Abstract 3253
Background
Peptide receptor radionuclide therapy (PRRT) with 177Lutetium (177Lu) -DOTATATE is effective treatment for neuroendocrine tumors (NETs). Dosimetry assessment can be used to maximize the tumour dose, while keeping the dose delivered to critical organs to acceptable levels. The association between tumour absorbed dosimetry (TAD) and progression-free (PFS) and overall survival (OS) is not well understood.
Methods
Single institution retrospective analysis of patients with metastatic NET whom underwent up to 4 cycles of 7.45GBq 177Lu octreotate PRRT. Intra-therapeutic tumour dosimetry was performed with non-gated single photon emission computed tomography (SPECT) to quantify activity at 5 time points after administration of 177 Lu during cycle 1. TAD per injected activity (A0) and estimated total TAD (multiplied by total administered activity of 177Lu) was correlated with OS and PFS using the Kaplan–Meier method and Cox proportional-hazards model.
Results
79 patients were included, primary site: gastroenteric (48%), pancreatic (39%), bronchial (9%), other (4%), ECOG Performance status (PS) 0/1 (94%), Grade: G1 (47%), G2 (42%), G3 (11%), Ki-67≤20% (89%), concurrent chemotherapy use (29%). Mean TAD/A0 was 9(7-11) Gy/GBq. Progressive disease (54%) and death (29%) was seen. Median follow-up of 35 months. Median PFS was 32 [26-38] months. PFS was shorter with increasing ECOG PS (P = 0.02), tumour grade (P < 0.01), Ki-67 (P = 0.01), concurrent chemo-radionuclide therapy (P = 0.02) and reduced TAD (P = 0.036) but not primary site of origin (P = 0.66). A higher TAD led to an improved median PFS in pancreatic (P < 0.01) versus gastroenteric (P = 0.56) NETs. In a multivariate model incorporating ECOG PS, Ki-67 and chemotherapy use, total TAD remained significantly associated with PFS. The mean OS was 40 [36-44] months. OS was shorter with increasing tumour grade (P = 0.05), Ki-67 (P = 0.036) and reduced TAD (P = 0.039).
Conclusions
TAD was independently associated with OS and PFS validating dosimetry assessment in NET patients undergoing PRRT. Prospective refinement of the association on larger, more homogenous cohorts of NET patients is needed.
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.
Resources from the same session
3278 - Immune-Related Gene Expression Profiling after Neoadjuvant Chemotherapy (NACT) of Ovarian High-Grade Serous Carcinoma
Presenter: Luis Manso
Session: Poster Display session 2
Resources:
Abstract
4906 - Tumor-infiltrating lymphocytes (TILs) in patients with epithelial ovarian cancer undergoing neoadjuvant chemotherapy: A restrospective study
Presenter: Sara Giovannoni
Session: Poster Display session 2
Resources:
Abstract
3919 - Prognostic significance of elements of the adaptive immunity in the microenvironment of epithelial ovarian cancer.
Presenter: Periklis Foukas
Session: Poster Display session 2
Resources:
Abstract
5139 - Neutrophil-to-lymphocyte ratio predicts platinum sensitivity in epithelial ovarian cancer patients: a MITO24 retrospective study
Presenter: Alberto Farolfi
Session: Poster Display session 2
Resources:
Abstract
4212 - The prognostic impact of monocyte to lymphocyte ratio (MLR) in advanced epithelial ovarian cancer (EOC)
Presenter: Marc Cucurull Salamero
Session: Poster Display session 2
Resources:
Abstract
5123 - TP53 Hotspot mutations as immunoreactive neoantigens define a signature with differential survival outcomes in advanced ovarian cancer
Presenter: Marica Garziera
Session: Poster Display session 2
Resources:
Abstract
3795 - Use of bevacizumab (Bev) in real life for first-line (fl) treatment of ovarian cancer (OC)/ The GINECO ENCOURAGE cohort of 500 French patients
Presenter: Dominique Berton-Rigaud
Session: Poster Display session 2
Resources:
Abstract
2359 - Phase II study: Letrozole maintenance therapy after first line chemotherapy in patients with advanced serous and endometrioid ovarian cancer
Presenter: Alexandra Tyulyandina
Session: Poster Display session 2
Resources:
Abstract
3619 - Baseline IPI (Immune Prognostic Index) predicts survival in patients with advanced cervical cancer treated with immune checkpoint inhibitors (ICI).
Presenter: Felix Blanc-Durand
Session: Poster Display session 2
Resources:
Abstract
3474 - Preselecting tumor-infiltrating lymphocyte subsets to implement adoptive inmmunotherapy in ovarian cancer
Presenter: Diego Salas-Benito
Session: Poster Display session 2
Resources:
Abstract