TITLE:
Factors Predicting the Relapse of Radiation-Induced Organizing Pneumonia after Breast-Conserving Therapy
AUTHORS:
Yukinori Okada, Shingo Sakamoto, Tatsuyuki Abe, Mio Shinozaki, Hiromichi Gomi, Yoshihide Kanemaki, Shin Matsuoka, Yasuo Nakajima
KEYWORDS:
Radiation-Induced Organizing Pneumonia, Breast-Conserving Therapy, Tangential Irradiation, C-Reactive Protein
JOURNAL NAME:
Open Journal of Radiology,
Vol.5 No.3,
September
16,
2015
ABSTRACT: We investigated the factors predicting radiation-induced organizing pneumonia (RIOP) relapse after tangential breast irradiation. The participants included 23 patients diagnosed with RIOP at the St. Marianna University School of Medicine Hospital between January 2008 and March 2015. Relapse was defined as the appearance of new lesions on diagnostic images during follow-up or after commencing treatment. The relapse-free survival rate and the following 9 parameters were compared between patients with and without RIOP relapse: 1) age (less than vs. equal to or more than the median); 2) white blood cell count (less than vs. equal to or more than the median); 3) C-reactive protein (CRP) level at the time of RIOP diagnosis (less than normal, more than normal/ less than borderline, and more than borderline); 4) boost irradiation (yes vs. no); 5) maximum lung depth on linacgraphy (less than vs. equal to or more than the median); 6) hormone therapy (yes vs. no); 7) chemotherapy (yes vs. no); 8) RIOP ratio in the whole lung (less than vs. equal to or more than the median) at the time of RIOP diagnosis; and 9) use of corticosteroids (yes vs. no). The Kaplan-Meier method was used for statistical analysis, with relapse as the cutoff. The follow-up period spanned the date of RIOP onset to May 30, 2015. The level of significance for 2-sided tests was p