Trends in Regimen for Palliative Radiation Therapy of Bone Metastases in Patients with Non-Small Cell Lung Cancer

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Non-small cell lung cancer (NSCLC) is among one of the most common solid malignancies associated with bone metastases (BM). Palliative radiation therapy (RT) is the standard of care to alleviate symptoms associated with BM. Multiple randomized trials have shown equivalent pain relief with single fraction or short-course RT compared to longer palliative RT courses. In this study, we reviewed the NCDB to report on trends of short- and long-course palliative RT for BM in patients with NSCLC. There were 10,271 patients with NSCLC and BM treated with palliative RT between 2004 and 2014 were identified in the NCDB. Fractionation scheme was defined as short-course [(SC-RT): 8 Gy in 1 fractions and 20 Gy in 5 fractions] versus long-course [(LC-RT): 30 Gy in 10 fractions and 37.5 Gy in 15 fractions]. Patients coded with metastases to the ‘spinal cord’ were excluded. Trends in use of SC-RT versus LC-RT in the years 2004-2014 were analyzed with Chi Square test and ANOVA. Patient demographics and disease characteristics were correlated with fractionation scheme using multivariable logistic regression. A total of 1933 (18.8%) patients were included in the SC-RT group and 8338 (81.2%) patients in the LC-RT group. Sites of BM were spine (57.2%), extremity (13.9%), hip/pelvis (21.9%) ribs (6.1%), and skull (0.9%). The use of SC-RT has increased from 12.2% in 2004 to 27.6% in 2014 (p<0.0001). Factors associated with increased use of SC-RT included: academic treatment facility [Odds ratio (OR): 0.58 (95% CI, 0.52-0.65); p<0.0001], living > 20 miles from treatment facility [OR: 0.69 (95% CI, 0.55-0.87); p=0.002], treatment to the rib [OR: 0.68 (95% CI, 0.55-0.84); p<0.0001], treatment in the year 2010 [OR: 0.63 (95% CI, 0.46-0.85); p=0.003], treatment in the year 2011 [OR: 0.55 (95% CI, 0.41-0.74); p<0.0001], treatment in the year 2012 [OR: 0.55 (95% CI, 0.41-0.74); p<0.0001], treatment in the year 2013 [OR: 0.43 (95% CI, 0.32-0.57); p<0.0001], and treatment in 2014 [OR: 0.37 (95% CI, 0.28-0.49); p<0.0001]. Increasing age trended toward association of SC-RT [OR: 0.99 (95% CI, 0.99-1.00); p=0.071] though did not reach statistical significance. Factors associated with increased utilization of LC-RT included living <5 miles to treatment facility [OR: 1.15 (95% CI, 1.01-1.30); p=0.029], treatment to the hip/pelvis [OR: 1.43 (95% CI, 1.21-1.67); p<0.0001], and treatment to the spine [OR: 2.51 (95% CI, 2.17-2.90); p<0.0001]. Our analysis reveals that LC-RT remains the most common fractionation scheme for palliative treatment of BM in NSCLC patients. Use of palliative short-course RT is increasing, and has more than doubled between 2004 and 2014. SC-RT is more common in academic facilities and for patients who live a large distance from a treatment facility. Although randomized evidence supports equivalent pain relief with SC-RT, its use remains under-utilized and requires further advocacy for palliative treatment of BM.