Informing patient decisions regarding management of ductal carcinoma in situ.

The Institute of Medicine has identified the management of ductal carcinoma in situ (DCIS) as one of the highest priority topics for comparative effectiveness research. With the rise of mammographic screening, the incidence of DCIS has increased dramatically, and currently about a quarter of all newly diagnosed breast cancers are DCIS. Although DCIS is by definition noninvasive, treatment is necessary because of the risk of development into invasive cancer. Therefore, most patients with DCIS face complex management decisions, including whether to undergo breast-conserving surgery or mastectomy, as well as whether to receive adjuvant radiotherapy and/or tamoxifen. In this issue of the Journal, Soeteman and colleagues present an intriguing study using simulation modeling to evaluate the trade-offs in lifetime risks and benefits with various approaches for DCIS management (1). Specifically, they consider mastec-tomy (with or without reconstruction) and four options for native breast conservation (lumpectomy alone, lumpectomy with radiation , lumpectomy with tamoxifen, and lumpectomy with both radiation and tamoxifen). They compare predicted survival and breast preservation rates at three representative ages: 45, 60, and 70 years. Perhaps the greatest contribution of the study is its finding that survival after mastectomy is similar to that after lumpectomy, radiation , and tamoxifen for all three patient ages. A randomized trial of mastectomy versus breast conservation for DCIS is extremely unlikely to be feasible. Therefore, it is useful to be able to refer to these model results to reassure patients that they do not have to sacrifice the native breast to maximize survival. It is also interesting that the model suggests that radiation therapy yields a modest survival advantage. Although none of the randomized trials have demonstrated a difference in survival associated with the use of radiation, physicians have speculated how radiation therapy might, in theory, be lifesaving for a patient with DCIS. If radiation spares a certain number of patients invasive recurrences, some of which eventually lead to metastatic disease, it might indeed offer a survival benefit. However, given the relatively modest absolute reduction in invasive recurrence risk yielded by radiotherapy, and the fact that many recurrences can still be salvaged , the magnitude of any survival benefit would likely be too small to detect even with meta-analysis of all existing trials. The model results support the concept that radiation can improve survival, even for DCIS. Moreover, a survival benefit of a similar magnitude appears to result from the addition of tamoxifen …