Disparities in Survival After Immunotherapy

Survival outcomes of NSCLC are worse for Black patients than for White patients, but it is unclear if the disparities persist when access to immunotherapy is equal, said Anjali Gupta, a student at Duke University in Durham, North Carolina, during her presentation at the AACR 2021 Virtual Cancer Health Disparities Conference.2

Ms Gupta presented a study of racial differences in survival among patients with advanced NSCLC who received immunotherapy.

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The study included data on 3068 patients from the National Cancer Database (NCDB). Patients were diagnosed with stage III-IV NSCLC during 2015-2016, had received immunotherapy, and had complete data on sociodemographic, clinical, and healthcare access covariates. 

The cohort included 385 non-Hispanic Black patients, 2462 non-Hispanic White patients, and 221 patients who self-identified as another race.

Kaplan-Meier curves showed a higher probability of survival in non-Hispanic Black patients than in non-Hispanic White patients (log rank P <.0001).

Cox proportional hazards models demonstrated similar results. In a model adjusted for age, sex, income, insurance, education, and facility type, the all-cause mortality was 15% lower for Black patients than for White patients (hazard ratio [HR], 0.85; 95% CI, 0.74-0.98). 

The same magnitude and direction of difference was noted in a model additionally adjusted for Charlson-Deyo morbidity score, histology, site of metastasis, and treatment received (HR, 0.85; 95% CI, 0.74-0.98).

Ms Gupta concluded that racial disparities in outcome are mitigated by equal treatment. However, she acknowledged that this study had limitations.

First, the Charlson-Deyo Comorbidity Index tabulates the number of concurrent medical conditions without adjusting for the severity of those conditions. It is possible that the Black patients were healthier than the White patients in this study.

Another limitation is that the NCDB lacks information about smoking status. If Black patients in this sample were more likely than White patients to be smokers, the Black patients may have responded more robustly to immune checkpoint inhibitor therapy due to a high tumor mutation burden.

Lastly, the NCDB does not include data on specific immunotherapies used, PD-L1 expression, or cause of death. It is conceivable that there were imbalances in those factors.

Take-Away Messages

For many reasons, 5-year relative survival rates are lower for Black patients than for White patients with lung cancer.3 Disparities in access to screening in high-risk individuals, delays in diagnosis, failure to use guideline-driven therapy, and suboptimal enrollment on clinical trials are among the factors involved.

Dr Richmond and colleagues remind us that the burden of advanced stage at diagnosis differentially affects geographically disadvantaged patients, including Black Americans. A 2020 study showed no evidence of a shift to earlier diagnosis from 2001 to 2016, suggesting little impact of lung cancer screening on population-based mortality trends.4

In contrast, targeted therapy, including immunotherapy, has contributed to a decline in lung cancer mortality.3 The 2-year relative survival rate for lung cancer increased from 30% in 2009-2010 to 36% in 2015-2016. Progress was confined to the 80% of individuals diagnosed with NSCLC.

Unfortunately, declines in mortality are not universal, even for patients with NSCLC. Ms Gupta’s presentation suggested that the discrepancies in outcome were not related to inherent differences in tumor biology and could be improved by application of guideline-driven treatment even in patients with advanced disease.

As intuitive and reinforcing as the conclusions of Ms Gupta and Dr Richmond’s studies are, the methodology employed in both — database surveys with statistical adjustment for clinical and demographic covariates — must be regarded as hypothesis-generating. 

The conclusions should be replicated in additional population-based studies and, to the extent possible, randomized clinical trials.

In the meantime, the research presented at the AACR 2021 Virtual Cancer Health Disparities Conference supports policies that provide patients with equal access to state-of-the-art care as a strategy to improve outcomes for Americans with lung cancer.

Read more of Cancer Therapy Advisor’s coverage of the AACR 2021 Virtual Conference on Cancer Health Disparities by visiting the conference page.

References

  1. Richmond J, Hollister M, Milder CM, et al. Examining racial disparities in lung cancer stage of diagnosis among low income adults living in the southeastern U.S. Presented at: AACR 2021 Virtual Cancer Health Disparities; October 6-8, 2021. Abstract PO-236.
  2. Gupta A, Akinyemigu T. Racial differences in survival among advanced-stage non-small cell lung cancer patients who received immunotherapy: An analysis of the U.S. National Cancer Database (NCDB). Presented at: AACR 2021 Virtual Cancer Health Disparities; October 6-8, 2021. Abstract PO-107.
  3. Siegel RL, Miller KD, Fuchs HE, Jemal A. Cancer Statistics, 2021. CA Cancer J Clin. 2021;71(1):7-33. doi: 10.3322/caac.21654
  4. Howlader N, Forjaz G, Mooradian MJ, et al. The effect of advances in lung-cancer treatment on population mortality. N Engl J Med. 2020;383(7):640-649. doi:10.1056/NEJMoa1916623

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AACR DIsparities 2021 Lung Cancer