to 2021 in one center. The two major NEN primary sites were pancreas (46%) and small intestine (36%). Histological NEN grades were 10%, 46% and 44% for grades 1, 2 and 3 respectively. ORR and DCR were 16% and 80% at 2m, 22% and 92% at 4m and 32% and 82% at 12m. Survival rates at 1 and 2 y were 76% and 72% respectively. Prognostic factors for OS and liver-PFS were NEN histological grade (3 vs 1+2) (hazard ratio (HR) for OS: 4.33 [1.8-10.6], for liver-PFS: 3.91 [1.3-11.4]), and early (2m) DCR (HR for OS: 0.14 [0.1-0.4], for liver-PFS: 0.016 [0.003-0.08]). Clinical response occurred in 7 of the 10 symptomatic patients. One patient died from radioembolization-induced liver disease.

CONCLUSION

SIRT showed efficacy in NELM pts, with a high DCR and an good safety profile. G1-2 grade and early DCR were associated with a better OS and liver-PFS.