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
1988 - Molecular profiling reveals novel targetable biomarkers in neuroendocrine carcinoma of the uterine cervix
Presenter: Semir Vranic
Session: Poster Display session 2
Resources:
Abstract
2672 - Changes in clinico-pathological characteristics of vulvar cancer in Japan: increasing oldest-old, stage-shifting, and decreasing cohort-level survival
Presenter: Shin Nishio
Session: Poster Display session 2
Resources:
Abstract
4306 - Tumor Treating Fields (200 kHz) concomitant with weekly paclitaxel for platinum-resistant ovarian cancer: Phase 3 INNOVATE-3/ENGOT-ov50 study
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
5136 - Randomized, phase 1b/2 study of M6620 + avelumab + carboplatin vs standard care (sc) in patients (pts) with platinum-sensitive poly (ADP-ribose) polymerase inhibitor-(PARPi)-resistant ovarian cancer
Presenter: Susana Banerjee
Session: Poster Display session 2
Resources:
Abstract
2296 - An umbrella study of biomarker-driven targeted therapy in patients with platinum-resistant recurrent ovarian cancer: A Korean Gynecologic Oncology Group study (KGOG 3045), AMBITION
Presenter: Jung-Yun Lee
Session: Poster Display session 2
Resources:
Abstract
2732 - A phase 2 study of pembrolizumab in combination with doxorubicin in advanced, recurrent or metastatic endometrial cancer
Presenter: Ana Oaknin
Session: Poster Display session 2
Resources:
Abstract
4404 - ENGOT-EN9/LEAP-001: a phase 3, randomized, open-label study of pembrolizumab plus lenvatinib versus chemotherapy for first-line treatment of advanced or recurrent endometrial cancer
Presenter: Christian Marth
Session: Poster Display session 2
Resources:
Abstract
4564 - Phase 1/2 trial of tisotumab vedotin plus bevacizumab, pembrolizumab, or carboplatin in recurrent or metastatic cervical cancer (innovaTV 205/ENGOT-cx8)
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
4933 - Updated data of Epitopes-HPV02 trial and external validation of efficacy of DCF in prospective Epitopes-HPV01 study in advanced anal squamous cell carcinoma. Pooled analysis of 115 patients
Presenter: Stefano Kim
Session: Poster Display session 2
Resources:
Abstract
2301 - Pre-specified pilot analysis of a randomised pilot/phase II/III trial comparing standard dose vs dose-escalated concurrent chemoradiotherapy (CRT) in anal cancer (PLATO-ACT5)
Presenter: Alexandra Gilbert
Session: Poster Display session 2
Resources:
Abstract