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

Abstract

Background: In the last years, Selective Internal Radiation Therapy (SIRT), using biocompatible Yttrium-90 (90Y) labeled microspheres have emerged for the treatment of malignant hepatic tumors. Unfortunately, a significant part of 90Ylabeled microspheres may shunt to the lungs after intraarterial injection. It can be predictable by infusing technetium-99 m-labeled macro-aggregated albumin particles through a catheter placed in the proper hepatic artery depending on the lobe to be treated with performing a quantitative lung scintigraphy. Radiation pneumonitis (RP) can occur 1 to 6 months after the therapy, which is a rare but severe complication of SIRT. Prompt timing of steroid treatment is important due to its high mortality rate. On the other hand, pulmonary diffusion capacity measured by carbon monoxide (DLCO) is an excellent way to measure the diffusing capacity because carbon monoxide is present in minimal amount in venous blood and binds to hemoglobin in the same manner as oxygen. Some authors reported that the most consistent changes after radiation therapy (RT) are recorded with this quantitative reproducible test. The relationship between the proportional reductions in DLCO and the severity of RP developing after this therapy may prove to be clinically significant. Case presentation: We herein present a patient who developed RP after SIRT that could be quantified using DLCO. To the best of our knowledge, this case is the first who developed unexpected RP after SIRT with significant decrease in DLCO with internal radiation exposure. Conclusions: RP is a very rare complication and may lead to a fatal outcome. Decline in DLCO could be a valuable parameter for follow-up and to identify potential candidates for RP and could be also another trigger for administration of steroid therapy with prompt timing in this patient group.

Lung shunt fraction calculation using 99mTc-MAA SPECT/CT imaging for 90Y microsphere selective internal radiation therapy of liver tumors

“…In some cases, investigators chose to treat patients who had high LSF with the systemic drug Sorafenib [26], a protein kinase inhibitor, and over time the repeated LSF was significantly reduced. Furthermore, pre-treatment LSF alone may not be necessarily predictive of the presence of significant hepatopulmonary shunt post-treatment, as seen in the 90 Y Bremsstrahlung images, with the possibility of radiation pneumonitis [27].…”

EANM procedure guideline for the treatment of liver cancer and liver metastases with intra-arterial radioactive compounds

“…In patients with a considerable lung shunt fraction on pre-treatment 99m Tc-MAA scintigraphy, image acquisition should comprise the whole liver and lungs. Post-treatment planar imaging covering the lung region is advisable to identify unexpected lung shunt and complications that can be investigated more in detail with 3D modality [ 103 , 104 ]. In the absence of a clinically relevant lung shunt fraction, coverage of the lungs is not necessary.…”

Complications of 90Y Radioembolization Treatment for Liver Tumors

“…At the conclusion of the mapping angiogram, 99m-technetium-labeled macroaggregated albumin (Tc-MAA) is injected into the hepatic artery, and then a SPECT is performed to evaluate the degree of uptake into the lungs, and a lung shunt fraction (LSF) can be calculated. 34 If the potential delivery to the lung is more than 30 Gy for a single injection or more than 50 Gy from cumulative injections, radioembolization is contraindicated. For resin microspheres, LSF cutoffs can also be used.…”