Innovations Versus Health Equity? Effects of Cancer Treatment Advancements on Disparities in Mortality: A Quasi-Experimental Study

PURPOSE In the past decade, advanced lung cancer and melanoma have witnessed a surge in Food and Drug Administration (FDA)–approved treatment innovations. Yet, the impact of these advancements on population-level survival and survival disparities remains unclear. We aimed to evaluate whether cancer treatment innovations were associated with survival disparities by county-level income. METHODS This quasi-experimental study used data from the SEER registry, including 357,095 adults diagnosed with advanced cancers that experienced significant treatment advancement between 2007 and 2016 (melanoma and non–small cell lung cancer NSCLC) and cancers that lacked similar advancements (bladder, uterine, head and neck, and liver cancers). Using a difference-in-difference-in-differences approach, we compared changes in 2-year survival between cancers with and without treatment advancement and quantified survival disparities as the differences in these changes between high-income and low-income counties. RESULTS Between 2007 and 2016, cancer treatment approvals resulted in an adjusted survival increase of 3.7 percentage points (95% CI, 2.7 to 4.6) for NSCLC and 16.8 percentage points (95% CI, 14.5 to 19.2) for melanoma. The approval of epidermal growth factor receptor tyrosine kinase inhibitors and anti–PD-1 immunotherapies for NSCLC was associated with increased survival disparities between high-income and low-income counties by 2.4 percentage points (95% CI, 0.07 to 4.7). The approval of PD-1 inhibitors and BRAF/MEK inhibitors for melanoma was associated with an increase in survival disparity by 6.1 percentage points (95% CI, 0.1 to 12.1). CONCLUSION Although FDA approvals are significantly associated with improved survival in NSCLC and melanoma, they have also exacerbated survival disparities. These findings indicate a possible causal link between new therapeutic innovations and health disparities, emphasizing the need to integrate equity considerations into policies related to drug pricing, coverage, and dissemination to mitigate disparity impacts and to address systemic inequities.