"Bottom Line Lumpectomy plus radiation was associated with a small clinical benefit in reduced risk of breast cancer death compared with lumpectomy or mastectomy alone in women with ductal carcinoma in situ DCIS a noninvasive early form of breast cancer. Why The Research Is Interesting Patients with DCIS are often treated with radiation after lumpectomy although it has remained unclear whether this can reduce the risk of dying from breast cancer. Who and When More than  U.S. women who had DCIS between  and  this study compared lumpectomy plus radiation vs. lumpectomy alone lumpectomy vs. mastectomy and lumpectomy plus radiation vs. mastectomy What Study Measures and Outcomes Use of radiation andor extent of surgery exposures breast cancer mortality rates within  years outcomes How Study Design This was an observational study. Researchers were not intervening for purposes of the study and cannot control all the natural differences that could explain the study findings. Authors  Steven A. Narod M.D. of Womens College Research Institute in Ontario Canada and coauthors Results A small improvement in breast cancer survival was associated with radiation plus lumpectomy for DCIS. The absolute risk reduction was . percent making it necessary to treat  women to save one life. Patients who had lumpectomy plus radiation had more local recurrences than the mastectomy patients but had fewer deaths. Study Limitations Some data were missing investigators didnt have information on tamoxifen use treatments in the study population werent randomly assigned and the possibility remains that the decision to undergo radiotherapy was associated with other favorable prognostic factors. Related Material The invited commentary Systemic Effects of Radiotherapy in Ductal Carcinoma In Situ by Mira Goldberg M.D. and Timothy J. Whelan B.M. B.Ch. of McMaster University Ontario Canada also is available on the For The Media website httpmedia.jamanetwork.com. To Learn More The full study is available on the For The Media website httpsmedia.jamanetwork.com. doi.jamanetworkopen.. Editors Note The article contains conflict of interest disclosures. Please see the article for additional information including other authors author contributions and affiliations financial disclosures funding and support etc.  Want to embed a link to this study in your story Links will be live at the embargo time httpjamanetwork.comjournalsjamanetworkopenfullarticle.jamanetworkopen.. About JAMA Network Open JAMA Network Open is the new onlineonly open access general medical journal from the JAMA Network. Every Friday the journal publishes peerreviewed clinical research and commentary in more than  medical and health subject areas. Every article is free online from the day of publication."