Breast Cancer Hormone Therapy Adherence Often Falls Short When Radiation Is Skipped
A large U.S. insurance claims study found that fewer than 30% of early-stage breast cancer patients stayed above a standard adherence threshold throughout all five years of endocrine therapy after lumpectomy. Patients who did not receive radiation were more likely to have major gaps in taking the medication, as were younger patients. The results were presented at the ASTRO annual meeting and raise questions about treatment plans that omit radiation while depending on long-term hormone therapy.
A U.S. claims analysis examined 17,025 commercially or Medicaid-insured patients aged 23–64. All had lumpectomy for hormone receptor-positive early-stage disease and started endocrine therapy; 89% also received radiation. Fewer than 30% kept pharmacy refill patterns above a common adherence cutoff across all five years. Those who skipped radiation and younger patients showed more interruptions.
Endocrine therapy blocks or reduces hormones that can fuel these tumors, but side effects may include hot flashes, fatigue, joint pain, bone changes, and memory or concentration problems. The findings were presented at the ASTRO annual meeting.
This study may prompt clinicians and patients to weigh whether radiation-omission plans are realistic when they depend on years of daily medication. Patients with early-stage breast cancer, especially younger people and those forgoing radiation, could be most affected if adherence gaps lead to more recurrences or altered follow-up. It may also encourage clearer discussions about side-effect management and support, though claims data cannot prove cause or capture why patients stop treatment.