Predicting risk factors for radiation pneumonitis after stereotactic body radiation therapy for primary or metastatic lung tumours.

OBJECTIVE: To investigate risk factors for radiation-induced pneumonitis (RP) after hypofractionated stereotactic body radiotherapy (SBRT) in patients with lung tumours. METHODS: From May 2004 to January 2016, 66 patients with 71 primary or metastatic lung tumours were treated with SBRT; these 71 cases were retrospectively analyzed for RP. To explore the risk factors for RP, the following factors were investigated: age, sex, performance status, operability, number of treatments, respiratory gating, pulmonary emphysema, tumour location and subclinical interstitial lung disease (ILD). Irradiated underlying lung volumes of more than 5 Gy, 10 Gy, 20 Gy and 30 Gy (Lung V5, V10, V20 and V30), mean lung dose and volumes of gross tumour volume (in cubic centimetre) and planning target volume were calculated for possible risk factors of RP. RESULTS: The median follow-up period was 32 months. RP of Grade 2 or more, according to the Common Terminology Criteria for Adverse Events v. 4.0, was detected in 6 (8.4%) of the 71 cases. Grade 5 RP was identified in two cases. Of the risk factors of RP, subclinical ILD was the only factor significantly associated with the occurrence of RP of Grade 2 or more (p < 0.001). Both cases with Grade 5 RP had ILD with a honeycombing image. CONCLUSION: Subclinical ILD was the only significant factor for Grade 2-5 RP. In addition, the cases with honeycombing had a high potential for fatality related to severe RP. Patients with subclinical ILD should be carefully monitored for the occurrence of severe RP after SBRT. Advances in knowledge: Hypofractionated SBRT for primary or metastatic lung tumours provides a high local control rate and safe treatment.

Impact of the duration of hormonal therapy following radiotherapy for localized prostate cancer.

External-beam radiotherapy (EBRT) combined with androgen deprivation therapy (ADT) is known to provide improved survival outcomes compared with EBRT alone in the treatment of prostate cancer; however, the use of ADT has been reported to be associated with adverse events. Accordingly, the aim of the present study was to clarify the adequate duration of ADT when combined with EBRT to treat patients with high-risk localized prostate cancer, with consideration of survival outcomes and toxicity. Between 2001 and 2011, 173 patients with high-risk localized prostate cancer received ADT combined with EBRT, at a median dose of 69.6 Gy. Of these, 54 (31%) underwent short-term ADT (<36 months) and 119 (69%) underwent long-term ADT (≥36 months). During the median follow-up period of 54 months, the five-year progression-free survival rate of patients receiving short-term ADT (72.9%) was significantly lower than that of patients receiving long-term ADT (92.8%) (P<0.01). Furthermore, the incidence of cardiovascular toxicity at grade II or above was significantly higher amongst patients treated with short-term ADT compared with patients treated with long-term ADT (P<0.01). Thus, the present study determined that ADT for ≥36 months combined with EBRT significantly improved the progression-free survival of patients with high-risk localized prostate cancer and exhibited an acceptable toxicity profile.