Pre-radiotherapy FDG PET predicts radiation pneumonitis in lung cancer

Abstract

BackgroundA retrospective analysis is performed to determine if pre-treatment [18 F]-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) image derived parameters can predict radiation pneumonitis (RP) clinical symptoms in lung cancer patients.Methods and MaterialsWe retrospectively studied 100 non-small cell lung cancer (NSCLC) patients who underwent FDG PET/CT imaging before initiation of radiotherapy (RT). Pneumonitis symptoms were evaluated using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) from the consensus of 5 clinicians. Using the cumulative distribution of pre-treatment standard uptake values (SUV) within the lungs, the 80th to 95th percentile SUV values (SUV80 to SUV95) were determined. The effect of pre-RT FDG uptake, dose, patient and treatment characteristics on pulmonary toxicity was studied using multiple logistic regression.ResultsThe study subjects were treated with 3D conformal RT (n = 23), intensity modulated RT (n = 64), and proton therapy (n = 13). Multiple logistic regression analysis demonstrated that elevated pre-RT lung FDG uptake on staging FDG PET was related to development of RP symptoms after RT. A patient of average age and V30 with SUV95 = 1.5 was an estimated 6.9 times more likely to develop grade ≥ 2 radiation pneumonitis when compared to a patient with SUV95 = 0.5 of the same age and identical V30. Receiver operating characteristic curve analysis showed the area under the curve was 0.78 (95% CI = 0.69 – 0.87). The CT imaging and dosimetry parameters were found to be poor predictors of RP symptoms.ConclusionsThe pretreatment pulmonary FDG uptake, as quantified by the SUV95, predicted symptoms of RP in this study. Elevation in this pre-treatment biomarker identifies a patient group at high risk for post-treatment symptomatic RP.

Personalized Radiation Therapy (PRT) for Lung Cancer

“…The 95th percentile of the FDG uptake in the lungs remained significant in multivariable logistic regression (p = 0.016; odds ratio [OR] = 4.3). Castillo R et al performed similar work and confirmed that FDG uptake in pre-RT PET predict RILT [92], another potential tool to guide PRT.…”

“…In NSCLC, SUV measures of FDG uptake on the PET image before RT may also be used as a biomarker to predict radiation induced lung toxicity [91,92]. The hypothesis is that pretreatment inflammation in the lung makes pulmonary tissue more susceptible to radiation damage.…”

Evaluation of the preventive effect of dexpanthenol in radiation injury by lung perfusion scintigraphy

“…In addition, a review noted that SPECT imaging may be more efficient than planar imaging in estimating overall pulmonary function [20]. According to a retrospective analysis, upper lung lobes have a higher metabolic radiation response compared with lower lobes when taking into account PET results [18]. This study also suggested 5 Gy radiation as a limiting dose -that is, below this level there may not be enough injury to allow observation.…”

“…Recent studies have shown that 18 F-FDG PET additionally predicts which patients will have a tendency for radiation pneumonitis before RT [18]. We already know that 18 F-FDG PET imaging shows early changes related to radiation injury: it is not recommended that 18 F-FDG PET imaging be performed early after RT in routine practice. The rationale for this time delay between imaging and therapy is that considerably increased activity, as a consequence of RT, may obscure other pathologies.…”

“…In addition, 67 Ga scintigraphy has been reported to indicate the presence of radiation pneumonitis early in the course of the disease [5], whereas a previous study has suggested that 111 In pentetreotide imaging may better delineate the disease [6]. Among these methods, 18 F-FDG PET serves as a positive marker (identifying an accumulation of increased activity related to radiation injury) and lung scintigraphy serves as a negative marker (identifying hypoperfusion).…”