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TU_41_3006 - Hazard Ratio or Restricted Mean Survival Time for Quantifying the Effect of Adding Induction Chemotherapy for Locally Advanced Nasopharyngeal Carcinoma Treated with Concurrent Chemoradiotherapy Alone in Randomized Trials.

Tuesday, October 23
1:00 PM - 2:30 PM
Location: Innovation Hub, Exhibit Hall 3

Hazard Ratio or Restricted Mean Survival Time for Quantifying the Effect of Adding Induction Chemotherapy for Locally Advanced Nasopharyngeal Carcinoma Treated with Concurrent Chemoradiotherapy Alone in Randomized Trials.
Y. Y. Soon1, Z. Chen2, T. H. Tan3, T. Cheo3, J. Tey1, I. W. Tham1, and B. C. Tai2; 1National University Hospital, Singapore, Singapore, Singapore, 2National University of Singapore, Singapore, Singapore, 3National University Cancer Institute, Singapore, Singapore, Singapore

Purpose/Objective(s): To compare the effect of adding induction chemotherapy (IC) on progression-free (PFS) and overall survival (OS), measured by the hazard ratio (HR) and ratio of restricted mean survival time (RMST) in locally advanced treated with concurrent chemo-radiotherapy (CCRT) alone in randomized trials (RCTs).

Materials/Methods: We searched various biomedical databases for RCTs comparing IC plus CCRT versus CCRT alone. We reconstructed individual patient data for PFS and OS outcomes for each trial from the reported survival curves. The effect of IC was estimated using the HR and RMST at 2 years (HR2, RMST2), 3 years (HR3, RMST3) and the last observed time (HRLAST, RMSTLAST). The assumption of proportional hazards was evaluated using the Grambsch-Therneau test. A fixed effect meta-analysis was conducted to summarise the HR and RMST estimates at the prespecified time points. The respective estimates were compared using the Bland-Altman plots

Results: Six RCTs including 1415 patients were analysed. For both outcomes, there was no evidence of nonproportionality of hazards in the individual trials. For PFS, the respective estimates were: HR2 = 0.60and RMST2 = 0.63; HR3 = 0.65 and RMST3 = 0.66, HRLAST = 0.71 and RMSTLAST = 0.70. For OS, the respective estimates were: HR2 = 0.74 and RMST2 = 0.71; HR3 = 0.73 and RMST3 = 0.75; HRLAST = 0.77 and RMSTLAST = 0.73. The mean difference in estimates (RMST minus HR) for PFS were -0.03, -0.02 and -0.01 at 2-year, 3- year and the last observed time respectively. Similarly for OS, there difference were -0.004, -0.07 and -0.02 at 2-year, 3-year and the last observed time respectively.

Conclusion: Restricted mean survival time is a valid and useful alternative to hazard ratio in quantifying the effects of induction chemotherapy in randomized trials comparing induction chemotherapy plus concurrent chemo-radiotherapy versus chemo-radiotherapy alone for locally advanced nasopharyngeal carcinoma.

Author Disclosure: Y. Soon: None. T. Tan: None. I.W. Tham: None.

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TU_41_3006 - Hazard Ratio or Restricted Mean Survival Time for Quantifying the Effect of Adding Induction Chemotherapy for Locally Advanced Nasopharyngeal Carcinoma Treated with Concurrent Chemoradiotherapy Alone in Randomized Trials.



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