Abstract 1180P
Background
To evaluate toxicity and interim efficacy of 177Lu-DOTATATE treatment (PPRT) in patients with progressive well differentiated GEPNETs.
Methods
We prospectively evaluated GEPNET patients treated at our Institution from April 2019 to April 2020. PRRT treatment was given as 4 separate infusions, 7.4 GBq each. To evaluate the interim response, CT or MRI were performed after the second PRRT administration. Side effects were assessed applying CTCAEv5.0 meanwhile RECIST 1.1 were applied to evaluate interim response.
Results
We evaluated 55 patients (21 males, 34 females; mean age 62.5, range 38-84) diagnosed as G1 (25, 44.6 %) or G2 (30, 53.6%) GEPNETs. The primary tumor was located in ileum (60%), pancreas (32.7%) and other sites (7.3%). PRRT was administered as 5th/6th-line in 25 cases (45.4%) 3rd/4th-line in 20 (36.4%) and 2nd-line therapy in 10 (18.2%). 48 patients (87.3%) were treated with 2, 37 (67.3%) with 3 and 22 (44.6%) completed the 4 administrations. PRRT was suspended in 8 patients (14.5%), previously treated with 2 (4 cases), 3 (3 cases) and 5 (1 case) systemic lines, due to toxicity (4 cases, 50%), radiological (2, 25%) and clinical progression (2, 25%). The lasting 2 cases consisted of intestinal occlusion and progression of neoplastic ascites that needed medical intervention. The toxicity that caused PRRT interruption were: 2 G2 persistent thrombocytopenia, 1 G4 hyperbilirubinemia and 1 G4 renal failure. The lasting 2 cases were known to have G2 hyperbilirubinemia and G2 renal failure before PRRT. In the remaining 51 patients, we observed hematological toxicities G1-G2 in 14 and G3 in 1 patient. G1 renal toxicity was shown in 1 patient and G3 in another one. 2 patients experienced G1 hepatic toxicity. Data from 34 available interim CT/MRI scan showed stable disease in 88.2%, 2 progression and 2 partial responses (5.9%).
Conclusions
In our real-life experience, PRRT is a safe treatment option even in patient previously treated with numerous therapeutic lines. PRRT is effective in early disease control, reaching stability in almost 90% of interim evaluations. However, effectiveness and safety could be improved if PRRT is early performed after disease progression. Further clinical studies are needed to confirm this hypothesis.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.