Study Finds Racial and Ethnic Disparities in Treatment for Advanced Lung and Other Cancers Among Medicare Beneficiaries

Racial and ethnic disparities persist in the treatment of metastatic cancer among Medicare fee-for-service beneficiaries, with significant differences in receipt of systemic therapy for lung and other common cancers, according to research published August 27 in the Journal of Clinical Oncology. The analysis was led by John K. Lin, M.D., M.S.H.P., of the Department of Health Services Research at The University of Texas MD Anderson Cancer Center.

Disparities in cancer outcomes have been well documented, with Black patients facing worse survival and lower utilization of newer therapies compared with White patients. Inequities occur at multiple steps in what is known as the cancer treatment cascade, beginning with diagnosis and oncology referral and extending through systemic therapy and survival. Questions remain as to where along this cascade the greatest disparities arise and which patient groups are most at risk of undertreatment.

In the new study, researchers used the SEER-Medicare-linked database to examine treatment patterns and survival outcomes for Medicare beneficiaries diagnosed between 2016 and 2020. The study included 18,652 White, 1,898 Black, and 1,465 Hispanic patients with metastatic lung, breast, colorectal, or prostate cancers.

Researchers evaluated the “treatment cascade,” from diagnosis through oncology consultation, receipt of systemic therapy, and survival outcomes. Within two months of diagnosis, 78% of patients were alive and 87% had seen an oncologist, with no consistent racial or ethnic disparities at these steps.

Disparities emerged in receipt of systemic therapy, particularly in lung cancer. Among patients with metastatic non-small cell lung cancer, 26% of Black patients, 37% of Hispanic patients, and 39% of White patients received systemic therapy. Across all cancer types studied, fewer than 35% of patients received guideline-directed systemic therapy.

Significant differences were also observed in other cancers. For example, for metastatic breast cancer, systemic therapy was received by 59% of Black patients, 60% of Hispanic patients, and 68% of White patients. In prostate cancer, 56% of Black patients received therapy, compared with 76% of Hispanic patients and 77% of White patients. For colorectal cancer, rates were 23%, 31%, and 34%, respectively.

After restricting the analysis to patients who did receive systemic therapy within two months of diagnosis, overall survival disparities were no longer statistically significant. The authors also conducted analyses to identify factors contributing to treatment disparities. Low-income subsidy status, of which 87.6% was dual-eligible for Medicaid and Medicare, explained 20% to 45% of the disparities across cancer types.

In the discussion section of their paper, the authors emphasized four central findings: large Black-White disparities in receiving any systemic therapy, the disappearance of survival differences once treatment was given, the substantial role of low-income subsidy status in explaining disparities and overall low use of guideline-concordant care across all groups. “Collectively, these findings can be used to inform future cancer-health equity care delivery and policy interventions,” Lin and his colleagues wrote.

“Black patients are less likely to receive any treatment at all,” the authors wrote, highlighting that once therapy began, survival differences by race were no longer statistically significant. The researchers concluded that future efforts to reduce inequities should target early steps in the treatment cascade, particularly ensuring access to first-line systemic therapy, while also addressing the unique needs of beneficiaries with low-income subsidy status or dual eligibility.

In an editorial accompanying the study, Jennifer L. Lund, Ph.D., and Vanessa E. Slater, Ph.D., of the University of North Carolina at Chapel Hill, and Allison Magnuson, M.S., D.O., of the University of Rochester, emphasized the importance of moving from documenting disparities to developing and implementing interventions that achieve equity in cancer treatment.

Lund and her co-authors suggested that future research should look beyond the initial cascade steps of diagnosis and treatment initiation. They highlighted opportunities to study cancer screening and early detection, integrate genomic testing into analyses, and examine later phases of care such as treatment modifications, supportive services, and palliative care.

They concluded that increasing receipt of guideline-concordant first-line systemic therapy for older Black adults remains an urgent priority. Addressing disparities, they wrote, will require multifaceted collaboration to design interventions that ensure all patients can access high-quality care.