Lung Cancer

PD 18 - Lung 5 - Poster Discussion - SBRT

1156 - Baseline COPD in Lung Cancer Patients is Not Associated with Increased Radiation Pneumonitis or Increased Pulmonary Function Decline Following Lung Radiation Therapy

Wednesday, October 24
1:48 PM - 1:54 PM
Location: Room 217 C/D

Baseline COPD in Lung Cancer Patients is Not Associated with Increased Radiation Pneumonitis or Increased Pulmonary Function Decline Following Lung Radiation Therapy
A. C. Ferro, P. Han, T. R. McNutt, R. Voong, L. Chang, M. R. Bowers, P. Lakshminarayanan, K. Ford, E. Honig, E. Desmarais, and R. K. Hales; Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD

Purpose/Objective(s): The association between COPD and pulmonary toxicity following thoracic radiation is not well characterized. Herein, we review PFT changes following intensity-modulated radiation therapy (IMRT). Additionally, we review toxicity data from patients treated with IMRT to determine if baseline COPD is associated with increased post-treatment pulmonary toxicity. Materials/Methods: Medical records were reviewed for lung cancer patients treated with IMRT between 05/2008 and 10/2015. Patient characteristics, treatment details, and subacute and late toxicities (RP and PFTs) were recorded. COPD was defined as FEV1/FVC < 0.7. CTCAE grade ≥ 2 RP was defined as requiring steroids within 12 months following radiation, unrelated to medical comorbidities. Post-treatment PFTs were normalized to baseline PFTs and the relative declines were reported for the subacute time frame (<6 months) and late setting (>12 months). Correlations of continuous and categorical variables were assessed using Student’s t-test and chi-squared test, respectively. Results: Baseline and post-treatment PFTs were available for 188 patients. Baseline COPD was present in 53% of patients. CTCAE Grade ≥ 2 RP toxicity was recorded in 10.6% of patients. PFT analysis of the cohort prior to stratification by COPD status showed a post-treatment DLCO decrease during all time intervals, but there was gradual improvement with increased time (19% vs 6%, for 1-3 months vs 24-36 months post-treatment, respectively). Post-treatment FEV1 and FVC initially declined, but then recovered to baseline. The maximum declines in FEV1 (6%) and FVC (4%) occurred 1-3 months post-treatment. Table 1 displays post-treatment percent predicted DLCO, FEV1, and FVC stratified by baseline COPD status. Patients with COPD had decreased baseline DLCO and FEV1 compared to patients without COPD. Patients without baseline COPD had greater relative reductions in FEV1 and FVC in the subacute setting compared with COPD patients. There were no PFT correlations >12 months post-treatment. Baseline COPD did not predict for the development of CTCAE Grade ≥ 2 RP (11% vs 10.2%, COPD vs non-COPD) (p= 0.86).

Conclusion: Post-treatment DLCO decreased during all time intervals, but showed gradual improvement in our cohort independent of COPD status. Post-treatment FEV1 and FVC declined, but then recovered to baseline. COPD was not associated with relative declines in PFTs or increased CTCAE Grade ≥ 2 RP. COPD appears protective against FEV1 and FVC reduction in the subacute setting, but these trends do not persist in the chronic phase.
Variable

Baseline

± SD)

p

<6 months post RT ± SD)

p

>12 months post RT

± SD)

p

DLCO COPD No COPD ±22 ±23 <0.001 COPD No COPD ± 3% ±4% NS COPD No COPD ± 4% ±4% NS
FEV1 COPD No COPD ±20 ±21 <0.001 COPD No COPD ±3% ± 3% <0.001 COPD No COPD ±4% ± 4% NS
FVC COPD No COPD ±20 ±21 NS COPD No COPD ±2% ± 3% 0.07 COPD No COPD ±3% ± 5% NS

Author Disclosure: A.C. Ferro: None. P. Han: None. T.R. McNutt: Research Grant; Elekta Oncology Systems, Philips Radiation Oncology Systems, Toshiba. Patent/License Fees/Copyright; Accuray-Tomotherapy, Sun Nuclear. President Elect; AAPM-MAC. R. Voong: Honoraria; Lung Cancer Research Foundation, Radiation Oncology Institute, ASCO. L. Chang: None. M.R. Bowers: None. P. Lakshminarayanan: None. K. Ford: None. E. Desmarais: None. R.K. Hales: Consultant; AstraZeneca.

Adam Ferro, MD, MS

Disclosure:
Employment
Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine: Resident: Employee

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