Long-term survival trends in patients with unresectable stage III non-small cell lung cancer receiving chemotherapy and radiation therapy: a SEER cancer registry analysis

Background To evaluate the value of new therapies for non-small cell lung cancer (NSCLC), it is necessary to understand overall survival (OS) rates associated with previous standard therapies and how these rates have evolved over time. Methods We retrospectively analyzed data from patients enrolled in the Surveillance, Epidemiology, and End Results (SEER) cancer registry. Adults with unresectable, stage III NSCLC treated with chemoradiotherapy were grouped by diagnosis year (2000-2002; 2003-2005; 2006-2008; 2009-2011; 2012-2013). The primary endpoint was OS (data cut-off, December 31, 2014), estimated using the Kaplan-Meier estimator. Temporal survival-trend significance was tested using a two-sided log-rank trend test. Results Of 12,865 eligible patients, 59.1% were male, 59.9% had stage IIIB disease, and 62.7% had non-squamous histology. Median age at diagnosis was 67 years. Overall, 10,899 (84.7%) patients died and 1966 (15.3%) were censored/lost to follow-up. Median follow-up (95% confidence interval [CI]) was 80 (77-82) months; median OS (95% CI) was 15 (15-16) months; 1- and 3-year survival probabilities (95% CI) were 57.7% (56.9-58.6) and 24.1% (23.3-24.8), respectively. Stratification by diagnosis year showed consistent improvements in survival over time (p < 0.0001 for trend). Median OS was 12, 14, 15, 18, and 19 months in successive cohorts. Conclusions OS in patients diagnosed with unresectable, stage III NSCLC between 2003 and 2013 was consistent with that from clinical studies of sequential/concurrent chemoradiotherapy. Despite improvement over time, median OS was < 2 years and mortality remained high during the first year post-diagnosis.