Cancer Causes & Control

Hymel, Emma; Kabayundo, Josiane; Napit, Krishtee; Nichols, Amelia; Watanabe-Galloway, Shinobu

doi: 10.1007/s10552-026-02183-8pmid: 42217059

PurposeRelatively few studies have focused on thyroid cancer in the adolescent and young adult (AYA) population. The objective of this study was to examine racial/ethnic and geographic predictors of thyroid cancer stage at diagnosis and survival in the AYA population.MethodsThis population-based longitudinal study uses data from the Surveillance, Epidemiology, and End Results (SEER)-22 registries database. Primary cases of malignant thyroid cancer from 2000 to 2021 diagnosed among individuals aged 15–39 were included. Multinomial logistic regression models were used to examine the association between race/ethnicity and rurality (measured using Rural Urban Continuum codes) with stage at diagnosis (measured using SEER summary stages). Cox proportional hazards regression models were used to examine the association between race/ethnicity and rurality and both cancer-specific and all-cause mortality.ResultsOur study included 74,215 AYAs with thyroid cancer. Approximately, 8% of the cases resided in rural counties. The association between race/ethnicity and stage at diagnosis differed by rurality (p = 0.010). Among AYAs with thyroid cancer, living in a rural county at diagnosis was associated with an increased hazard of all-cause mortality (aHR = 1.41, 95% CI 1.13–1.76). Additionally, compared to non-Hispanic White AYAs, the hazard of thyroid cancer-specific mortality was highest among non-Hispanic Black (aHR = 3.66, 95% CI 2.37–5.65) and Hispanic (aHR = 1.85, 95% CI 1.32–2.60) AYAs.ConclusionWe observed racial and geographic differences in thyroid cancer stage at diagnosis and survival among AYAs in the USA. Future research should explore the underlying causes of these disparities and identify potential opportunities for intervention.

Namin, Sima; Wall, Jonathan S.; Heidel, R. Eric; Brooks, Ashton; Allen, Savannah; Ferris, Jennifer

doi: 10.1007/s10552-026-02190-9pmid: 42240725

PurposeDespite improvements in early detection, Tennessee ranks among the top ten states for breast cancer mortality among women. Mammography screening and early diagnosis are critical to reducing mortality, yet access and uptake vary widely across the State. We tested whether access to diagnostic services affected screening in the State.MethodsWe merged CDC PLACES estimates of screening among women aged 50–74 with geocoded FDA-certified mammography facilities to derive drive-time categories. Tract covariates included education, poverty, insurance, race/ethnicity, primary care provider density, urban/rural status, and Appalachian designation. We mapped hot/cold spots using Getis-Ord Gi* and fit four nested beta-regression models: geography only, socioeconomic only, combined, and combined plus log-provider density.ResultsMedian screening prevalence was 74.8%. Hotspots clustered around Memphis, Nashville, and Knoxville; cold spots in Central Appalachian and western floodplain tracts. Geography explained ~ 23% of between-tract variation (pseudo-R2 = 0.238); socioeconomic covariates ~ 61% (0.607). In combined models, drive-time and Appalachian effects attenuated. Urban tracts screened 0.72 percentage points (pp) higher than rural, and each 1-pp rise in adults without a high-school diploma predicted − 0.13 pp. ConclusionUrbanicity and education were the primary drivers of mammography screening disparities in Tennessee. To improve early diagnosis and outcomes, interventions should prioritize educational outreach, poverty reduction, insurance expansion, and improved geographic access, via mobile units or telehealth, targeting remote cold-spot tracts.

Neelam, Harish; Irfan, Furqan; Wahl, Robert; Hirko, Kelly A.

doi: 10.1007/s10552-026-02188-3pmid: N/A

PurposeWe examined the associations between county-level endocrine-disrupting pesticide usage and breast cancer incidence, overall and by metropolitan status.MethodsThis ecological study used publicly available data from the United States Geological Survey on county-level agricultural pesticide usage (in kilograms). We focused on 38 pesticides with endocrine-disrupting properties relevant in breast cancer etiology, which were categorized by chemical class as follows: carbamates, neonicotinoids, organochlorines, organophosphates, phosphonates, pyrethroids, triazines, and other miscellaneous compounds. The analysis included 2,457 U.S. counties with data on pesticide usage (2001–2015) and age-adjusted breast cancer incidence rates (2016–2020), accounting for a latency period. Metropolitan status was assessed using the 2013 Rural–Urban Continuum Codes. Gamma regression models with a log-link function were used to estimate rate ratios (RR) and 95% confidence intervals (CI) between pesticides (per interquartile range increase) and age-adjusted breast cancer incidence rates, adjusting for county-level covariates including % smoking, % poverty, % unemployed, % no high school diploma, % uninsured, and residential mobility.ResultsTotal median pesticide use was higher in rural vs. urban counties (17,523 kg vs. 14,743 kg; p < 0.05), with some variation by pesticide class. Pesticide use was associated with slightly higher breast cancer incidence in rural counties (RR = 1.02 (95% CI 1.01, 1.03)), but not in urban counties (RR = 1.00 (95% CI 1.00, 1.00)) (pint < 0.001). Associations differed by pesticide type.ConclusionResults suggest modest positive associations between county-level endocrine-disrupting pesticide use and breast cancer incidence in rural U.S. counties, with variation by pesticide type. These findings highlight the need for further research to inform targeted prevention efforts.