Predicting Radiation Pneumonitis After Stereotactic Ablative Radiation Therapy in Patients Previously Treated With Conventional Thoracic Radiation Therapy

• Published in: International journal of radiation oncology, biology, physics Vol. 84; no. 4; pp. 1017 - 1023
• Main Authors: Liu, Hui, MD, PhD, Zhang, Xu, MD, Vinogradskiy, Yevgeniy Y., PhD, Swisher, Stephen G., MD, Komaki, Ritsuko, MD, Chang, Joe Y., MD, PhD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.11.2012; Elsevier
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Carcinoma, Non-Small-Cell Lung - radiotherapy; Carcinoma, Non-Small-Cell Lung - surgery; Diseases of the respiratory system; Female; Forced Expiratory Volume; HEALTH HAZARDS; Hematology, Oncology and Palliative Medicine; Humans; Incidence; Lung Neoplasms - radiotherapy; Lung Neoplasms - surgery; LUNGS; Male; MEDIASTINUM; Medical sciences; Middle Aged; MULTIVARIATE ANALYSIS; Neoplasm Recurrence, Local - surgery; NEOPLASMS; PATIENTS; PLANNING; Pneumology; PNEUMONITIS; RADIATION DOSES; Radiation Pneumonitis - epidemiology; Radiation Pneumonitis - etiology; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Radiosurgery - adverse effects; Radiosurgery - methods; RADIOTHERAPY; Radiotherapy Dosage; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); REGRESSION ANALYSIS; Retrospective Studies; Risk Factors; Severity of Illness Index; Tumors of the respiratory system and mediastinum; Human; Lung disease; Pneumonia; Respiratory disease; Toxicity; Lung cancer; Radiosurgery; Thorax; Malignant tumor; Radiotherapy; Epidemiology; Incidence; Cancerology; Treatment; Risk factor; Radiation injury; Bronchus disease; Complication; Comparative study; Cancer
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2012.02.020

Purpose To determine the incidence of and risk factors for radiation pneumonitis (RP) after stereotactic ablative radiation therapy (SABR) to the lung in patients who had previously undergone conventional thoracic radiation therapy. Methods and Materials Seventy-two patients who had previously received conventionally fractionated radiation therapy to the thorax were treated with SABR (50 Gy in 4 fractions) for recurrent disease or secondary parenchymal lung cancer (T <4 cm, N0, M0, or Mx). Severe (grade ≥3) RP and potential predictive factors were analyzed by univariate and multivariate logistic regression analyses. A scoring system was established to predict the risk of RP. Results At a median follow-up time of 16 months after SABR (range, 4-56 months), 15 patients had severe RP (14 [18.9%] grade 3 and 1 [1.4%] grade 5) and 1 patient (1.4%) had a local recurrence. In univariate analyses, Eastern Cooperative Oncology Group performance status (ECOG PS) before SABR, forced expiratory volume in 1 second (FEV1), and previous planning target volume (PTV) location were associated with the incidence of severe RP. The V10 and mean lung dose (MLD) of the previous plan and the V10 -V40 and MLD of the composite plan were also related to RP. Multivariate analysis revealed that ECOG PS scores of 2-3 before SABR ( P =.009), FEV1 ≤65% before SABR ( P =.012), V20 ≥30% of the composite plan ( P =.021), and an initial PTV in the bilateral mediastinum ( P =.025) were all associated with RP. Conclusions We found that severe RP was relatively common, occurring in 20.8% of patients, and could be predicted by an ECOG PS score of 2-3, an FEV1 ≤65%, a previous PTV spanning the bilateral mediastinum, and V20 ≥30% on composite (previous RT+SABR) plans. Prospective studies are needed to validate these predictors and the scoring system on which they are based.