Abstract 1564
Background
Intensity modulated radiation therapy (IMRT) is the standard of care for nasopharyngeal carcinoma (NPC). Part of the IMRT quality assurance process involves accurate target volume delineation, which is crucial for local control and survival. Current practice utilizes a uniform contouring method for clinical target volume (CTV) for all stages of NPC. Here, we conducted a single-arm phase 2 trial investigating the tumor control rates of reduced CTV margins and corresponding doses in low-risk, early-stage NPC.
Methods
Patients with biopsy-proven stage I-IIb (6th UICC/AJCC) NPC were enrolled. All patients were treated with IMRT alone. Two CTVs (CTV1 [high risk] and CTV2 [low risk]) were outlined; CTV1 was defined by grossly identified tumour (on MRI or CT) plus 5-mm margin (3-mm posteriorly); CTV2 was CTV1 plus 5-mm margin (3-mm posteriorly). 60 Gy and 50–54 Gy in 30 fractions were prescribed to CTV1 and CTV2, respectively. Primary end-point was locoregional recurrence free survival (LRRFS).
Results
From May 2001 to August 2006, 103 patients were recruited; all patients completed IMRT as planned (time duration 39-61 days). At a median follow-up of 12.6 years, five patients developed locoregional failures; of which one was in-field, and four were regional recurrence (two in-field and two marginal). 10-year LRRFS, distant metastasis free survival (DMFS), disease specific survival (DSS) and overall survival (OS) were 95.0% and 94.1%, 94.0% and 91.1%, respectively. The most common grade 1-2 late toxicities included subcutaneous fibrosis (79.6%), hearing loss (53.4%) and skin dystrophy (43.2%); grade 3 included subcutaneous fibrosis (2.9%) and hearing loss (2.9%); and no grade 4 late toxicity.
Conclusions
Reduced CTV margins and corresponding doses results in optimal long-term tumour control, with minimal late adverse events.
Clinical trial identification
NCT03839602.
Editorial acknowledgement
Legal entity responsible for the study
Chong Zhao.
Funding
National Natural Science Foundation of China [No. 81872469]; Science and Technology Project of Guangdong Province [No. 2014A020212433].
Disclosure
M.L.K. Chua: Honoraria (institution), Advisory / Consultancy: Janssen, Astellas, Varian, Ferring Singapore and AstraZeneca; Research grant / Funding (institution), Structured research agreement/Research funding - Ferring Singapore, GenomeDx Biosciences, Varian, MedLever.: Ferring Singapore, GenomeDx Biosciences, Varian, MedLever. All other authors have declared no conflicts of interest.
Resources from the same session
5007 - Functional systemic CD4 immunity is required for clinical responses to PD-L1/PD-1 blockade therapy
Presenter: Miren Zuazo
Session: Poster Display session 3
Resources:
Abstract
5760 - Landscape of PD-L1 expression status in Chinese solid tumor patients.
Presenter: Yi Zhong
Session: Poster Display session 3
Resources:
Abstract
3733 - Anti-cancer and immunomodulatory effects of cobimetinib in triple negative breast cancer
Presenter: Chun-Yu Liu
Session: Poster Display session 3
Resources:
Abstract
4426 - Differential expression of immunoregulatory molecules and highly-associated cancer genes may provide novel insights into strategic trial design for therapeutics
Presenter: Jacob Adashek
Session: Poster Display session 3
Resources:
Abstract
2752 - Insights into the Tumor Immune Microenvironment using Tissue Phenomics to Drive Cancer Immunotherapy
Presenter: Martin Groher
Session: Poster Display session 3
Resources:
Abstract
5713 - Immune competent somatic mosaic model of colorectal cancer
Presenter: Stefania Napolitano
Session: Poster Display session 3
Resources:
Abstract
1898 - Genomic correlates of response to anti-PDL1 Atezolizumab in non-small-cell lung cancer OAK and POPLAR trials
Presenter: Hari Singhal
Session: Poster Display session 3
Resources:
Abstract
3246 - Erdafitinib (erda) versus available therapies in advanced urothelial cancer: A matching adjusted indirect comparison
Presenter: Yohann Loriot
Session: Poster Display session 3
Resources:
Abstract
3311 - High level of activity of Nivolumab anti-PD-1 immunotherapy and favorable outcome in metastatic/refractory MSI-H non-colorectal cancer: Results of the MSI cohort from the French AcSé program
Presenter: Christophe Tournigand
Session: Poster Display session 3
Resources:
Abstract
2314 - TP53 and ATM Co-mutation Predicts Response to Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer
Presenter: Yu Chen
Session: Poster Display session 3
Resources:
Abstract