Background: The Affordable Care Act (ACA) led to improvements in insurance coverage and care affordability in cancer patients. However, the uninsured rate for the general US reached its nadir in 2016 and has been increasing since. We aimed to quantify the changes in insurance coverage and rate of care unaffordability in cancer survivors from 2016 to 2019. Methods: We queried data from the Behavioral Risk Factor Surveillance System (2016-2019) for cancer survivors ages 18-64 years. Outcomes of interest were the percentage of cancer survivors reporting insurance coverage and the percentage reporting cost-driven lack of care in the previous 12 months. Survey-weighted linear probability models adjusted for covariates (age, sex, race/ethnicity, income, education, marital status, and state Medicaid expansion status) were utilized to estimate the average yearly change (AYC) in the outcomes across 2016-2019. Mediation analyses evaluated the mediating effect of insurance coverage changes on changes in cost-driven lack of care. Results: A total of 178,931 cancer survivors were identified among the survey respondents. The percentage of insured cancer survivors between 2016 and 2019 decreased from 92.4% to 90.4% (AYC: -0.54, 95% CI = -1.03 to -0.06, P =.026). This translates to an estimated 164,638 cancer survivors in the United States who lost insurance coverage in the study period. There were decreases in private insurance coverage (AYC: -1.66, 95% CI = -3.1 to -0.22, P =.024) but increases in Medicaid coverage (AYC: 1.14, 95% CI = 0.03 to 2.25, P =.043). The decreases in any coverage were largest in individuals with income < 138% federal poverty level (FPL) (AYC: -1.14, 95% CI = -2.32 to 0.04, P =.059; compared to > 250% FPL, P_interaction=.03). Cost-driven lack of care in the preceding 12 months among cancer survivors increased from 17.9% in 2016 to 20% in 2019 (AYC: 0.67, 95% CI = 0.06 to 1.27, P =.03), which translates to an estimated 167,184 survivors in the US who skipped care due to costs. Changes in insurance coverage mediated 27.5% of the observed change in care unaffordability overall (p =.028) and 65.7% in individuals with income < 138% FPL relative to > 250% FPL (p =.045). Conclusions: Between 2016 and 2019, about 165,000 cancer survivors in the United States lost their insurance coverage and a similar number may have skipped needed care due to cost. Loss of insurance coverage was mostly among individuals with low socioeconomic status. Interventions to improve health insurance coverage among cancer survivors, such as the recent executive order to strengthen the ACA and further efforts promoting Medicaid expansion in additional states, may be important factors to mitigate these trends.