Tumor response and clinical benefit in neuroendocrine tumors after 7.4 GBq (90)Y-DOTATOC.

TLDR

The study aimed to assess tumor response and clinical benefit of high‑dose (90)Y‑DOTATOC in patients with progressive neuroendocrine gastroenteropancreatic and bronchial tumors. Patients received four intravenous injections of 7.4 GBq/m² (90)Y‑DOTATOC every six weeks, with clinical benefit evaluated after each cycle using NCI‑CTC grading and tumor response assessed by WHO criteria. High‑dose (90)Y‑DOTATOC produced a 23% objective response rate (38% in endocrine pancreatic tumors), 63% overall clinical benefit, and was well tolerated, with most responses durable over a median 6‑month follow‑up and manageable grade 3/4 toxicities.

Abstract

The aim of this prospective phase II study was to evaluate the tumor response of neuroendocrine tumors to high-dose targeted irradiation with 7.4 GBq/m(2) of the radiolabeled somatostatin analog (90)Y-1,4,7,10-tetra-azacyclododecan-4,7,10-tricarboxy-methyl-1-yl-acetyl-D-Phe-Tyr(3)-octreotide (DOTATOC). In addition, we investigated the clinical benefit of (90)Y-DOTATOC regarding the malignant carcinoid syndrome and tumor-associated pain.Thirty-nine patients (mean age, 55 y) with progressive neuroendocrine gastroenteropancreatic and bronchial tumors were included. The treatment consisted of 4 equal intravenous injections of a total of 7.4 GBq/m(2) (90)Y-DOTATOC, administered at intervals of 6 wk. After each treatment cycle, a standardized clinical benefit assessment using the National Cancer Institute grading criteria (NCI-CTC) was performed.The objective response rate according to World Health Organization (WHO) criteria was 23%. For endocrine pancreatic tumors (13 patients), the objective response rate was 38%. Complete remissions were found in 5% (2/39), partial remissions in 18% (7/39), stable disease in 69% (27/39), and progressive disease in 8% (3/39). A significant reduction of clinical symptoms could be found in 83% of patients with diarrhea, in 46% of patients with flush, in 63% of patients with wheezing, and in 75% of patients with pellagra. The overall clinical benefit was 63%. All responses (both clinical benefit and WHO response) were ongoing for the duration of follow-up (median, 6 mo; range, 2-12 mo). Side effects were grade 3 or 4 (NCI-CTC) lymphocytopenia in 23%, grade 3 anemia in 3%, and grade 2 renal insufficiency in 3%.High-dose targeted radiotherapy with 7.4 GBq/m(2) (90)Y-DOTATOC is a well-tolerated treatment for neuroendocrine tumors, with remarkable clinical benefit and objective response.