Shi, Kewei Sylvia

11064 Background: Local and state paid sick leave (PSL) mandates have been associated with increased use of preventive services, including cancer screening, and reduced emergency care utilization. Little research has examined PSL policies and cancer after diagnosis. This study evaluates associations of PSL policies and timely treatment initiation among women with early-stage breast cancer. Methods: We identified patients aged 18-64 years newly diagnosed with stages 0-II breast cancer from the National Cancer Database in 2004-2023 and linked then to area-level policy implementation, measured as the month and year the state, county, or city required PSL. Primary outcomes were receipt of definitive surgery or neoadjuvant therapy within 30, 60, and 90 days of diagnosis. We compared changes in treatment initiation between patients residing in areas with and without PSL policies during and after the month and year of diagnosis. We used a staggered difference-in-differences design to account for differential timing of implementation, adjusting for patient demographics, clinical, and area-level characteristics. Random errors were clustered at the state level. Supplemental analyses stratified by county-level unemployment rates and individual insurance coverage. Results: The study included 1,891,411 patients, of whom 249,313 (13.2%) resided in an area with PSL policies at diagnosis. Patients in areas with PSL policies were more likely to have Medicaid, reside in higher-income and metropolitan areas. PSL policy implementation was significantly associated with a 3.4 percentage point (PPT) increase in the probability of treatment ≤30 days (95% CI: 1.1-5.7), 3.0 PPT increase ≤60 days (95% CI: 1.6-4.3), 1.3 PPT increase ≤90 days (95% CI: 0.5-2.1) (Table). Improvements in timely treatment were concentrated in low-unemployment areas; no significant improvements were observed in high-unemployment areas. The magnitude of associations between PSL policies and treatment initiation was stronger among patients without private insurance than with private insurance. Conclusions: Local and state PSL mandates were associated with earlier treatment initiation among working-age patients with early-stage breast cancer, especially in areas with low female unemployment rate. Findings suggest that PSL policies play an important role in timely cancer treatment for employed women who may not have PSL through their jobs. Association of paid sick leave policies and breast cancer treatment initiation. Time from diagnosis to surgery/neoadjuvant therapy (days) DID PPT Lower 95% CI Upper 95% CI P-value Overall ≤30 3.4 1.1 5.7 0.004 ≤60 3.0 1.6 4.3 0.000 ≤90 1.3 0.5 2.1 0.001 Low female unemployment ≤30 2.2 -0.7 5.0 0.136 ≤60 3.8 1.8 5.8 0.000 ≤90 1.2 0.3 2.2 0.012 High female unemployment ≤30 1.8 -0.6 4.2 0.145 ≤60 -1.2 -4.5 2.0 0.459 ≤90 -1.4 -3.7 0.9 0.232

Background: Hormone receptor (HR)–negative, HER2-positive (also called HER2-enriched) breast cancer has no worse prognosis than other breast cancers if it is treated with HER2-targeted therapy. Medicaid expansion under the Affordable Care Act (ACA) has been shown to be associated with improved access to care and outcomes for many cancers, but its association with receipt of care for HR-negative, HER2-positive breast cancer is unknown. We examined the association of Medicaid expansion with receipt of guideline-concordant treatment, time to treatment initiation, and survival among nonelderly women newly diagnosed with HR-negative, HER2-positive breast cancer. Patients and Methods: Women aged 18 to 62 years newly diagnosed with HR-negative, HER2-positive breast cancer between 2010 and 2018 were identified from the National Cancer Database. Outcomes included receipt of stage-based guideline-concordant treatment, timely initiation of treatment (<30 days, <60 days, <90 days from diagnosis), and stage-specific 2-year overall survival. A difference-in-differences (DID) analytic approach compared outcome changes following Medicaid expansion in expansion versus nonexpansion states. Multivariable linear probability models were used to estimate treatment outcomes, and flexible parametric survival models were used to evaluate survival, adjusting for sociodemographic and clinical confounders. Results: A total of 31,401 patients were included. Medicaid expansion was associated with an increase of 0.58 percentage points (ppt; 95% CI, 0.01–1.16) in receipt of guideline-concordant treatment overall, a 2.43-ppt (95% CI, 0.68–4.18) increase in initiating guideline-concordant treatment <60 days after diagnosis, and a 1.17-ppt (95% CI, 0.02–2.32) increase in 2-year survival rate. The increase in 2-year survival associated with Medicaid expansion was most prominent for patients with stage III disease (DID, 3.81; 95% CI, 0.82–6.80). Conclusions: Medicaid expansion was associated with improved care and survival for patients with HR-negative, HER2-positive breast cancer, an aggressive cancer type for which prognosis largely depends on access to effective treatment.

Abstract Female breast cancer is a common cancer in young adults, an age group with the highest uninsured rate. Among 51 675 young adult women (ages 18-39 years) diagnosed with breast cancer between 2011 and 2018 in the National Cancer Database, we estimated changes in guideline-concordant treatment receipt, treatment timeliness, and survival associated with the Affordable Care Act Medicaid expansion. Of young adults with stage I-III estrogen receptor–positive or progesterone receptor–positive breast cancer, Medicaid expansion was associated with a net increase of 2.42 percentage points (95% confidence interval [CI] = 0.56 to 4.28 percentage points) in the percentage receiving endocrine therapy. Among all young adults with stage I-III breast cancer, Medicaid expansion was associated with a net reduction of 1.65 percentage points (95% CI = 0.08 to 3.22 percentage points) in treatment delays defined as treatment initiation of at least 60 days after diagnosis and a net increase of 1.00 percentage points (95% CI = 0.21 to 1.79 percentage points) in 2-year overall survival. Our study provides evidence of benefit in cancer care and outcomes from Medicaid expansion among the young adult population.

6539 Background: HER2-enriched breast cancer (estrogen and progesterone receptors negative and HER2-positive) has no worse prognosis than other breast cancers if it is treated with HER2-targeted therapy. Medicaid expansion under the Affordable Care Act (ACA) has been shown to be associated with improved access to care and outcomes for many cancers, but its impact on care for HER2-enriched breast cancer is unknown. To fill this gap, we examined the association of Medicaid expansion with receipt of guideline-concordant treatment, time to treatment, and survival among newly diagnosed nonelderly women with HER2-enriched breast cancer. Methods: Women aged 18-62 years newly diagnosed with HER2-enriched breast cancer between 2010 and 2018 were identified from the National Cancer Database. Our primary outcomes included receipt of stage-based guideline-concordant treatment, initiation of treatment <60 days, and stage-specific 2-year overall survival. A difference-in-differences (DD) approach compared outcome changes following the expansion in Medicaid expansion vs. non-expansion states. A linear probability model estimated treatment outcome, and a flexible parametric survival model evaluated survival. All models were clustered at the state level and adjusted for age group, race/ethnicity, rurality of residence, zip code-level income, comorbidity, and diagnosis year. Results: A total of 31,354 patients with HER2-enriched breast cancer were included, including 19,255 in expansion states and 12,099 in non-expansion states. Compared to patients in expansion states, patients in non-expansion states were more likely to be racial/ethnic minorities, uninsured, and diagnosed at late-stage. Medicaid expansion was not significantly associated with changes in receipt of surgery for stage I-III disease but was associated with an increase of 4.42 percentage points (ppt, 95% CI: 0.09, 8.74) in receipt of chemotherapy/targeted therapy for stage IV disease, with an increase from 90.4% pre-expansion to 92.8% post-expansion in expansion states and a decrease from 93.7% to 91.9% in non-expansion states. Medicaid expansion was also significantly associated with a 2.41 ppt increase in initiating guideline-concordant treatment within 60 days (95% CI: 0.66, 4.17; 83.5% to 82.5% in expansion states vs. 86.6% to 83.7% in non-expansion states), and a 1.18 ppt increase in two-year survival rate (95% CI: 0.03, 2.33; 94.0% to 94.9% in expansion states vs. 94.3% to 94.1% in non-expansion states). The increase in two-year survival associated with Medicaid expansion was most prominent for stage III patients (DD=3.63 ppt; 95% CI: 0.64, 6.62). Conclusions: Medicaid expansion was associated with increased receipt of timely treatment and improved 2-year survival among nonelderly women newly diagnosed with HER2-enriched breast cancer.

1509 Background: Medicaid expansion under the Affordable Care Act has been shown to increase insurance coverage and early-stage cancer diagnoses for young adults (YAs), the age group with the highest uninsured rate. We examined whether Medicaid expansion was associated with increased receipt of timely, guideline-concordant treatment and survival among YA women newly diagnosed with breast cancer, the most common YA cancer diagnosis. Methods: Using the National Cancer Database, we identified 51,675 women aged 18-39 years who were diagnosed with breast cancer in 2011-2018. We applied the difference-in-differences (DD) method to estimate outcome changes pre vs. post Medicaid expansion, in expansion- vs. non-expansion states. Linear probability models estimated associations of Medicaid expansion with receipt of guideline-concordant treatment – including any endocrine therapy among women with ER-positive or PR-positive breast cancer, and any chemotherapy or targeted therapy among women with ER-negative and PR-negative breast cancer – and initiation of guideline-concordant treatment (surgery, chemotherapy, or targeted therapy for stage I-III diagnoses, and systemic therapy for stage IV diagnoses) <60 days after diagnosis. Flexible parametric survival models were used to estimate 2-year overall survival. DD models also adjusted for age, race/ethnicity, rurality, zip code-level income, comorbidity, and diagnosis year, with standard errors clustered at the state level. Analyses were stratified by stage at diagnosis (stage I-III vs. IV). Results: Of the subset of women with stage I-III ER-positive or PR-positive breast cancer, the percentage receiving endocrine therapy increased in expansion states (85.20% pre-expansion to 86.46% post-expansion), but decreased in non-expansion states (84.32% to 82.79%), resulting in a net increase of 2.42 percentage points (ppt; 95% CI = 0.56 to 4.28) associated with Medicaid expansion in the adjusted DD model. Among all women with stage I-III breast cancer, the percentage with treatment initiation <60 days after diagnosis decreased less in expansion states (84.10% pre-expansion to 82.36% post-expansion) than in non-expansion states (86.95% to 83.98%), resulting in a net reduction of 1.61 ppt (95% CI = 0.05 to 3.18) in treatment delays associated with Medicaid expansion. Notably, the 2-year overall survival increased in expansion states (96.84% pre-expansion to 96.99% post-expansion), but decreased in non-expansion states (97.24% to 96.30%), resulting in a net survival increase of 1.00 ppt (95% CI = 0.21 to 1.79) associated with Medicaid expansion. Conclusions: Among YA women with stage I-III breast cancer, Medicaid expansion was associated with increased receipt of guideline-concordant treatment, reduced delays in treatment initiation, and improved 2-year survival.