Lung Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_29_3602 - Pretreatment CT Based Emphysema and Fibrosis Scoring of Peri-Tumoral Lung Parenchyma Predicts Risk of Radiation Induced Lung Toxicity

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

Pretreatment CT Based Emphysema and Fibrosis Scoring of Peri-Tumoral Lung Parenchyma Predicts Risk of Radiation Induced Lung Toxicity
W. C. Jackson1, P. S. Boonstra2, P. G. Hawkins1, D. R. Owen1, P. Jain1, G. Sun1, D. Arenberg3, E. Lee4, G. P. Kalemkerian5, F. M. Kong6, J. A. Hayman7, T. S. Lawrence1, R. K. Ten Haken1, M. Schipper2, M. M. Matuszak1, and S. Jolly7; 1Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 2Department of Biostatistics, University of Michigan, Ann Arbor, MI, 3Department of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, MI, 4Department of Radiology, University of Michigan, Ann Arbor, MI, 5Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI, 6Indiana University Radiation Oncology, Indianapolis, IN, 7Michigan Medicine, Ann Arbor, MI

Purpose/Objective(s): Many patients receiving radiation (RT) for localized non-small cell lung cancer (NSCLC) harbor underlying pulmonary dysfunction secondary to emphysema, pulmonary fibrosis, or both. However, it is unclear whether this dysfunction leads to higher rates of radiation induced lung toxicity (RILT). We sought to assess whether baseline or change in baseline to mid-treatment spirometry based pulmonary function testing (PFTs) and/or pretreatment CT graded emphysema (EM) or pulmonary fibrosis (PF) scores were associated with RILT.

Materials/Methods: We performed an institutional review board approved analysis of patients with localized NSCLC treated with non-SBRT external beam RT on 4 consecutive prospective trials from 2004-2013. The primary outcome was grade ≥2 RILT including pneumonitis and fibrosis. PFTs consisted of FEV1, FVC, FEV1/FVC, and DLCO. For baseline CT EM and PF grading, the lungs were divided into 6 zones. EM was scored from 0-4 and PF from 0-3, using existing clinical scoring schemes. Global EM and PF scores were created by summing the respective scores in each of the 6 defined zones. Regional tumor EM and PF scores were created using the highest score for each in the lung zone containing gross target volume. Multivariable analysis was performed with Cox-proportional hazard models.

Results: 96 patients were available for analysis. 78% of patients received concurrent chemotherapy. Mean mean lung dose (MLD) was 14 Gy (2 Gy equivalent). Median FEV1/FVC and DLCO were 64 (interquartile range [IQR] 52-71) and 60 (IQR 49-74), respectively. Median global and regional tumor CT based EM scores were 6 (range 0-20) and 1 (range 0-3). Median global and regional tumor CT based PF scores were 0 (range 0-8) and 0 (range 0-3). 20 patients developed RILT with a 20 month freedom from RILT of 75%. 51 patients had mid treatment PFTs. PFTs changed minimally from baseline to mid-treatment, with no difference in changes when comparing patients with and without RILT. PFTs were not associated with RILT (all p >0.1). Global and regional tumor baseline CT EM and PF scores were individually associated with RILT when controlling for patient age, MLD, smoking status, and receipt of chemotherapy (all p<0.05). When controlling for EM and PF scores jointly, global scores no longer remained statistically significant (p>0.05), whereas regional tumor scores did (EM HR: 1.7, 95% CI: 1.1-2.8, p=0.03, PF HR: 2.2, 95% CI: 1.1-4.4, p=0.04).

Conclusion: The severity of emphysema and fibrosis adjacent to tumor on pre-treatment CT imaging is associated with development of RILT, whereas global CT scores and PFTs are not. These findings suggest that peri-tumoral regional lung function and anatomy predict for risk of grade ≥2 RILT. This easily obtainable radiographic information combined with other clinical/dosimetric factors can help guide individualization of radiation treatment delivery.

Author Disclosure: W.C. Jackson: None. P.S. Boonstra: None. D.R. Owen: None. P. Jain: None. G. Sun: None. D. Arenberg: None. G.P. Kalemkerian: None. F.(. Kong: Research Grant; Varian, NCI/NIH. Founding President and Board of Director; Sino-American Network for Therapeutic Radiation On. President 2015; American Association of Women Radiologists (AAWR). President 2012-2013; Association for Chinese Professors. Founding Board Member; Sino-American Network for Therapeutic Radiology. J.A. Hayman: Research Grant; Blue Cross Blue Shield of Michigan. T.S. Lawrence: royalties; Lippincott, Williams and Wilkins. Honoraria; Massachusetts General Hospital, Pfizer Oncology Innovation Summit, Sidney Kimmel Foundation for Cancer Research. Consultant; Pfizer Oncology Innovation Summit. Advisory Board; ASTRO Radiation Oncology Institute, Dana Farber Cancer Institute, Massachusetts General Hospital, Sidney Kimmel Compreh Cancer Ctr at Johns Hopkins, Sidney Kimmel Foundation for Cancer Research, St. Jude Children's Research Hospital, University of Wisconsin Comprehensive Cancer Ctr. Travel Expenses; AACR, ASTRO Radiation Oncology Institute, Dana Farber Cancer Institute, Lippincott, Williams and Wilkins, Massachusetts General Hospital, Pfizer Oncology Innovation Summit, RSNA, Sidney Kimmel Compreh Cancer Ctr at Johns Hopkins, Sidney Kimmel Foundation for Cancer Research, St. Jude Children's Research Hospital, University of Wisconsin Comprehensive Cancer Ctr. Patent/License Fees/Copyright; Pi Squared Therapeutics. Editor, Cancer Discovery; AACR. Member, Editorial Advisory Board, Cancer Today; AACR. Senior Editor, Cancer Research; AACR. Member, External Advisory Board for Lung SPORE; Dana Farber Cancer Institute. Co-Editor of Principles and Practices of Oncology; Lippincott, Williams and Wilkins. Member, NCI Board of Scientific Advisors; NCI - BSA. President; ROI. Member, External Advisory Board for the Cancer Ctr; Sidney Kimmel CCC at Johns Hopkins University. Member of the Medical Advisory Board; Sidney Kimmel Foundation for Cancer Research. Vice-Chair, St. Jude Scientific Advisory Board; St. Jude Children's Research Hospital. Member, V Foundation Scientific Advisory Board; V Foundation for Cancer Research. R.K. Ten Haken: Research Grant; NIH-NCI. Honoraria; University of Copenhagen. Travel Expenses; Varian Medical Systems Inc, University of Copenhagen. M.M. Matuszak: Employee; William Beaumont Hospital. S. Jolly: None.

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TU_29_3602 - Pretreatment CT Based Emphysema and Fibrosis Scoring of Peri-Tumoral Lung Parenchyma Predicts Risk of Radiation Induced Lung Toxicity



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