177Lu-DOTATATE therapy in patients with neuroendocrine tumours: 5 years' experience from a tertiary cancer care centre in India

Purpose The choice of an appropriate treatment option in patients with inoperable or metastatic neuroendocrine tumours (NETs) is limited, and approximately 50 % of patients have advanced NET at diagnosis, and 65 % die within 5 years. Treatment with Lu-177-DOTATATE (Lu-177-[DOTA(0),Tyr(3)] octreotate) is a promising new option in the treatment of metastatic NETs. Methods Patients with metastatic NET who underwent Lu-177-DOTATATE during the period 2009 to 2013 were included in this retrospective study. Follow-up imaging studies including a Ga-68-DOTANOC PET/CT scan and a posttherapy Lu-177-DOTATATE scan were compared with baseline imaging to determine response to treatment. Progression-free survival (PFS) was calculated using the Kaplan-Meier method and Cox regression analysis was also done. Results Ten patients (25 %) had a minimal response, 13 (32.5 %) had a partial response and 9 (22.5 %) had stable disease. Progressive disease was seen in 8 patients (20 %), including 6 patients who died during or after the treatment period. The estimated mean PFS in those who received one or two cycles of Lu-177-DOTATATE was 8.3 months (95 % CI 6.2 to 10.3 months) compared to an estimated mean PFS of 45.6 months (95 % CI 40.9 to 50.2 months) in those who received more than two cycles of Lu-177-DOTATATE (log-rank Mantel-Cox X-2 = 8.01, p = 0.005). Conclusion Our study showed that treatment with Lu-177-DOTATATE should be considered in the management of NETs, considering the limited success of alternative treatment modalities. Treatment response and PFS is determined primarily by the dose delivered and best results are obtained when more than two cycles of Lu-177-DOTATATE are given, with careful monitoring for possible side effects.