BACKGROUND AND PURPOSE:

• Palmér et al. (JNCI: Journal of the National Cancer Institute, 2025) assessed whether postoperative radiotherapy (RT) could safely be omitted in women ≥65 years old with low-risk, estrogen receptor–positive T1N0 breast cancer

METHODS:

• Prospective national multicenter cohort study
  • Swedish Breast Cancer Group
• Participants
  • Women ≥65 years
  • Unifocal, nonlobular, grade 1 or 2, estrogen receptor–positive, T1N0 (≤2 cm and node negative) breast cancer
  • Treated with breast-conserving surgery and endocrine therapy for 5 years
• Exposures
  • Omission of postoperative RT
• Study design
  • Patients were followed up with mammography at least annually for 10 years
• Primary outcome
  • Local recurrence
• Secondary outcomes
  • Contralateral breast cancer
  • Recurrence-free survival
  • Overall survival

RESULTS:

• 601 participants
  • Median age: 71 (range, 65 to 90)
  • Median tumor size: 11 (range, 3 to 20) mm
  • Median follow-up: 119 (range, 103 to 121) months
• Cumulative incidence of local recurrence
  • At 5 years: 1.5% (95% CI, 0.8 to 2.8)
  • At 10 years: 5.5% (95% CI, 3.8 to 7.6)
• Cumulative incidence of contralateral breast cancer
  • At 5 years: 1.7% (95% CI, 0.9 to 3.0)
  • At 10 years: 4.5% (95% CI, 3.0 to 6.6)
• Overall survival rate at 10 years: 83.1% (95% CI, 80.8 to 85.4)
• Deaths due to breast cancer: 0.5%

CONCLUSION:

• Omitting radiation after breast-conserving surgery may be safe for women 65 or older with low-risk, ER+ breast cancer
• The authors conclude

The long-term results of this prospective cohort study add to the growing body of evidence indicating that withholding RT in a selected cohort of low-risk patients with breast cancer is safe and could be an option for patients fulfilling these criteria

Learn More – Primary Sources:

Omission of postoperative radiotherapy after breast-conserving surgery in low-risk breast cancer