HealthDay News — Treatment with lumpectomy and radiotherapy is associated with a reduction in breast cancer mortality vs lumpectomy or mastectomy alone among patients with ductal carcinoma in situ (DCIS), according to a study published online Aug. 10 in JAMA Network Open.
Vasily Giannakeas, M.P.H., from the Women’s College Research Institute in Toronto, and colleagues conducted a cohort study involving women who had first primary DCIS diagnosed between 1998 and 2014. Data came from the Surveillance, Epidemiology, and End Results 18 registries database. The risk of breast cancer mortality was compared for 140,366 women; using 1:1 matching, 3 comparisons were performed: lumpectomy with radiation vs lumpectomy alone; lumpectomy alone vs mastectomy; and lumpectomy with radiation vs mastectomy.
Overall, 25.0% of patients were treated with lumpectomy alone, 46.5% with lumpectomy and radiotherapy, and 28.5% with mastectomy. The researchers found that the actuarial 15-year breast cancer mortality rates were 2.33, 1.74, and 2.26% for patients treated with lumpectomy alone, lumpectomy and radiation, and mastectomy, respectively. For death, the adjusted hazard ratios were 0.77 (95% confidence interval, 0.67 to 0.88) for lumpectomy and radiotherapy vs lumpectomy alone; 0.91 (95% confidence interval, 0.78 to 1.05) for mastectomy alone vs lumpectomy alone; and 0.75 (95% confidence interval, 0.65 to 0.87) for lumpectomy and radiotherapy vs mastectomy.
“The survival benefit of radiation is likely not due to local control, but rather to systemic effects,” the authors write.