Association of Radiotherapy With Survival in Women Treated for Ductal Carcinoma In Situ With Lumpectomy or Mastectomy

Key Points Question Is adjuvant radiation associated with a reduction in breast cancer mortality in patients treated for ductal carcinoma in situ? Findings Using a matched approach in a large cohort of patients treated for ductal carcinoma in situ, treatment with lumpectomy and radiotherapy was associated with a significantly reduced risk of breast cancer–specific mortality compared with treatment with lumpectomy alone (hazard ratio, 0.77; 95% CI, 0.67-0.88) or mastectomy alone (hazard ratio, 0.75; 95% CI, 0.65-0.87). Meaning Adjuvant radiation is associated with a small but significant breast cancer survival benefit in patients with ductal carcinoma in situ that cannot be accounted for by enhancing local control.