Symptomatic Radiation Pneumonitis After Accelerated Partial Breast Irradiation Using Three-dimensional Conformal Radiotherapy

Aim: To examine the relationship between symptomatic radiation pneumonitis and lung dose-volume parameters for patients receiving accelerated partial breast irradiation (APBI) using three dimensional-conformal radiotherapy (3D-CRT). Patients and Methods: The prescribed radiation dose was 30 Gy in 5 fractions over 10 days. Toxicity was graded according to the Common Terminology Criteria for Adverse Events (version 4.0). Results: Fifty-five patients were enrolled from August 2010 to October 2013 and the median follow-up time was 30 months (range=18-46 months). Three patients (5%) developed grade 2 symptomatic radiation pneumonitis after 3D-CRT APBI. Among 16 patients with ILV10Gy (% ipsilateral lung receiving >= 10 Gy) of 10% or higher, three patients (19%) developed symptomatic radiation pneumonitis. This trend was not observed in any of the patients with ILV10Gy less than 10% (p=0.005). Conclusion: High ILV10Gy might be associated with symptomatic radiation pneumonitis after 3D-CRT APBI.