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
3905 - Loss of CDX-2 expression is an independent poor prognostic biomarker in colorectal cancer
Presenter: Krittiya Korphaisarn
Session: Poster Display session 2
Resources:
Abstract
3963 - Robot-assisted natural orifice specimen extraction surgery for radical resection of colorectal cancer
Presenter: Zhengchuan Niu
Session: Poster Display session 2
Resources:
Abstract
3989 - Bevacizumab as adjuvant treatment for colon cancer: Updated results from the AVANT phase III Study by the GERCOR Group
Presenter: Thierry André
Session: Poster Display session 2
Resources:
Abstract
4741 - Real world data on adjuvant chemotherapy for high-risk stage II colorectal cancer – the role of tumor side
Presenter: Camila Araujo de Carvalho
Session: Poster Display session 2
Resources:
Abstract
4973 - Oncological Outcome and Safety of Bevacizumab (BV) Therapy in Patients with Occlusive Colon Cancer and Self-Expandable Metal Stents (SEMS)
Presenter: Vilma Pacheco-Barcia
Session: Poster Display session 2
Resources:
Abstract
2295 - Active chronic hepatitis B increases the risk of liver metastasis of colorectal cancer- a retrospective clinical study of 7187 consecutive cases of newly diagnosed colorectal cancer
Presenter: Lei Zhao
Session: Poster Display session 2
Resources:
Abstract
3845 - Comprehensive Evaluation of Recurrence Risk (CERR) Score for Colorectal Liver Metastases: Development and Validation
Presenter: Wei Ye
Session: Poster Display session 2
Resources:
Abstract
1976 - BRAF-mutated colorectal metastases: what is the benefit of liver surgery? Results from a cohort of 91 patients.
Presenter: Sahir Javed
Session: Poster Display session 2
Resources:
Abstract
2688 - The smallest colorectal liver metastasis size as a prognosis factor after laparoscopic liver resection
Presenter: Baptiste Cervantes
Session: Poster Display session 2
Resources:
Abstract
4961 - Validation of GAME score risk groups in resected colorectal cancer liver metastases and the prognostic relevance of KRAS, NRAS and BRAF mutation analysis
Presenter: Berta Martin-Cullell
Session: Poster Display session 2
Resources:
Abstract