Abstract
BACKGROUND: The COVID-19 pandemic and associated shutdowns disrupted healthcare access and resulted in decreased cancer screenings. Cancer diagnosis delays have concerning downstream effects on late-stage cancer, especially for marginalized populations. METHODS: The study population included 349,458 adults in the California Cancer Registry diagnosed with cancer between January 2019 and December 2021, during which California experienced two stay-at-home orders. We examined the percentage of late-stage (III-IV) cancer diagnoses across five periods: Pre-pandemic (January 2019-February 2020), Shutdown #1 (March-June 2020), Post-shutdown #1 (July-November 2020), Post-shutdown #2 (December 2020-March 2021), and Post-vaccine rollout (April-December 2021). To examine the association between time period and late-stage diagnoses, we conducted a multivariable log-binomial regression model adjusted for sociodemographic and neighborhood factors. RESULTS: The percentage of late-stage cancer diagnoses increased during Shutdown #1 (+5.2%) and returned to baseline Post-vaccine rollout. Groups with notably higher increases in the percentage of late-stage cancer (vs. overall population) during Shutdown #1 include Pacific Islander (+13.7%), Thai (+11.2%), Chinese (+8.1%), Native Hawaiian (+7.4%), Filipino (+6.6%), and uninsured (+7.4%). Uninsured [vs. private insurance; prevalence ratio (PR), 1.41], low neighborhood socioeconomic status (nSES; vs. high; PR, 1.19), and racial and ethnic minoritized groups (vs. non-Hispanic White; PR, 1.04-1.19) had higher likelihood for late-stage cancer diagnosis. CONCLUSIONS: The pandemic exacerbated late-stage cancer disparities for racial and ethnic minoritized groups, underinsured, and low nSES communities in California (2020-2021). IMPACT: Interventions to improve cancer screening must be focused on racial and ethnic minoritized, underinsured, and low nSES communities, as they are likely to be more vulnerable to healthcare disruptions like the pandemic.