Abstract 295P
Background
We aim at subdividing M1 stage to better predict survival of metastatic nasopharyngeal carcinoma (NPC) patients whose outcomes could vary greatly.
Methods
Patients with previously untreated metastatic NPC (training cohort) were recruited prospectively from 2007 to 2018 and were re-staged based on 8th edition of American Joint Committee on Cancer system. All patients had baseline plasma EBV DNA at diagnosis of metastasis. Characteristics of metastases (site, number and size of metastatic lesions) were confirmed by MRI and PET-CT. We used recursive partitioning analysis (RPA) incorporating baseline plasma EBV DNA and/or metastatic characteristics with internal validations to subdivide M1 stage. The two models were externally validated using an independent data set of 67 NPC patients who were non-metastatic at diagnosis but later developed distant metastases after radical treatment (validation cohort). Performance of survival prediction between the two models was compared with paired t-test under 1000 bootstrapping samples.
Results
The training cohort of 69 patients had a median follow-up of 40.8 months and 3-year overall survival (OS) of 36%. Model 1 incorporating pre-treatment plasma EBV DNA subdivided M1 stage into two groups: M1a (EBV DNA ≤2500 copies/ml; OS 74%) and M1b (EBV DNA >2500 copies/ml; OS 17%) (P< .001). Model 2 basing on metastatic site also yielded good subdivision (M1a: no coexisting liver and bone involvement; M1b: coexisting both liver and bone metastases) (P= .023). Multivariable analyses demonstrated only baseline plasma EBV DNA (>2500 copies/ml) (HR 4.7 (95% CI 1.9-11.5); P= .001) and metastatic site (coexisting liver and bone metastasis) (HR 2.2 (1.0-4.7); P= .046) were prognostic of OS. Model 1 demonstrated better model fit in predicting OS (Model 1: mean AIC 246.9 (95% CI 187.8-303.6) vs Model 2: mean AIC 257.7 (200.6-313.2); P< .001). Model 1 also performed better prediction agreement in the validation cohort (Model 1: mean C-index: 0.59 (95% CI 0.53-0.67) vs. Model 2: mean C-index: 0.57 (0.51-0.63); P< .001).
Conclusions
A novel RPA-based M1 stage set incorporating baseline plasma EBV DNA had a significantly better survival prediction, providing important values on prognosis and treatment decision making.
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
284P - Differences in disease characteristics and survival outcomes of follicular lymphoma in young adults and older population: An institutional analysis
Presenter: Shina Goyal
Session: Poster display session
Resources:
Abstract
285TiP - Phase II, open-label study of pembrolizumab in children and young adults with newly diagnosed classical Hodgkin lymphoma (cHL) with slow early response (SER) to frontline chemotherapy: KEYNOTE-667
Presenter: Christine Mauz-koerholz
Session: Poster display session
Resources:
Abstract
294P - Validation of the 8th edition of AJCC/UICC staging system for nasopharyngeal carcinoma: Results from a non-endemic cohort with long-term follow-up
Presenter: Li-rong Wu
Session: Poster display session
Resources:
Abstract
296P - Nasopharyngeal carcinoma: A retrospective review of outcome in a single institution
Presenter: Wan Ping Ch' ng
Session: Poster display session
Resources:
Abstract
297P - Global longitudinal assessment of treatment outcomes in nasopharyngeal carcinoma (GLANCE-NPC) study
Presenter: Myung-Ju Ahn
Session: Poster display session
Resources:
Abstract
298P - Long-term complication and outcomes after induction chemotherapy with TPF followed by chemoradiotherapy for nasopharyngeal cancer
Presenter: Sang-Hee Cho
Session: Poster display session
Resources:
Abstract
299P - Weekly versus triweekly concurrent chemoradiation for nasopharyngeal cancer
Presenter: Sudibio Sudibio
Session: Poster display session
Resources:
Abstract
300P - Endoscopic nasopharyngectomy for localized stage I nasopharyngeal carcinoma
Presenter: Ming-Yuan Chen
Session: Poster display session
Resources:
Abstract
301P - Oncological outcome following 3 Drug NACT for Bucco-Alveolar carcinoma with Supra-notch ITF extension
Presenter: Karan Gupta
Session: Poster display session
Resources:
Abstract
303P - Segmental mandibulectomy without reconstruction
Presenter: Yohei Morishita
Session: Poster display session
Resources:
Abstract