"Many radiation oncologists routinely deliver a boost after WBRT for DCIS, anticipating a similar benefit to our experience with invasive cancers. But we haven't had consistent data to demonstrate this benefit in DCIS. Our study has demonstrated that the use of a radiation boost provides an albeit small but significant long-term benefit in reducing breast tumor recurrence for DCIS patients and supports the consideration of a DCIS boost in patients undergoing WBRT who have life expectancies of 10 or more years," said Meena Savur Moran, MD, lead study author, professor of therapeutic radiology at Yale School of Medicine and director of the Radiation Oncology Breast Program at Smilow Cancer Hospital at Yale New Haven.

The benefit in reducing in-breast recurrence was demonstrated across all DCIS age subgroups. Furthermore, treatment with the DCIS boost was an independent predictor for decreasing IBTR on multivariate analyses controlling for other patient and disease characteristics (i.e., grade, necrosis, margin status, patient age, tumor size and use of tamoxifen). On subset analysis, though the boost did not convey a statistically significant benefit in the subset of patients with positive margins (p = 0.99), it did independently predict for reducing IBTR in all DCIS age groups with negative margins (all p


"Our findings suggest that adding several additional fractions of radiation directed to the lumpectomy cavity after whole breast radiation for DCIS provides an incremental benefit in decreasing local relapse, similar in magnitude to the four percent at 20 years benefit of the boost for invasive cancers," said Dr. Moran. "While these small numbers may not seem substantial, the invasive boost data have highlighted to us the clinical importance that small decreases in local relapse provide for patients. Ultimately, these small decreases in IBTR resulted in reduced the number of mastectomies for recurrence by approximately 40 percent in patients who had received a boost, compared with no-boost."

The abstract, "Radiation Boost for Ductal Carcinoma In Situ After Whole Breast Radiation Therapy (WBRT) Improves Local Control: Analysis from Ten Pooled Academic Institutions," will be presented in detail during a scientific session at ASTRO's 58th Annual Meeting at 1:30 p.m. Eastern time on Tuesday, September 27, 2016. To speak with Dr. Moran or obtain a copy of the study abstract, please contact ASTRO's media relations team on-site at the Boston Convention and Exhibition Center September 25 through 28, by phone at 703-286-1600 or by email at press@astro.org.

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