Peptide receptor radionuclide therapy (PRRT) is safe and effective for patients with grade 3 (G3) neuroendocrine neoplasms (NENs), according to research presented at the Society of Nuclear Medicine and Molecular Imaging's (SNMMI) annual meeting.
In the study, 69 patients with grade 3 (G3) neuroendocrine neoplasms (NENs) with a Ki-67 proliferation index of >20%, received PRRT with 177lutetium (177Lu) and/or 90Y-labelled DOTATATE or DOTATOC.
Forty-six patients had pancreatic NENs, 11 had unknown primary cancer, six had midgut NENs, three had gastric NENs, and three had rectal NENs.
PRRT was applied as first-line treatment in eight patients (11.6%), as second-line treatment in 25 patients (36.2%), and as third-line therapy in 28 patients (40.6%). The time span (mean ± SD) between biopsy for the assessment of Ki-67 and the first treatment cycle was 27.1 ± 36.8 months. Median follow-up was 94.3 months.
Median progression-free survival (PFS) and overall survival (OS) were 9.6 months and 19.9 months, respectively. For G3 NEN with Ki-67 ≤55% (n=53), median PFS was 11 months and median OS 22 months. Patients with Ki-67 >55% (n=11), had median PFS and OS of four months and seven months, respectively.
PRRT was well-tolerated, with no hepatotoxicity or grade 3/4 haematotoxicity, and no significant decline in renal function.