A win of omission.
The Study: Many of these patients only need 3 weeks of hypofractionated radiation, anyway. And because we’ve seen less than half of them comply with 5 full years of endocrine therapy, how safe could it be to drop the endocrine therapy? Because it’s unlikely we’ll ever see that trial, this study uses a complex Markov model to simulate the potential outcomes of endocrine therapy alone versus radiation alone specifically in older women with low-risk breast cancer. They used the B-21 trial to inform the potential recurrence outcomes for each. These outcomes were then modified by applying expected hazard ratios for an older, low-risk population. Real-world compliance rates for endocrine and long-term radiation effects were also included. The results were largely what you’d expect, showing reduced rates of contralateral breast cancer and distant mets with endocrine therapy and lower rates of ipsilateral cancer and overall events with radiation. From a cost-effectiveness standpoint, 40 Gy in 15 fractions came out around $4000 more expensive over the patient’s lifetime than endocrine therapy alone.
TBL: In the real-world, omitting endocrine therapy in favor of radiation for older women with low-risk breast cancer may be a safe, and dare we say more effective, alternative than vice versa. | Ward, Int J Radiat Oncol Biol Phys 2019