Disease Control Efficacy of Ductal Carcinoma In Situ (DCIS) Treated With Accelerated Partial Breast Irradiation (APBI)

RTOG/EORTC Late Radiation Morbidity systems were used for evaluation of skin, subcutaneous and non-cutaneous toxicities. Median follow-up was 82.5 months (range, 2-104 months). Results: At 4 years, the physician rating of overall cosmesis was good or excellent for 94% of photon patients, compared to 77% of proton patients, with fair or poor results for 6% and 27%, respectively (p Z 0.05). The incidence between the groups were: telangiectasia 11% for photon and 73% for proton patients (p < 0.01); any skin color change, 14% and 60% (p < 0.01); and late atrophy, 19% and 67% (p < 0.01). There were no significant differences between the groups in the incidences of breast pain, edema, fibrosis, fat necrosis, skin desquamation or rib pain or fracture. Patient-reported cosmetic outcomes at 4 years did not significantly differ (good or excellent for 95% of photon patients and 93% of proton patients) (p Z 0.4). There were no differences in breast pain, swelling, skin color or overall satisfaction. Conclusions: Proton 3D-APBI, with a single field used per treatment, led to higher rates of telangiectasia, skin color change and atrophy than treatment with photon or mixed photon and electron plans using 3 or more fields per treatment. Multiple fields per treatment should be used with proton 3D-APBI, similarly to photon 3D-APBI, to minimize the per day integral dose to normal tissue. Pencil beam scanning and other techniques should be explored to reduce proton APBI toxicity. Author Disclosure: S. Galland: None. I.M. Pashtan: None. S.M. MacDonald: None. M. Ancukiewicz: None. M. Specht: None. M.A. Gadd: None. B.L. Smith: None. A. Recht: G. Consultant; medical advisory board of CareCore National, Inc. A.G. Taghian: None.