Interstitial Lung Change in Pre-radiation Therapy Computed Tomography Is a Risk Factor for Severe Radiation Pneumonitis

Abstract

PurposeWe examined clinical and dosimetric factors as predictors of symptomatic radiation pneumonitis (RP) in lung cancer patients and evaluated the relationship between interstitial lung changes in the pre-radiotherapy (RT) computed tomography (CT) and symptomatic RP.Materials and MethodsMedical records and dose volume histogram data of 60 lung cancer patients from August 2005 to July 2006 were analyzed. All patients were treated with three dimensional (3D) conformal RT of median 56.9 Gy. We assessed the association of symptomatic RP with clinical and dosimetric factors.ResultsWith a median follow-up of 15.5 months (range, 6.1 to 40.9 months), Radiation Therapy Oncology Group grade ≥ 2 RP was observed in 14 patients (23.3%). Five patients (8.3%) died from RP. The interstitial changes in the pre-RT chest CT, mean lung dose (MLD), and V30 significantly predicted RP in multivariable analysis (p=0.009, p < 0.001, and p < 0.001, respectively). MLD, V20, V30, and normal tissue complication probability normal tissue complication probability (NTCP) were associated with the RP grade but less so for grade 5 RP. The risk of RP grade ≥ 2, ≥ 3, or ≥ 4 was higher in the patients with interstitial lung change (grade 2, 15.6% to 46.7%, p=0.03; grade 3, 4.4% to 40%, p=0.002; grade 4, 4.4% to 33.3%, p=0.008). Four of the grade 5 RP patients had diffuse interstitial change in pre-RT CT and received chemoradiotherapy.ConclusionOur study identified diffuse interstitial disease as a significant clinical risk for RP, particularly fatal RP. We showed the usefulness of MLD, V20, V30, and NTCP in predicting the incidence and severity of RP.

Incidence, Risk Factors, and Effect on Survival of Immune-related Adverse Events in Patients With Non–Small-cell Lung Cancer

“…The risk factors for radiation pneumonitis have been reported to include the timing and schedule of RT sessions, the mean lung dose, the target volume and dose, pre-existing lung disease, and circulating cytokines. [22][23][24] The risk factors for immunotherapy-related pneumonitis have not been defined; however, suggestions have included active smoking, which we were unable to confirm in our study. 25 Little is known about which risk factors increase the likelihood of irAEs overall and pneumonitis in particular, and what effect irAEs might have on survival.…”

Clarithromycin mitigates radiation pneumonitis in patients with lung cancer treated with stereotactic body radiotherapy

“…Radiation pneumonitis is one of the most critical pulmonary toxicities following SBRT for lung tumors. Many previous radiation pneumonitis studies have investigated risk factors (12,(28)(29)(30)(31), dose-volumetric analyses (32,33), and prophylactic drugs (34,35).…”

“…IIPs are one risk factor for the development of radiation pneumonitis (30,31). Several reports have suggested that radiation pneumonitis ≥ grade 3 in patients with IIPs may have certain etiological features in common with acute exacerbations of IIPs (7)(8)(9)(10)(11)(12).…”

Stereotactic body radiotherapy for second primary lung cancer and intra-parenchymal lung metastasis in patients previously treated with surgery: evaluation of indications and predictors of decreased respiratory function

“…Lee et al reported that the interstitial changes in the pre-RT chest CT scan (p ¼ .009), mean lung dose (p < .001), and the percentage of lung volume receiving over 30 Gy (V30) (p < .001) significantly predicted RP on multivariate analysis. Therefore, despite the comparatively small field and minimal irradiation volume of SBRT, clinicians should consider the possibility of exacerbated IP [25].…”