Boost your knowledge.

August 22, 2017. Delivering an additional radiation dose to (i.e., boosting) the lumpectomy cavity in Stage 0 ductal carcinoma in-situ (DCIS) patients is routinely performed. But why? Last month’s answer: extrapolation. We’ve known since 2000 that radiation (sans boost) improves local control in DCIS per EORTC 10853. Soon after, the initial reporting in 2001 of EORTC 22881 for Stage I-II invasive breast cancer showed that an additional 8 treatments totaling 16 Gy to the lumpectomy site (after 50 Gy to whole breast as used in EORTC 10853) further slashes risk of local recurrence by almost half across the board--with highest absolute benefit, of course, seen for those at highest absolute risk (e.g., younger women). But this came at the expense of almost tripling fibrosis in the long-run. This month’s JAMA Onc pub arms us with DCIS-specific retrospective data on >4K patients receiving a boost. A persistent relative risk reduction in local recurrence of approximately one-third was seen across all ages and pathologies. In practice, we suggest using this new data along with a DCIS nomogram and individual patient preference to answer the age-old adage: to boost, or not to boost.