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OA12 - Profiling the Multidisciplinary Management of Stage III NSCLC (ID 144)
- Event: WCLC 2019
- Type: Oral Session
- Track: Treatment of Locoregional Disease - NSCLC
- Presentations: 1
- Now Available
OA12.01 - PCI for Radically Treated Non-Small Cell Lung Cancer: A Meta-Analysis Using Updated Individual Patient Data of Randomized Trials (Now Available) (ID 2624)
15:45 - 17:15 | Presenting Author(s): Willem Witlox
In localized non-small cell lung cancer (NSCLC), prophylactic cranial irradiation (PCI) reduced the incidence of brain metastases (BM) (relative risk 0.35), but without a demonstrated effect on overall survival (OS). This may be due to the small sample size in these individual randomized clinical trials (RCTs).
Therefore, we aimed to assess the impact of PCI on long term OS for radically treated stage III NSCLC patients compared to observation using updated individual patient data (IPD) from RCTs.Method
The main endpoint was OS and secondary endpoints were progression-free survival (PFS), BM-free survival (BMFS) and toxicity. All analyses were performed based on the intention-to-treat principle. The median follow-up was estimated using the inverse Kaplan-Meier method. The log-rank observed minus expected number of events and its variance were used to calculate individual and overall pooled hazard ratios (HRs) and 95% confidence intervals (95% CIs) with a fixed effects model. Heterogeneity was studied using the Cochrane test and I2. Survival curves and 5-year difference between arms were estimated using the Peto method. Interaction between prognostic factors (age, performance status, and histology) and treatment allocation were assessed using Cox proportional hazards models. Toxicities grade ≥ 3 were reported descriptively.Result
Data on four of the seven eligible trials (SWOG 8300, RTOG 0214, Guangzhou 2005 and NVALT-11) were available for this IPD meta-analysis. In total, 924 patients were analyzed of which 68% was male, median age was 61 years, 94% of the patients had a performance status ≤ 1 and 37% had squamous histology. The median follow-up was 8.1 years. All trials provided sufficient IPD for the three endpoints, except for the SWOG 8300 trial (OS only). This trial explained inter-trial heterogeneity. Because of the qualitative interaction with the other trials (p=0.0062) it was separately analyzed (N=254). Compared to observation, OS was significantly lower for PCI in the SWOG 8300 trial (HR 1.38, 95% CI [1.07 to 1.79] p=0.013, 5-year absolute difference -0.9%, 95% CI [-5.9 to 4.1]). However, for the other trials (N=670) no significant OS difference was observed (HR 0.90, 95% CI [0.76 to 1.07] p=0.228, 5-year absolute difference 1.8%, 95% CI [-5.2 to 8.8]). PFS (HR 0.78, 95% CI [0.65 to 0.92] p=0.004, 5-year absolute difference 4.8%, 95% CI [-1.2 to 10.8]) and BMFS (0.38, 95% CI [0.27 to 0.53] p<0.001, 5-year absolute difference 20.7%, 95% CI [12.2 to 29.2]) were significantly higher in the PCI arm. There was no interaction between prognostic factors and treatment allocation for OS. Toxicity data for the PCI arm was available in all trials except the SWOG 8300 trial. The total number of patients with at least one grade ≥3 toxicity (for the adverse events pre-specified in the protocol) in the PCI arm was 19/456, including 11/86 in the NVALT-11 trial. Toxicity for the observation arm was only available in the NVALT-11 trial, including 4/88 patients with at least one grade ≥3 toxicity.Conclusion
Although PFS and BM-free survival were improved for patients who received PCI, no significant PCI benefit for OS was observed.
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