Survival benefits and efficacy of peptide receptor radionuclide therapy (PRRT) using Y-90/Lu-177 DOTA-TATE in pancreatic neuroendocrine tumor (pNET)

Objectives To evaluate the response to PRRT, using Y-90 or Lu-177 DOTA-TATE) and assess overall survival in patients with pNET.

Methods 107 patients (mean age 60 yrs) of progressive pNET were treated with 1-7 cycles of PRRT using Y-90/Lu-177 DOTA-TATE. Response assessment (using Ga-68 DOTA-NOC PET/CT) was done in 54 patients receiving more than 3 cycles of PRRT and followed up for > 3 months.

Results Mean/ Median duration of follow-up after first diagnosis (FD) was 107/58.5 months. 29/107 (27%) died. 26/107 (24%) had nonfunctional, 84/107 (76%) had functional pNET. Tumor localisation: head -31, body- 16, tail and cauda -41, total pancreas -4, body and tail -9 , head and body-. 11 patients had gastrinoma, 7 glucagonoma and 2 insulinoma. Metastases in liver was present in 99/107 (92.5%), lymph node 58/107 (54%) and in bone 38/107 (36.4%). The patients were pretreated with chemotherapy-44/107 (41%), surgery 52/107 (48.6%) and biotherapy (octreotide) 46/107 (43%). Objective response was seen in 52% of the patients, 39% had SD and 9% had PD. Median duration of survival from FD was 189 months. Median survival in patients with pNET in head (132 months) was less than that in body/cauda/tail (256 months). Mean survival in nonfunctional pNET was 148 months as compared to 341 months for functional pNET. Mean survival in patients with Ki 67 < 20% was 183 months vs 73 months for Ki 67 > 20%.

Conclusions PRRT is an effective therapy option for pNET. Patients with pNET in head of pancreas and high grade tumor (Ki67 > 20%) have the worst prognosis.