Curative-intent radiotherapy outcomes in NSCLC patients with severe/very severe COPD & lung fibrosis

Abstract

Purpose or Objective Management of inoperable non-small cell lung cancer (NSCLC) patients with severe chronic obstructive pulmonary disease (COPD) and lung fibrosis is complex. We investigated outcomes of curative-intent thoracic radiotherapy in these patients. Material and Methods A retrospective real world dataset of 587 NSCLC patients with COPD and 34 with lung fibrosis treated with curativeintent thoracic radiotherapy at The Christie NHS Foundation Trust (Manchester, UK) from January 2015 to December 2016 were analysed. COPD severity was graded using Global Initiative for Chronic Obstructive Lung Disease classification (GOLD I-IV), dependent on forced expiratory volume in 1 second (FEV1). The primary endpoint was overall-survival (OS). The longitudinal use of oxygen therapy and Medical Research Council (MRC) dyspnoea scores were evaluated in a patient subset. Demographic and clinical characteristics, baseline lung function and radiotherapy and dosimetric lung parameters were evaluated for association with OS. Results The characteristics for the whole cohort are shown in table 1. 148 (25%) COPD patients received stereotactic ablative body radiotherapy (SABR). Median OS was 20 months (95% CI: 17-21) for GOLD I (mild COPD; n=194), 19 months (95% CI 17-21) for GOLD II (moderate COPD; n=255) and 20 months for GOLD III/ IV (severe and very severe COPD; n=138) patients, respectively (fig1A). FEV1 and GOLD category did not correlate with OS (p≥0.05). Median OS was significantly shorter for patients with lung fibrosis (12 months, 95% CI: 4-18) compared to patients without lung fibrosis (21 months, 95% CI: 19-23); p<0.001 (fig1B). Treatment type (fractionated radiotherapy worse compared to SABR), larger tumour volume, higher dosimetric lung parameters (mean dose, V20 and V5), advanced tumour stage and squamous histology all correlated with poor OS (p<0.05). MRC dyspnoea scores and oxygen therapy data were available in 21 (62%) and 14 (41%) fibrosis patients and 92 (67%) and 40 (30%) GOLD III/ IV COPD patients, respectively. MRC dyspnoea scores were not significantly different before and after radiotherapy in fibrosis and GOLD III/ IV patients (p≥0.05). Oxygen therapy increased after radiotherapy in GOLD III/ IV patients (n=12 before vs n=28 after) and in fibrosis patients (n=4 before vs n=10 after). NSCLC patients with lung fibrosis have poor OS after curative-intent thoracic radiotherapy. FEV1 and COPD severity scores are not prognosticators and should not be considered absolute contraindications for curative-intent thoracic radiotherapy in NSCLC patients. Prospective studies with functional and quality of life assessments are needed to further refine radiotherapy treatment in these patients.