Regional Radiation Pneumonitis After SIRT of a Subcapsular Liver Metastasis: What is the Effect of Direct Beta Irradiation?

Abstract

We herein present a patient undergoing selective internal radiation therapy with an almost normal lung shunt fraction of 11.5%, developing histologically proven radiation pneumonitis. Due to a predominance of pulmonary consolidations in the right lower lung and its proximity to a large liver metastases located in the dome of the right liver lobe a Monte Carlo simulation was performed to estimate the effect of direct irradiation of the lung parenchyma. According to our calculations direct irradiation seems negligible and RP is almost exclusively due to ectopic draining of radioactive spheres.

The effect of selective internal radiation therapy with yttrium-90 resin microspheres on lung carbon monoxide diffusion capacity

“…SIRT is an established treatment modality for chemoresistant, unresectable, primary, or metastatic hepatic malignancies. During the development phase of this therapeutic modality, tumor-induced arteriovenous pulmonary shunting and possible occurrence of RP emerged as potential limitations of the technique [ 2 , 4 , 24 – 26 ]. Post-treatment development of interstitial pneumonia and presence of micro-spheres in the lung biopsy were reported by Lin et al in 1994 in a hepatocellular carcinoma patient who was treated with resin micro-spheres and who had a pulmonary shunt of 17% [ 24 ].…”

“…After that, Leung et al reported the death of three out of five patients developing RP after SIRT [ 2 ]. While Salem et al observed no clinical radiation pneumonitis in a total of 58 patients receiving higher-than-recommended doses (> 30 Gy) [ 4 ], Dobrocky et al published a case report where an asymptomatic patient had radiation pneumonitis within 3 months following treatment as confirmed both by imaging modalities and lung biopsy [ 26 ].…”

“…In patients who received a repeated treatment, PET/CT images obtained approximately 150 days after the first treatment also showed no pathology. As pointed out by Dobrocky et al who used comparable treatment doses, early identification of asymptomatic radiation pneumonitis patients may bear clinical significance [ 26 ]. As recommended by Sangro et al, detection of the decline in DLCO values may prove to have clinical utility in these patients, particularly when the high radiation exposure associated with CT scans is taken into consideration [ 11 ].…”

Unexpected radiation pneumonitis after SIRT with significant decrease in DLCO with internal radiation exposure: a case report

“…1 Comparison of the planar scintigraphic images of the case (1a, 1b) and reference patient for liver-lung shunt imaging and transaxial fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT-1e 1E) / computed tomography (CT-1c, 1d, 1f) images obtained after selective internal radiation therapy (SIRT) RP [15]. Dobrocky et al published a case report without related DLCO values where an asymptomatic patient had RP as confirmed both by imaging modalities and histopathologic evaluation [9].…”

“…After this case report, Leung et al stated the mortality rate of 60% in five patients who developed RP after the same treatment [3]. In 2015, another asymptomatic patient who was diagnosed with RP after SIRT as verified both by histopathologic examination and imaging findings was published by Dobrocky et al [9].…”