Abstract 871P
Background
A 2011 randomized trial demonstrated significant improvement in overall survival in patients with stage 2 NPC with the use of upfront concurrent chemoradiotherapy (CCRT) compared to two-dimensional (2D) RT alone. However, it is unclear if this trial affected routine clinical practice and whether the benefit observed in the trial can be reproduced at population level in the era of intensity modulated radiotherapy (IMRT) techniques. This study aims to determine the impact of this trial on the adoption of upfront CCRT and mortality in stage 2 NPC.
Methods
All patients diagnosed with stage 2 NPC in Singapore from 2003-2017 were identified using the Singapore Cancer Registry. We compared the trends in adoption of upfront CCRT for those diagnosed in 2003-2011 versus 2012-2017. We also compared the 5 year relative survival trends for patients diagnosed from 2003-2011 versus 2012-2013. The significance of changes in trends were examined using interrupted time series (ITS) analysis. Differences in OS of the trial and this study cohort was analyzed with Cox regression.
Results
We identified 778 patients with stage 2 NPC. Median age was 51 years old. Most were male (73%) and Chinese (95%). The adoption rate of CC was 7% in 2003. The adoption rate of CC was increasing every three monthly prior to 2012 at 0.61% (95% confidence interval (CI) 0.34% - 0.89%, P < 0.001). There was no significant difference in the trends of adoption rates of CC between time periods 2003-2011 and 2012-2017. The proportion of CCRT in 2017 was 42%. The 5 year relative survival was 85% for NPC diagnosed in 2003. There was no significant difference in the 5 year relative survival trends between patients diagnosed in 2003-2011 and 2012-2013. The 5 year relative survival was 69% for NPC diagnosed in 2013. There was no significant difference in overall survival between CCRT and RT when adjusted for age, gender, race and nodal status in time periods 2003-2011 (HR:0.66, 95% CI 0.38 - 1.14) and 2012-2017 (HR: 1.10, 95% CI 0.25 - 4.79).
Conclusions
The publication of the landmark trial in 2011 did not have an impact on the adoption of upfront CCRT for stage 2 NPC. The survival benefit of CC in the landmark trial could not be reproduced in the real-world settings in the era of routine IMRT techniques.
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.