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
3353 - Results of the 3rd interim analysis of C-Patrol: A non-interventional study on olaparib in German routine clinical practice
Presenter: Jalid Sehouli
Session: Poster Display session 2
Resources:
Abstract
740 - A real-world analysis of the treatment of advanced ovarian cancer with PARPIs
Presenter: Alejandra Martinez de Pinillos
Session: Poster Display session 2
Resources:
Abstract
5867 - Incidence of tumour BRCA1/2 variants in relapsed, platinum-sensitive ovarian, fallopian tube and primary peritoneal cancer
Presenter: Robert Morgan
Session: Poster Display session 2
Resources:
Abstract
2966 - Frequency of mutations in 21 hereditary breast and ovarian cancer susceptibility genes among 882 high-risk individuals
Presenter: Jihong Liu
Session: Poster Display session 2
Resources:
Abstract
1687 - BRCA testing of 1,284 Brazilian patients for hereditary breast and ovarian cancer in a routine diagnostic setting
Presenter: Fernanda Milanezi
Session: Poster Display session 2
Resources:
Abstract
3162 - A multi-center integrative study on cancer predisposition genes in Chinese patients with epithelial ovarian carcinoma
Presenter: Changbin Zhu
Session: Poster Display session 2
Resources:
Abstract
5993 - Incidental Early Occult Ovarian Cancer after Risk-Reducing Salpingo-Oophorectomy in BRCA1/2 Mutation Carriers followed in a Community Public Hospital
Presenter: Begona Grana Suarez
Session: Poster Display session 2
Resources:
Abstract
5334 - Response to chemotherapy in ovarian cancer (OC) patients with or without prior breast cancer (BC), stratified by BRCA mutation (BRCAm) status
Presenter: Angela George
Session: Poster Display session 2
Resources:
Abstract
4565 - Advanced ovarian cancer: is residual disease after debulking surgery affected by genetics factors involved in angiogenesis and immunity pathways?
Presenter: Michele Bartoletti
Session: Poster Display session 2
Resources:
Abstract
3251 - Surrogate endpoint of progression-free (PFS) and overall survival (OS) for advanced ovarian cancer (AOC) patients (pts) treated with neo-adjuvant chemotherapy (NACT): Results of the CHIVA randomized phase II GINECO study
Presenter: Fabrice Lecuru
Session: Poster Display session 2
Resources:
Abstract