(P008) Pretreatment FDG Uptake of Nontarget Lung Tissue Correlates With Symptomatic Pneumonitis Following Stereotactic Ablative Radiotherapy (SABR)

OncologyOncology Vol 29 No 4_Suppl_1
Volume 29
Issue 4_Suppl_1

Patients with higher nontarget lung FDG avidity appear to be at greater risk forradiation pneumonitisfollowing SABR.

Aadel A. Chaudhuri, MD, PhD, Michael S. Binkley, BA, Justin N. Carter, BA, Maximilian Diehn, MD, PhD, Billy W. Loo, MD, PhD; Stanford University School of Medicine

INTRODUCTION: Radiation pneumonitis (RP) is the most common toxicity associated with radiation therapy to the lung. It can be debilitating and even life-threatening, especially since many patients with lung malignancies have other pulmonary comorbidities. Here, we report our institution’s experience in using pretreatment positron emission tomography-computed tomography (PET-CT) to calculate baseline nontarget lung fluorodeoxyglucose (FDG) avidity, which we have found to be significantly associated with symptomatic RP following stereotactic ablative radiotherapy (SABR).

METHODS: We retrospectively reviewed outcomes in 73 patients with lung tumors treated with SABR. All patients underwent whole body PET-CT and four-dimensional (4D) chest CT simulation scan within 2 weeks prior to treatment. Gross tumor volume (GTV) was contoured on axial CT slices using lung windows. Respiration-induced motion was assessed by 4D CT, used to design the internal target volume (ITV), and a 0.5-cm margin was added to form the planning target volume (PTV). Total lung minus PTV and ipsilateral lung minus PTV were contoured using lung windows. All contouring was done using Varian Eclipse and MIM software. We used the simulation PET-CT scans to calculate the standard uptake value (SUV) at the 85th (SUV85), 90th (SUV90), and 95th (SUV95) percentiles and mean SUV for total lung minus PTV and ipsilateral lung minus PTV using MIM and compared these values between patients who experienced symptomatic RP and those who did not. All strata were compared using Student’s t-test and Cox regression for univariate and multivariate analyses.

RESULTS: Median follow-up time was 15 months (range: 4–45 mo). A total of 70 patients (95.9%) were treated for T1 to T3 non–small-cell lung cancer, while 3 (4.1%) were treated for oligometastatic disease from non-lung primary cancers. Sixty-six patients (90.4%) were treated for one lung tumor, and seven patients (9.6%) were treated for two lung tumors. Sixteen patients (21.9%) experienced grade ≥ 2 RP, 3 of whom experienced grade ≥ 3 RP. Median time to pneumonitis was 4.95 months (range: 2.5–24 mo). Analysis of simulation PET-CT scans from all patients revealed that those who experienced grade ≥ 2 RP had significantly higher total lung minus PTV SUV85 (P = .0005), SUV90 (P = .0014), and SUV95 (P = .0078) than those with no symptomatic pneumonitis. We saw similar results when we analyzed ipsilateral lung minus PTV, with significantly higher baseline SUV85 (P = .0021), SUV90 (P = .0036), SUV95 (P = .0108), and mean SUV (P = .0012) in patients who experienced grade ≥ 2 RP. A significant association was observed between grade ≥ 2 RP and total lung minus PTV SUV85 on univariate (hazard ratio [HR] = 28.9; 95% confidence interval [CI], 3.66–216.61; P = .001) and multivariate (HR = 25.22; 95% CI, 3.3–192.94; P = .002) analysis.

CONCLUSION: Patients with higher nontarget lung FDG avidity appear to be at greater risk forradiation pneumonitisfollowing SABR.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org

Articles in this issue

(P005) Ultrasensitive PSA Identifies Patients With Organ-Confined Prostate Cancer Requiring Postop Radiotherapy
(P001) Disparities in the Local Management of Breast Cancer in the United States According to Health Insurance Status
(P002) Predictors of CNS Disease in Metastatic Melanoma: Desmoplastic Subtype Associated With Higher Risk
(P003) Identification of Somatic Mutations Using Fine Needle Aspiration: Correlation With Clinical Outcomes in Patients With Locally Advanced Pancreatic Cancer
(P004) A Retrospective Study to Assess Disparities in the Utilization of Intensity-Modulated Radiotherapy (IMRT) and Proton Therapy (PT) in the Treatment of Prostate Cancer (PCa)
(S001) Tumor Control and Toxicity Outcomes for Head and Neck Cancer Patients Re-Treated With Intensity-Modulated Radiation Therapy (IMRT)-A Fifteen-Year Experience
(S003) Weekly IGRT Volumetric Response Analysis as a Predictive Tool for Locoregional Control in Head and Neck Cancer Radiotherapy 
(S004) Combination of Radiotherapy and Cetuximab for Aggressive, High-Risk Cutaneous Squamous Cell Cancer of the Head and Neck: A Propensity Score Analysis
(S005) Radiotherapy for Carcinoma of the Hypopharynx Over Five Decades: Experience at a Single Institution
(S002) Prognostic Value of Intraradiation Treatment FDG-PET Parameters in Locally Advanced Oropharyngeal Cancer
(P006) The Role of Sequential Imaging in Cervical Cancer Management
(P008) Pretreatment FDG Uptake of Nontarget Lung Tissue Correlates With Symptomatic Pneumonitis Following Stereotactic Ablative Radiotherapy (SABR)
(P009) Monte Carlo Dosimetry Evaluation of Lung Stereotactic Body Radiosurgery
(P010) Stereotactic Body Radiotherapy for Treatment of Adrenal Gland Metastasis: Toxicity, Outcomes, and Patterns of Failure
(P011) Stereotactic Radiosurgery and BRAF Inhibitor Therapy for Melanoma Brain Metastases Is Associated With Increased Risk for Radiation Necrosis
Related Videos
Administering immunotherapy following surgery in patients with early-stage triple-negative breast cancer does not appear to be as effective as beginning with neoadjuvant treatment, says Peter Schmid, MD, PhD.
Heather A. Parsons, MD, MPH, says she is excited about HER2 as a biomarker and investigating the biology of metastatic breast cancer with a minimally invasive liquid biopsy platform.
Cretostimogene grenadenorepvec’s efficacy compares favorably with the current nonsurgical standards of care in high-risk, Bacillus Calmette Guerin–unresponsive non-muscle invasive bladder cancer.
Artificial intelligence models may be “seamlessly incorporated” into clinical workflow in the management of prostate cancer, says Eric Li, MD.
Robust genetic testing guidelines in the prostate cancer space must be supported by strong clinical research before they can be properly implemented, says William J. Catalona, MD.
Treatment with tisotumab vedotin may be a standard of care in second- or third-line recurrent or metastatic cervical cancer, says Brian Slomovitz, MD, MS, FACOG.
Future analyses will look at durvalumab/olaparib for endometrial cancer populations with TP53 and POLE alterations, as well as those with estrogen receptor and progesterone receptor positivity.
Related Content