title: Radiation pneumonitis in breast cancer patients who received radiotherapy using the partially wide tangent technique after breast conserving surgery.
abstract: OBJECTIVE
  We assessed the risk of radiation pneumonitis (RP) in terms of dosimetric parameters in breast cancer patients, who received radiotherapy using the partially wide tangent technique (PWT), following breast conservation surgery (BCS).
  
  
  METHODS
  We analyzed the data from 100 breast cancer patients who underwent radiotherapy using PWT. The entire breast, supraclavicular lymph node, and internal mammary lymph node (IMN) were irradiated with 50.4 Gy in 28 fractions. RP was scored on a scale of 0 to 5, based on Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity criteria. The dosimetric parameters, used in analysis for the ipsilateral lung, were the mean lung dose (MLD), V(5) (percentage of lung volume that received a dose of 5 Gy or more)-V(50), and normal tissue complication probability (NTCP).
  
  
  RESULTS
  Of the 100 patients, three suffered from symptomatic RP (symptom grade ≥2), but were relieved by supportive care. The risk of RP was not correlated with the treatment regimen. RP associated mostly with asymptomatic minimal pulmonary radiologic change or mild dry cough developed more frequently in the group with MLD ≥20.5 Gy or NTCP ≥23% than in the group with MLD <20.5 Gy and NTCP <23% (48.6% vs. 25.4%, p=0.018).
  
  
  CONCLUSIONS
  Dosimetric parameters of MLD and NTCP were correlated with the incidence of RP, but the clinical impact was minimal. We suggest that PWT is a safe technique for the treatment of IMN for BCS patients with low risk of symptomatic RP.
authors.affiliation: Department of Radiation Oncology, Yonsei Cancer Center, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yoonsun
authors.initials: Y
authors.lastname: Chung
authors.forename: Hong In
authors.initials: HI
authors.lastname: Yoon
authors.forename: Yong Bae
authors.initials: YB
authors.lastname: Kim
authors.forename: Seung Kwon
authors.initials: SK
authors.lastname: Ahn
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Keum
authors.forename: Chang-Ok
authors.initials: CO
authors.lastname: Suh
keywords: Breast neoplasms; Conformal radiotherapy; Lymphatic irradiation; Radiation pneumonitis