HL-172 FDG-PET/CT as a Tool for Early Detection of Bleomycin-Induced Pulmonary Toxicity

Abstract

Bleomycin pulmonary toxicity (BPT) is a serious and potentially fatal complication of bleomycin, a key component of Hodgkin lymphoma (HL) treatment. Before ours, only one published study evaluated the predictability of FDG-PET/CT in the diagnosis of BPT. We aimed to determine whether FDG-PET/CT changes correlate with clinical BPT. Additionally, we assessed the correlation of clinical BPT with sociodemographic and disease characteristics. In this retrospective study, FDG-PET/CT scans of adult (age >18 years) HL patients treated with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) at a single urban academic center, University of Cincinnati Medical Center, from 2012 to 2016 were evaluated for pulmonary toxicity and then assessed for the development of clinical BPT. The images were evaluated by 2 separate radiologists, for whom the clinical information was anonymized. All P-values were two-sided; P<0.05 was considered statistically significant. Data were analyzed using SAS 9.4 software. We found 54 FDG-PET/CT scans from 11 patients who received bleomycin for HL. Five of the 11 (45%) patients had radiographic changes that were characteristically focal or diffuse opacities on PET/CT and developed clinical BPT. One patient had radiological changes but did not develop clinical BPT, whereas the other five had no signs of toxicity on imaging. Patients with clinical BPT had higher SUVmax than those without (mean [CI] 2.66 [1.8-3.7] vs. 0.86 [0.4-1.9], P<0.05, Mann-Whitney U test). In a separate analysis, we compared patients with clinical BPT (9/25, 36%) and without (16/25, 64%). Patients with clinical BPT had lower hemoglobin (mean 10.9 vs. 13.3 g/dL, P=0.037) and higher ESR (mean 63.3 vs. 30.2 mm/hr, P=0.0289). We found that gender, stage, histology, history of lung radiation, prior G-CSF, and steroids did not significantly confer a higher risk of BPT. Patients with bulky disease and prior lung disease had a higher risk of clinical BPT; however, the correlation was not statistically significant. We conclude that FDG-PET/CT imaging, which is routinely used to assess treatment response in HL, is useful for early detection and guiding interventions for BPT. Hemoglobin and ESR at diagnosis can be predictive of BPT; further studies are needed.