Utilization and impact of adjuvant chemotherapy (AC) in surgically resected stages I-III non-small cell lung cancer (NSCLC).

Abstract

7538 Background: Clinical trials demonstrating improved survival with AC for stages I-III NSCLC are limited in their applicability to broader populations. We sought to describe the pattern of AC use and its correlation with survival in the population-based VA system. Methods: We conducted a retrospective analysis of pts with stages I-III NSCLC in the VA Central Cancer Registry. Descriptive statistics were used to examine patterns of AC use over an 8 yr period and to obtain survival rates associated with use of AC. Chi-square was used to compare distributions. Results: Among 28,173 pts with stages I-III NSCLC in 2001-2008, 10,043 had surgical resection. The proportion receiving AC was 9% (stage I), 34% (II), and 40% (III). Receipt of AC increased for each stage, with the greatest increase observed in stage II (2001-03: 12%; 2004-05: 41%; 2006-08: 50%). About 90% received a platinum agent; among these carboplatin was most common (77%) but by 2008 43% received cisplatin. For stages II and III in 2001-2003, the 3-year survival rate was similar irrespective of AC use. In latter time periods, survival rates were significantly higher for stage II AC pts (2004-2005: 53 vs 43%, p=0.03; 2006-2008: 58 vs 46%, p=0.001). Stage III AC pt diagnosed in 2006-2008 had a higher 3-yr survival (52 vs 36%, p<0.001). For all stages and years combined, use of cisplatin yielded a better 3-yr survival rate compared to carboplatin (62% vs 55%; p=0.01). 3-yr survival for stage I, II, and III, regardless of AC, increased over time (stage I: 60, 64, and 69%; stage II: 44, 47, 52%; stage III: 33, 40, and 44%). The fraction of lung cancer pts diagnosed at each stage during the 3 time periods was not significantly different. Conclusions: This retrospective study suggests a significant increase in use of AC for NSCLC in the VA, though half of surgically treated pts with stage II and III did not receive AC in 2006-2008. By univariate analysis, AC use is associated with a significantly better 3-yr survival for resected stage II and III NSCLC and the stage-specific 3-year survival for all pts improved over time in association with increasing use of AC. Cisplatin is associated with better survival compared to carboplatin. Multivariate analysis is planned.