DOTATATE PET CT tumor volume as a predictor of surgical outcome in patients with metastatic gastroenteropancreatic neuroendocrine tumors

<h2>Abstract</h2><h3>Background</h3> Surgical debulking for metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is associated with increased progression-free survival (PFS) and overall survival (OS) in retrospective studies. It remains unclear, however, which patients benefit most from surgery. DOTATATE PET/CT tumor volume (TV) in metastatic GEP-NETs has been shown to correlate with PFS and OS. Herein, we investigate how TV impacts outcomes in patients undergoing surgical debulking for GEP-NETs. <h3>Methods</h3> A retrospective chart review was conducted of patients with pancreatic and small bowel NET (PNET/SBNET) who underwent surgical debulking at our institution from 2019 to 2022. All patients had an estimated liver debulking threshold of > 90 % and only patients with preoperative ⁶⁸Ga or ⁶⁴Cu-DOTATATE PET/CT were included. TV was obtained using the MIM Encore workstation. <h3>Results</h3> 71 patients with metastatic GEP-NETs (35 % PNET and 65 % SBNET) underwent liver debulking with 19 synchronous primary tumor resections. 42 patients had symptomatic disease. Patients were divided into 4 TV quartiles, ranging from 8.46 to 2000 mL. On cox proportional hazards modeling, tumor volume stratified by quartiles was not significantly associated with longer PFS (p = 0.250) over a median follow-up of 13 months (7−23). However, there was an increased risk for Clavien-Dindo Grade III and IV complications with higher TV quartiles (p = 0.008). SBNETs with carcinoid syndrome (p = 0.047) and those with more lesions debulked (p = 0.025) were more likely to have improvement in postoperative symptoms. <h3>Conclusion</h3> Patients with larger tumor burden on preoperative DOTATATE PET/CT should not be excluded from surgical intervention but may need to be counseled on higher risks of operative complications.