Single Center Outcomes from Parenchymal-sparing Resections and Microwave Ablations for Neuroendocrine Tumor Liver Metastases

Abstract Background : Surgical debulking of neuroendocrine tumor (NET) is used as a therapeutic approach for metastatic NETs in selected centers. Reported outcomes after parenchymal-sparing liver resections (PSR) in NET patients with high numbers of liver metastases are sparse. Methods : NET patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function was examined, as well as symptom response, complications, and progression free survival. Results : 1069 liver lesions (median=17) were debulked from 53 patients with a combination of PSR (45%) and ultrasound-guided microwave ablations (MWA) (55%). Post-operative transaminitis was proportional to the number of lesions debulked: Median POD1 AST was 681 IU/L for 1-15 lesions vs. 1396 IU/L for >15 lesions, p =0.01 (R 2 =0.271, p <0.001) and ALT was 596 IU/L vs 1149 IU/L, respectively, p =0.01 (R 2 =0.221, p <0.001). Thrombocytopenia occurred in 75% of patients and severity correlated with increasing number of lesions (median POD2 platelets 157 x 10 9 /L for 1-15 lesions vs. 109 x 10 9 /L for >15 lesions, p =0.04; R 2 =0.163, p =0.003). Synthetic liver function measured by postoperative INR (median POD1 INR 1.3 vs 1.4, p =0.21) and total bilirubin (median POD 2 TB 1.35 vs 0.95 mg/dL; p =0.67) did not differ according to number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3/4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to recurrence was 10.9 months. Conclusions : PSR with MWA for large numbers of NET liver metastases is safe and effective for symptom control and does not affect synthetic liver function. Transaminitis and thrombocytopenia are proportionate to the amount of liver lesions debulked.