Somatostatin-based radiopeptide therapy with [177Lu-DOTA]-TOC versus [90Y-DOTA]-TOC in neuroendocrine tumours

Somatostatin-based radiopeptide treatment is generally performed using the beta-emitting radionuclides Y-90 or Lu-177. The present study aimed at comparing benefits and harms of both therapeutic approaches. In a comparative cohort study, patients with advanced neuroendocrine tumours underwent repeated cycles of [Y-90-DOTA]-TOC or [Lu-177-DOTA]-TOC until progression of disease or permanent adverse events. Multivariable Cox regression and competing risks regression were employed to examine predictors of survival and adverse events for both treatment groups. Overall, 910 patients underwent 1,804 cycles of [Y-90-DOTA]-TOC and 141 patients underwent 259 cycles of [Lu-177-DOTA]-TOC. The median survival after [Lu-177-DOTA]-TOC and after [Y-90-DOTA]-TOC was comparable (45.5 months versus 35.9 months, hazard ratio 0.91, 95 % confidence interval 0.63-1.30, p = 0.49). Subgroup analyses revealed a significantly longer survival for [Lu-177-DOTA]-TOC over [Y-90-DOTA]-TOC in patients with low tumour uptake, solitary lesions and extra-hepatic lesions. The rate of severe transient haematotoxicities was lower after [Lu-177-DOTA]-TOC treatment (1.4 vs 10.1 %, p = 0.001), while the rate of severe permanent renal toxicities was similar in both treatment groups (9.2 vs 7.8 %, p = 0.32). The present results revealed no difference in median overall survival after [Lu-177-DOTA]-TOC and [Y-90-DOTA]-TOC. Furthermore, [Lu-177-DOTA]-TOC was less haematotoxic than [Y-90-DOTA]-TOC.