Lung Cancer

PD 18 - Lung 5 - Poster Discussion - SBRT

1153 - Active Smoking Is Not Associated with Increased Radiation-Induced Toxicity in Locally Advanced Lung Cancer Patients

Wednesday, October 24
1:30 PM - 1:36 PM
Location: Room 217 C/D

Active Smoking Is Not Associated with Increased Radiation-Induced Toxicity in Locally Advanced Lung Cancer Patients
A. M. Laucis1, Y. Sun2, M. Schipper1,2, C. Maurino1, A. Saripalli1, M. McFarlane1, D. Arenberg3, R. K. Ten Haken1, F. M. Kong4, M. M. Matuszak1, D. E. Spratt1, L. J. Pierce5, J. A. Hayman5, P. A. Paximadis6, and S. Jolly5; 1Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 2Department of Biostatistics, University of Michigan, Ann Arbor, MI, 3Department of Internal Medicine, Division of Pulmonary & Critical Care Medicine, University of Michigan, Ann Arbor, MI, 4Department of Radiation Oncology, Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, 5Michigan Medicine, Ann Arbor, MI, 6Lakeland Radiation Oncology, St. Joseph, MI

Purpose/Objective(s): To limit morbidity from thoracotomy and improve healing, surgeons often will not operate on active smokers. Active smoking during radiation therapy is associated with worse tumor control outcomes. However, the relationship between smoking and toxicity of thoracic radiation treatment (TRT) is not well known. We conducted this study to determine whether smoking increases morbidity of TRT in lung cancer patients.

Materials/Methods: Two large prospective databases were analyzed, including from 4 institutional investigator initiated trials (IIT) and a large multicenter statewide quality consortium. Smoking status was defined as active smokers versus former/never smokers. Logistic regression was used to determine the relationship between smoking and esophagitis, pneumonitis, and cardiac events. Adjustments were made for PTV volume, concurrent chemotherapy, and radiation dose to organs at risk. Due to heterogeneity in consortium data follow-up time, weighting variables were used to model pneumonitis outcome.

Results: A total of 1248 patients were analyzed in the IIT and consortium cohorts (172 and 1076, respectively), with mean age of 66 and 67 years, PTV volume of 421 and 359 mL, concurrent chemotherapy rates of 69.8% and 83.3%, active smoking rates of 41.9% and 40.7%, total incidence of grade≥2 pneumonitis of 17.1% and 9.2%, and grade≥2 esophagitis rates of 41.4% and 58.7%, respectively, for the IIT and consortium cohorts. There was no evidence supporting a significant effect of smoking on any toxicity outcome (Table 1). However, in both cohorts there was a significant relationship between esophagitis and two variables (concurrent chemotherapy use and mean esophageal dose, p≤0.05) and a trend towards significance between mean lung dose and pneumonitis in the IIT cohort (p=0.05). There was no significant relationship between any variable and cardiac events in the IIT cohort; however, median follow-up was limited to 25.8 months.

Conclusion: As an independent variable, active smoking is not associated with higher rates of radiation-associated esophagitis, pneumonitis, or cardiac events in lung cancer patients. While smoking cessation remains imperative to improve local control and survival outcomes in lung cancer, our study is the largest prospective data analysis of locally advanced lung cancer patients to show no increase in TRT-induced morbidity in smokers.     Table 1: Effect of Clinical Variables on Radiation-Induced Toxicities

 

Esophagitis

Pneumonitis

Cardiac Events

 

Consortium

IIT

Consortium

IIT

IIT

Clinical variable

Odds ratio (OR)

p-value (p)

OR

p

OR

p

OR

p

OR

p

PTV volume

0.996

0.87

0.978

0.75

1.06

0.17

1.01

0.90

0.967

0.71

Concurrent Chemo

2.48

<0.0001

8.64

0.05

1.08

0.87

0.807

0.79

6.24

0.1

Mean Esophageal Dose

1.07

<0.0001

1.06

0.02

-

-

-

-

-

-

Mean Lung Dose

-

-

-

-

1.07

0.1

1.17

0.05

-

-

Mean Heart Dose

-

-

-

-

-

-

-

-

1.03

0.29

Active Smoker

1.19

0.12

1.46

0.35

0.827

0.49

0.793

0.65

0.954

0.93

 

Author Disclosure: A.M. Laucis: None. Y. Sun: None. C. Maurino: None. A. Saripalli: None. D. Arenberg: Employee; Chapel Dermatology. Research Grant; Michigan Department of Health. Committee Member; IASLC. Guidelines revision executive committee; American College of Chest Physicians. R.K. Ten Haken: Travel Expenses; Varian Medical Systems. 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. M.M. Matuszak: Employee; William Beaumont Hospital. L.J. Pierce: Royalty; UpToDate. J.A. Hayman: Research Grant; Blue Cross Blue Shield of Michigan. P.A. Paximadis: None. S. Jolly: None.

Anna Laucis, MD, MPhil

Disclosure:
No relationships to disclose.

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