ESTRO Multidisciplinary Management of Breast Cancer 2017

Partial breast irradiation in DCIS

• DCIS is considered suitable for PBI, if acc. to RTOG 9804 low risk: • Screen-detected, Grade 1-2, ≤ 2.5 cm, free margins ≥ 3 mm

• IBTR risk w/o RT: 6.7% at 7.2 yr (RTOG 9804) • IBTR risk w/o RT: 14.2% at 12 yr (ECOG E 5194)

• Applying these criteria to APBI with mammosite: • 40 patients: 5 yr risk IBTR 0%

• Pooled analysis DCIS treated with mammosite: • 300 patients, 5 yr IBTR 2.5%

“These patients could also be offered endocrine Rx or observation alone”

• RCTs PBI vs WBRT for DCIS are underway..!