Background: Radiation therapy (RT) for lung cancer is a standard of care. Radiation exposure to normal lung tissue can cause loss of function due to pneumonitis and fibrosis. We evaluated subjectively and objectively with pulmonary function tests (PFT) for toxicity following RT.
Objective: The purpose of our retrospective study was to correlate post radiation PFT changes and symptoms.
Methods: We studied retrospectively 18 patients with lung cancer treated at the Jackson VAMC between 2014 and 2016. All patients had pretreatment and posttreatment PFTs. Symptoms of dyspnea were graded using the Common Terminology Criteria for Adverse Events (CTCAE).
Results: Sixteen received SBRT; (15 with 50 Gy in 5 fractions; one 48 Gy in 4 fractions); one 60 Gy in 6 weeks and one 45 Gy in 30 bid fractions. Sites of treatment included 13 (72%) upper lobe, 2 (11%) right middle lobe and 3 (17%) lower lobe. The median drop in FEV1 posttreatment was 0.15. While 8 (44%) patients had grade I/II dyspnea prior to treatment, 14 (78%) patients had the same after treatment. Only 1 patient who received both SBRT to LUL and Conventional XRT to the mediastinum developed grade II dyspnea. His FEV1 dropped 37% or 0.37 from baseline. Symptomatically 11 (61%) had no increased dyspnea with a median FEV1 drop of 3% or 0.06 from baseline; while 7 (39%) patients had worsening of dyspnea after treatment with a median drop of 0.23 (11%) from baseline in FEV1. Patients treated in the middle and lower lobes had a median FEV1 drop of 0.43 from baseline There was no significant median change (+0.04) when treating the upper lobe. 38% of patients who had an upper lobe treated complained of worsening dyspnea, while 66% of patients with lower lobe treated reported worsening dyspnea.
Conclusions: After definitive XRT, 39% of patients had worsening in symptoms with a median drop of 11% in the FEV1, compared to only a 3% drop in FEV1 in patients who did not report a worsening of symptoms. Patients with lower lobe tumors had greater PFT changes with worsening dyspnea.
