Abstract
Background: Disparities in resection rates and survival for patients with lung cancer are well-documented. It is suggested that lower survival rates among blacks are largely due to lower rates of resection and that equivalent outcomes are possible for blacks and whites with similar treatment. The objective of this study was to determine the extent of racial variation in patterns of initial therapy and treatment-specific outcomes.
Methods: We conducted a retrospective analysis of a national cohort of patients in the Veterans Affairs Central Cancer Registry diagnosed with Stage I/II non-small cell lung cancer (NSCLC) between 2001 and 2008. Descriptive and chi-square statistics were used to compare the prevalence of treatment and outcomes in Whites and Blacks. Cox proportional hazards models were used to estimate hazard ratios (HR) with 95% confidence intervals (95%CI).
Results: Among 14,445 patients with stage I/II NSCLC, 57% received surgery (17% diagnosed at surgery, 40% received surgery within 6 months after diagnosis), 22% received radiation therapy and/or chemotherapy, and 21% had no treatment. The proportion of blacks and whites diagnosed at surgery was similar (both 17%), whereas the proportion of blacks receiving surgery post-diagnosis (34%) was significantly less than whites (41%) (p<0.0001). There was no racial difference in receipt of radiation therapy or chemotherapy among those who did not have surgery; however, blacks were more likely than whites to have no treatment (25% vs. 20%, p<0.0001). Among all surgical patients, rates of lobectomy, wedge resection, and pneumonectomy did not vary significantly by race, yet the frequency of other types of resection (e.g. segmentectomy) was greater among blacks (6%) than whites (4%) (p=0.0005). Approximately 17% of surgery patients had neoadjuvant or adjuvant therapy, which was similar in both race groups. Whites had a significantly greater prevalence of 90-day post-operative mortality than blacks (6% vs 3%, p<0.0001). Among all patients, blacks and whites had equivalent rates of 4-year survival. The adjusted HR for blacks compared to whites was 0.97 (95%CI 0.92-1.02) in the total population. Adjusted HRs also indicated no association between race and survival in each of the following treatment subgroups: diagnosed at surgery, surgery after diagnosis, and no treatment. The type of resection and the addition of neoadjuvant or adjuvant therapy did not impact the race-survival association. Black race correlated with better survival among patients receiving nonsurgical treatment (HR: 0.84, 95%CI 0.75-0.93, p=0.0007).
Conclusion: Racial differences in receipt of surgery are limited to patients diagnosed prior to surgical treatment, which emphasizes the need to understand the impact of knowledge of the diagnosis on decision-making regarding surgery. The lower post-operative mortality observed among blacks is partially explained by the greater frequency of less extensive resection among blacks. Equal treatment generally confers similar outcomes in blacks and whites, and despite lower rates of post-diagnostic surgery, there were no racial differences in overall survival. There remains the need to identify factors that affect the association between race and short vs long-term clinical and patient-reported outcomes.
Note: This abstract was withdrawn after the Proceedings was printed and was not presented at the conference.
Citation Format: Christina D. Williams. Prevalence and effectiveness of treatment patterns for early-stage lung cancer. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr A91. doi:10.1158/1538-7755.DISP13-A91
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