Survival Outcomes With Thoracic Radiotherapy in Extensive-Stage Small-Cell Lung Cancer: A Propensity Score-Matched Analysis of the National Cancer Database

• Published in: Clinical lung cancer 2019-11, Vol.20 (6), p.484-493.e6
• Main Authors: Tian, Sibo, Zhang, Xinyan, Jiang, Renjian, Pillai, Rathi N., Owonikoko, Taofeek K., Steuer, Conor E., Saba, Nabil F., Pakkala, Suchita, Patel, Pretesh R., Belani, Chandra P., Khuri, Fadlo R., Curran, Walter J., Ramalingam, Suresh S., Behera, Madhusmita, Higgins, Kristin A.
• Format: Article
• Language: English
• Subjects: Aged; Chemoradiation; Chemoradiotherapy - methods; Chemotherapy; Consolidative radiotherapy; Databases, Factual; Female; Follow-Up Studies; Humans; Lung Neoplasms - mortality; Lung Neoplasms - pathology; Lung Neoplasms - therapy; Male; Middle Aged; Neoplasm Staging; Propensity Score; Radiotherapy - methods; Small Cell Lung Carcinoma - mortality; Small Cell Lung Carcinoma - pathology; Small Cell Lung Carcinoma - therapy; Small-cell lung carcinoma; Standard of Care; Survival Analysis; Thoracic radiation therapy; Thorax - diagnostic imaging; Treatment Outcome
• ISSN: 1525-7304; 1938-0690
• DOI: 10.1016/j.cllc.2019.06.014

The prognosis of patients with extensive-stage small-cell lung carcinoma (ES-SCLC) is poor. The benefit of consolidative thoracic radiation therapy (TRT) in ES-SCLC has been inconclusive, and its use inconsistent. The objective of this study was to evaluate overall survival (OS) of ES-SCLC patients treated with chemotherapy (CT) with or without TRT using an administrative database approach. The National Cancer Database was queried to identify patients with ES-SCLC diagnosed between 2010 and 2014. Those with brain metastases, those who received radiotherapy before CT, or radiotherapy outside the thorax, were excluded. Propensity score-matching (PSM) was used to compare OS of patients treated with CT and TRT with those who received CT alone. Patients who received >10 radiotherapy fractions were also compared with those who received 10 or fewer. We included 14,367 patients in the primary analysis; 12,019 received CT alone, and 2348 received CT with TRT. In multivariate analysis, CT was associated with an increased risk of death relative to CT with TRT (hazard ratio [HR], 1.74 [95% confidence interval (CI), 1.64-1.84]; log-rank P < .001), which remained significant with PSM. Median OS was 12.1 versus 8.2 months (CT with TRT vs. CT); 12-month OS was 50.5% versus 28.5%, and 5-year OS 7.6% versus 2.0% (HR, 1.80 [95% CI, 1.67-1.95], HR P < .001). Of 3099 patients who received TRT, >10 radiotherapy fractions was associated with superior OS (HR, 1.70 [95% CI, 1.49-1.95], log-rank P < .001); this finding remained significant with PSM. Use of TRT after CT in ES-SCLC patients was associated with long-term survival; its use should be considered in addition to standard of care CT. The role of consolidative thoracic radiotherapy is unclear in extensive-stage small-cell lung carcinoma, for which chemotherapy is standard. We aimed to evaluate its effect on survival using a large national database using propensity-matching methods. On the basis of a cohort of >14,000 patients, we found its use in addition to chemotherapy was associated with a significant improvement in survival.