1. Simulation Modeling of Cancer Clinical Trials: Application to Omitting Radiotherapy in Low-risk Breast Cancer
- Author
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Judith-Anne W. Chapman, Jeanne S. Mandelblatt, Jinani Jayasekera, Robert Gray, E. Shelley Hwang, Julia White, Timothy J. Whelan, Willi Sauerbrei, Juhee Song, Thomas B. Julian, Yisheng Li, Anthony Fyles, Judith O. Hopkins, Clyde B. Schechter, Stewart J. Anderson, Reshma Jagsi, Eric J. Feuer, Natasha K. Stout, Joseph A. Sparano, George Luta, Donald A. Berry, Xuelin Huang, and Richard C. Zellars
- Subjects
Oncology ,Cancer Research ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Proportional hazards model ,medicine.medical_treatment ,Lumpectomy ,Hazard ratio ,medicine.disease ,Confidence interval ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Randomized controlled trial ,law ,030220 oncology & carcinogenesis ,Internal medicine ,medicine ,Clinical endpoint ,030212 general & internal medicine ,Oncotype DX ,business - Abstract
Background We used two models to simulate a proposed noninferiority trial of radiotherapy (RT) omission in low-risk invasive breast cancer to illustrate how modeling could be used to predict the trial's outcomes, inform trial design, and contribute to practice debates. Methods The proposed trial was a prospective randomized trial of no-RT vs RT in women age 40 to 74 years undergoing lumpectomy and endocrine therapy for hormone receptor-positive, human epidermal growth factor receptor 2-negative, stage I breast cancer with an Oncotype DX score of 18 or lower. The primary endpoint was recurrence-free interval (RFI), including locoregional recurrence, distant recurrence, and breast cancer death. Noninferiority required the two-sided 90% confidence interval of the RFI hazard ratio (HR) for no-RT vs RT to be entirely below 1.7. Model inputs included published data. The trial was simulated 1000 times, and results were summarized as percent concluding noninferiority and mean (standard deviation) of hazard ratios for Model GE and Model M, respectively. Results Noninferiority was demonstrated in 18.0% and 3.7% for the two models. The respective means (SD) of the RFI hazard ratios were 1.8 (0.7) and 2.4 (0.9); most were locoregional recurrences. The mean five-year RFI rates for no-RT vs RT (SD) were 92.7% (2.9%) vs 95.5% (2.2%) and 88.4% (2.0%) vs 94.5% (1.6%). Both models showed little or no difference in breast cancer-specific or overall survival. Alternative definitions of low risk based on combinations of age and grade produced similar results. Conclusions The proposed trial was unlikely to show noninferiority of omitting radiotherapy even using alternative definitions of low-risk, as the endpoint included local recurrence. Future trials regarding radiotherapy should address absolute reduction in recurrence and impact of type of recurrence on the patient.
- Published
- 2018